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Phase 1 Report For
Prairie Island Indian Community
Net Zero Project
July 1, 2021
Prepared For:
Minnesota Department of Commerce
Minnesota House of Representatives Climate and Energy Finance and Policy Committee
Minnesota Senate Energy and Utilities Finance and Policy Committee
TABLE OF CONTENTS
OVERVIEW ............................................................................................................... 11
1.1
PRAIRIE ISLAND INDIAN COMMUNITY ...................................................................... 11
1.1.1
1.1.2
1.1.3
1.2
Community History ...........................................................................................................11
How the Prairie Island Indian Community Came to Be.....................................................11
The Creation of the Prairie Island Reservation .................................................................11
NET ZERO PROJECT ORIGINS ..................................................................................... 12
1.2.1
1.2.2
1.2.3
1.2.4
Brief History of Net Zero Project.......................................................................................12
Net Zero Project Overview ...............................................................................................12
Net Zero Importance ........................................................................................................12
Report Outline ..................................................................................................................13
COMMUNITY AND STAKEHOLDER ENGAGEMENT ...................................................... 14
2.1
PURPOSE ................................................................................................................. 14
2.2
METHODOLOGY AND INPUT PROCESS ...................................................................... 14
2.2.1
2.2.2
2.2.3
2.2.4
Review Existing Documents and Plans..............................................................................14
Stakeholder Engagement Process ....................................................................................15
2.2.2.1
Tribal Leadership Group Sessions ...................................................................15
2.2.2.2
Program Staff and Tribal Council Interviews...................................................15
2.2.2.3
Steering Committee Updates..........................................................................16
2.2.2.4
Tribal Council Updates ....................................................................................16
Community Meetings .......................................................................................................16
2.2.3.1
Elder Meetings ................................................................................................16
2.2.3.2
Youth Meetings ...............................................................................................17
Survey ...............................................................................................................................17
2.2.4.1
Quantitative ....................................................................................................17
2.2.4.2
Qualitative.......................................................................................................22
2.3
STRENGTHS, WEAKNESSES, OPPORTUNITIES, AND THREATS ..................................... 23
2.4
VISION, VALUES, AND GUIDING PRINCIPLES.............................................................. 25
2.4.1
2.4.2
2.4.3
Net Zero Project Vision .....................................................................................................25
Core Values .......................................................................................................................25
Guiding Principles .............................................................................................................26
ENERGY BASELINE AND SYSTEM STUDY .................................................................... 27
3.1
PROFILES OF UTILITY SERVICE AND CONSUMPTION .................................................. 27
3.1.1
3.1.2
3.2
2019 Base Year .................................................................................................................27
3.1.1.1
Buildings and Purchased Utilities ....................................................................27
3.1.1.2
Fleet Vehicles ..................................................................................................30
3.1.1.3
Water ..............................................................................................................32
Base Year Consumption and Emissions Benchmark .........................................................33
3.1.2.1
Buildings and Purchased Utilities ....................................................................34
3.1.2.2
Fleet Vehicles ..................................................................................................35
3.1.2.3
Net Zero Emissions Benchmark ......................................................................35
ENERGY ASSESSMENTS ............................................................................................ 36
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
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NET ZERO TARGET – INVESTIGATED MEASURES ........................................................ 37
4.1
ALIGNMENT WITH COMMUNITY AND STAKEHOLDER ENGAGEMENT ......................... 37
4.2
ENERGY EFFICIENCY ................................................................................................. 37
4.2.1
4.2.2
4.2.3
4.3
RENEWABLE GENERATION ....................................................................................... 41
4.3.1
4.3.2
4.3.3
4.4
4.4.1.1
Lithium Ion (Li-ion) ..........................................................................................46
Conclusion ........................................................................................................................46
INTERCONNECTION OPTIONS ................................................................................... 47
4.5.1
4.5.2
4.5.3
4.5.4
4.5.5
4.5.6
4.5.7
4.5.8
4.6
Solar ..................................................................................................................................42
On-Shore Wind .................................................................................................................42
4.3.2.1
Global Wind Atlas ...........................................................................................43
4.3.2.2
NREL Wind Prospector ....................................................................................44
Hydroelectric Power .........................................................................................................45
ENERGY STORAGE .................................................................................................... 46
4.4.2
4.5
Casino-Hotel Resort ..........................................................................................................37
4.2.1.1
Kitchen Hood Controls ....................................................................................37
4.2.1.2
Monitoring-Based Commissioning or Equivalent ...........................................38
4.2.1.3
Lighting............................................................................................................39
4.2.1.4
Lighting Controls .............................................................................................39
4.2.1.5
Exterior Lighting ..............................................................................................39
4.2.1.6
Ventilation Energy Recovery ...........................................................................39
4.2.1.7
Water Measures .............................................................................................40
Tribal Buildings..................................................................................................................40
4.2.2.1
Lighting............................................................................................................40
4.2.2.2
Water Plant .....................................................................................................40
Residential ........................................................................................................................41
4.2.3.1
Energy Report and Monitoring .......................................................................41
4.2.3.2
Water Measures .............................................................................................41
Net Metering ....................................................................................................................47
Self-Generation .................................................................................................................47
DEA 5% Renewable Program ............................................................................................48
Wholesale Generation ......................................................................................................48
Technical Considerations ..................................................................................................48
4.5.5.1
Great River Energy ..........................................................................................49
4.5.5.2
Dakota Electric Association .............................................................................49
Solar Analysis ....................................................................................................................50
4.5.6.1
Residential ......................................................................................................50
4.5.6.2
Distributed Generation ...................................................................................51
4.5.6.3
Ground-Mount ................................................................................................51
Potential Siting Map .........................................................................................................53
Transpired Solar Thermal..................................................................................................54
ELECTRIFICATION ..................................................................................................... 54
4.6.1
Casino-Hotel Resort ..........................................................................................................55
4.6.1.1
Laundry Washer/Extractor Washwater ..........................................................55
4.6.1.2
Laundry Dryers ................................................................................................55
4.6.1.3
Electric Stovetops and Ovens..........................................................................57
4.6.1.4
Air Source Heat Pumps ...................................................................................57
4.6.1.5
Heat Recovery Ground Source Heating Plant .................................................57
4.6.1.6
Temperature Modification of Heating System ...............................................60
4.6.1.7
Domestic Hot Water .......................................................................................60
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
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4.6.2
4.6.3
4.6.4
4.7
Tribal Buildings..................................................................................................................61
4.6.2.1
Heat Pump Water Heaters ..............................................................................61
4.6.2.2
Air Source Heat Pumps ...................................................................................61
4.6.2.3
Ground Source Heat Pumps ............................................................................61
Residential ........................................................................................................................62
4.6.3.1
Heat Pump Water Heater ...............................................................................62
4.6.3.2
Electric Stovetops and Ovens..........................................................................62
4.6.3.3
Electric Dryers .................................................................................................63
4.6.3.4
Air Source Heat Pump .....................................................................................63
Vehicle Fleets ....................................................................................................................63
PERFORMANCE AND EMISSIONS .............................................................................. 66
4.7.1
4.7.2
Potential Reduction of Purchased Utilities and Energy ....................................................66
Potential Reduction of CO2 Emissions ..............................................................................66
4.8
OPINION OF CAPITAL COST....................................................................................... 67
4.9
COMPLEMENTARY ACTIONS FOR CO2 EMISSIONS ..................................................... 68
4.9.1
4.9.2
4.9.3
4.9.4
4.10
LEED and Building Codes...................................................................................................68
Locally Sourcing Food .......................................................................................................69
Sequestration—Forest and Prairie Flora ..........................................................................69
Green Power Options .......................................................................................................69
4.9.4.1
Renewable Energy Certificates .......................................................................69
4.9.4.2
Purchased Power Agreements (PPA) ..............................................................70
4.9.4.3
Shared Renewable Resources .........................................................................70
FUTURE GROWTH .................................................................................................... 70
4.10.1
4.10.2
Residential ........................................................................................................................70
Commercial and Tribal ......................................................................................................70
NET ZERO IMPLEMENTATION PLAN .......................................................................... 71
5.1
PRIORITY AREAS ...................................................................................................... 71
5.1.1
5.1.2
5.1.3
5.2
Energy Efficiency ...............................................................................................................72
Renewable Energy Generation .........................................................................................72
Energy Resiliency and Sovereignty ...................................................................................72
IMPLEMENTATION PLAN .......................................................................................... 73
NET ZERO PROJECT PROCUREMENT PLAN ................................................................. 76
6.1.1
SCOPE OF SOLICITATIONS .................................................................................................76
6.2
GUIDING POLICIES ................................................................................................... 76
6.3
PROCUREMENT PLAN OBJECTIVES AND STRUCTURE ................................................. 76
6.3.1
6.4
PIIC Principles ...................................................................................................................77
6.3.1.1
General Outreach ...........................................................................................77
6.3.1.2
PIIC NZ Net Zero Project Procurement Website ............................................77
6.3.1.3
Specific Solicitation Outreach .........................................................................78
SOLICITATION PROCESS............................................................................................ 78
6.4.1
Solicitation Planning .........................................................................................................78
6.4.1.1
Bid Package Categories ...................................................................................78
6.4.1.2
Simplified Procurement Process for Minor Net Zero Projects ........................78
6.4.1.3
Net Zero Project Packages ..............................................................................78
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
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6.5
SPECIFIC SOLICITATION PLANNING ........................................................................... 79
6.5.1
6.5.2
6.5.3
6.5.4
6.5.5
RFP Development .............................................................................................................79
Bidder Conferences ..........................................................................................................79
Scoresheet Development and Evaluation ........................................................................79
Shortlist Interviews ...........................................................................................................79
Selection and Use of Proposal Data ..................................................................................80
6.6
PERMITS AND AUTHORIZATIONS .............................................................................. 80
6.7
CONTRACTING ......................................................................................................... 80
FUTURE CONSIDERATIONS........................................................................................ 81
7.1
GOVERNANCE AND OPERATIONS ............................................................................. 81
7.1.1
7.1.2
7.1.3
Governance Structures .....................................................................................................81
7.1.1.1
Tribal Business Entities ...................................................................................81
7.1.1.2
Tribal Utility ....................................................................................................82
7.1.1.3
Tribal Department...........................................................................................82
Operations and Maintenance ...........................................................................................82
Oversight...........................................................................................................................82
7.2
LONG TERM STRATEGIES .......................................................................................... 82
7.3
ECONOMIC OPPORTUNITIES..................................................................................... 84
7.3.1
Leveraged Funding ............................................................................................................85
SUMMARY CONCLUSION .......................................................................................... 86
APPENDIX ................................................................................................................ 87
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
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LIST OF FIGURES
Figure 1 – Targeted Reduction of CO2 Emissions by Measure ................................................................. 3
Figure 2 – Benchmark and Anticipated Reductions Based on Selected Net Zero Projects ................... 3
Figure 3 – Age Breakdown of Survey Respondents................................................................................ 18
Figure 4 – Energy Priorities for the Community ...................................................................................... 18
Figure 5 -- Environmental Impact Concerns ............................................................................................ 19
Figure 6 – Community Improvement Opportunities ............................................................................... 20
Figure 7 – Loss of Electricity (on Reservation)........................................................................................ 21
Figure 8 – Loss of Electricity (off Reservation) ....................................................................................... 21
Figure 9 – Open Ended Responses ......................................................................................................... 22
Figure 10 – SWOT Analysis ...................................................................................................................... 24
Figure 11 – Guiding Principles ................................................................................................................. 26
Figure 12 – Major Energy User Groups ................................................................................................... 27
Figure 13 – Base Year Utility Consumption by User Group .................................................................... 28
Figure 14 – Annual Consumption Patterns – Electricity ........................................................................ 29
Figure 15 – Annual Consumption Patterns – Natural Gas..................................................................... 29
Figure 16 – Annual Consumption Patterns – Propane .......................................................................... 30
Figure 17 – Base Year Fuel Consumption by Vehicle Fleet ................................................................... 31
Figure 18 – General Comparison of PIIC Tribal Government Vehicle Fleet Fuel Consumption ........... 31
Figure 19 – General Comparison of Treasure Island Vehicle Fleet Fuel Consumption ....................... 32
Figure 20 – Prairie Island Water Production .......................................................................................... 32
Figure 21 – TIRC Water Consumption ..................................................................................................... 33
Figure 22 – CO2 Emissions Factors ......................................................................................................... 33
Figure 23 – Base Year (2019) CO2 Emissions Benchmark by User Group and Utility ......................... 34
Figure 24 – Target Year (2023) CO2 Emissions Benchmark by User Group and Utility ....................... 34
Figure 25 – Base Year (2019) CO2 Emissions by Vehicle Fleet ............................................................. 35
Figure 26 – Total Net Zero CO2 Emissions Benchmark .......................................................................... 36
Figure 27 – NREL Solar Irradiance Map.................................................................................................. 42
Figure 28 – General Electric (GE) 2.5MW, 328’ Wind Turbine Power Profile Curve ............................ 43
Figure 29 – Average Wind Speed Map of the PIIC and Surrounding Area (Global Wind Atlas) ........... 44
Figure 30 – Average Wind Speed Map of the PIIC and Surrounding Area (NREL Wind Prospector) ... 45
Figure 31 – A123 Systems, Inc. Lithium-ion Containerized BESS ......................................................... 46
Figure 32 – Distributed Generation Solar Program Summary ............................................................... 49
Figure 33 – Residential Solar Program Summary .................................................................................. 50
Figure 34 – Distributed Generation Solar Program Summary ............................................................... 51
Figure 35 – Ground-Mount Solar Program Summary ............................................................................. 52
Figure 36 – Aerial View of the Three Potential Array Locations on the PIIC.......................................... 53
Figure 37 – Location of a Potential 2MW Array Adjacent to TIRC ......................................................... 53
Figure 38 – One of Two Potential 2MW Arrays Near the Mato Circle Residences ............................... 54
Figure 39 – The Second of Two Potential Arrays Near the Mato Circle Residences ............................ 54
Figure 40 – PIIC Tribal Government Fleet of Street Vehicles ................................................................. 64
Figure 41 – Treasure Island Fleet of Street Vehicles ............................................................................. 65
Figure 42 – Anticipated Changes in Purchased Utility Energy ............................................................... 66
Figure 43 – Potential CO2 Reduction Based on Selected Net Zero Projects ........................................ 66
Figure 44 – Benchmark and Anticipated Reductions Based on Selected Net Zero Projects .............. 67
Figure 45 – Estimated Capital Costs ....................................................................................................... 68
Figure 46 – Focus Areas........................................................................................................................... 71
Figure 47 – Cycle One Implementation ................................................................................................... 74
Figure 48 – Cycle Two Implementation ................................................................................................... 75
Figure 49 – Cycle Three Implementation ................................................................................................ 75
Figure 50 – Community Input Guiding Long-Term Strategies ................................................................ 84
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
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EXECUTIVE SUMMARY
Reshaping Our Energy Future
The Prairie Island Indian Community (PIIC or the Tribe), a federally recognized Indian Nation, is located
in southeastern Minnesota along the banks of the Mississippi River, approximately 30 miles from the
Twin Cities of Minneapolis and St. Paul. There are more than 1,050 Tribal members living on and off
the Prairie Island Indian Reservation. For decades, the Tribe has been unfairly burdened with the
negative impacts of energy production.
In addition to flooding part of the Tribe’s land during the construction of Lock & Dam #3 on the
Mississippi River, the federal government allowed for a nuclear power plant to be built adjacent to the
Reservation. Today, one of the nation’s oldest operating nuclear power plants is located approximately
700 yards from the Tribal community, along with a nuclear waste storage site containing more than
1,000 tons of highly toxic nuclear waste. Compounding the ever-present threats facing the Tribe, the
only evacuation route off Prairie Island is blocked several times daily by train traffic, with many of those
rail cars carrying highly volatile crude oil.
The Prairie Island Net Zero Project (the Net Zero Project) is empowering the Tribe to change the
historical narrative and turn energy production into a positive for its current population as well as
generations to come. The Net Zero Project is ultimately about clean air quality by eliminating the
carbon and other GHG emissions that cause illness and other chronic health issues while reducing the
negative impacts on the environment and reversing the effects of climate change. The Tribe will benefit
from this project because it will it help people prosper and live healthier lives.
Prairie Island Net Zero Project
A $46.2 million grant from the Renewable Development Account (RDA) to the PIIC will create a
comprehensive energy system for the Tribe that results in net-zero emissions. The Minnesota
Legislature approved the appropriation for the Net Zero Project during the 2020 Legislative Session.
The State established the RDA as a condition of allowing Xcel Energy to temporarily store nuclear waste
in dry casks outside its nuclear power plant.
On May 27, 2020, Minnesota Governor Tim Walz signed House File 1842. As provided in the
legislation, the “Prairie Island Net Zero Project is established with the goal of the Prairie Island Indian
Community developing an energy system that results in net zero emissions.” Further, the law states,
“The Prairie Island Indian Community must file a comprehensive Net Zero Project plan with the
commissioner of commerce and the legislative committees with jurisdiction over energy policy no later
than July 1, 2021, describing the Prairie Island Net Zero Project elements and implementation
strategy.” (Laws of Minnesota 2020, chapter 118, section 3).
This Comprehensive Net Zero Project Plan (Plan) is being filed with Minnesota Department of
Commerce Commissioner Grace Arnold, the Honorable Dave Senjem, Chair of the Minnesota Senate
Energy and Utilities Finance and Policy Committee, and the Honorable Jamie Long, Chair of Minnesota
House of Representatives Climate and Energy Finance and Policy Committee. The Plan describes how
the PIIC intends to use the funding to achieve net zero emissions for the community and details all
activities undertaken to date during Phase 1. Submission of the Plan represents the conclusion of
Phase 1 of the Prairie Island Net Zero Project. Subsequent reports will illustrate activities that the PIIC
will undertake in Phases 2 and 3.
The Opportunity
The PIIC believes this is a special moment and a unique opportunity to develop an innovative approach
to creating a net zero community, which is likely a first of its kind in Indian Country. Following a
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
1
competitive bid process, the PIIC selected a Net Zero Team comprised of Indian Energy, LLC, (Native
owned and operated), Chief Strategy Group, Inc. (Native owned and operated), and NV5, an
international engineering company, as their strategic partners for this Net Zero Project. The Net Zero
Team was tasked with assisting the PIIC in establishing clear goals for the Net Zero Project, providing
technical analysis of the PIIC’s existing energy portfolio, and developing and executing a Net Zero
Project plan that includes conservation, energy efficiency, generation, and sustainability.
Getting to Net Zero
The Prairie Island Net Zero Project is broken into three phases:
Phase 1: Stakeholder Engagement, Technical Analysis, & Net Zero Project Plan Development
Phase 2: Net Zero Project Costing and Vendor Selection
Phase 3: Construction and Implementation
Phase 1: Stakeholder Engagement, Technical Analysis, & Net Zero Project Plan
Development
The Tribe created a public input protocol by utilizing the PIIC membership as the base. Many of the
technical changes that are to take place at Prairie Island will affect Tribal members, thus it was critical
to receive feedback from the Tribal membership as to what they believe would be the best path for the
Tribe to pursue. The alignment of the community input with the technical solutions was important to
create a strategy that is technically accurate while meeting the goals and the vision of the community.
The Net Zero Team developed and executed an internal and external stakeholder engagement process
that included:
Review of existing document and plans
Stakeholder engagement process
Community meetings
A survey of community members
The Net Zero Team conducted four community meetings to engage Tribal membership as part of the
overall outreach strategy. The first two meetings were meant to capture the ideas, thoughts, and
preferences of the Tribal membership. The community meetings were instrumental in the development
of the Net Zero Project’s guiding principles, vision, and confirmation of the Tribal values. Additionally,
they provided necessary guidance on technical solutions that were preferred by the community
members. Lastly, these first two sessions directly influenced the priority areas for the Net Zero Project,
as well as an understanding of the long-term needs and desired governance options.
The third and fourth meetings focused on confirming the information and insights gained from the first
two meetings. Technical solutions were presented and shared, as was information on why some
options may be preferred over others. These meetings and interactions allowed the community to
ensure that their thoughts, ideas, and concerns had been appropriately captured and addressed. More
importantly, awareness was generated and buy-in was created through the inclusion of the
community’s ideas.
The Net Zero Team conducted a comprehensive assessment of source energy and end-use emissions
to create an emissions baseline. A multi-disciplinary team of Engineers spent three weeks on the Island
with the Faculty staff gathering and analyzing data. After analyzing all the data, the Net Zero Team
concluded that the Tribe would need to eliminate approximately 20M lbs. of CO2 in 2023. See Figure 1.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
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Figure 1 – Targeted Reduction of CO2 Emissions by Measure
Type of Measure
Energy Efficiency
Electrification
Renewable Generation
TOTAL
Reduction of CO2 Emissions
Pounds
%
3,853,717
19.8%
14,700,231
75.7%
872,117
4.5%
19,426,065
100.00%
Informed by the baseline assessment, technical analysis, and input from the stakeholder engagement,
the PIIC Tribal Council approved a comprehensive plan for the Prairie Island Net Zero Project that
maximizes carbon reduction through energy conservation, renewable energy generation, and
deployment of innovative technologies.
The PIIC Tribal Council weighed several factors, which included a wide array of technologies,
the impact on Tribal Members and Tribal business operations, cultural implications, and the
capital costs of each package and its carbon reduction potential.
The Selected Net Zero Projects are comprised of 46 individual projects, including LED lighting
and controls, a geothermal heating and cooling plant, rooftop and ground-mounted solar, and
an energy management system.
The Plan will reduce 97% of the PIIC’s carbon footprint. The remaining carbon will be reduced further
with future renewable generation or sequestered through planting native vegetation. See Figure 2.
Figure 2 – Benchmark and Anticipated Reductions Based on Selected Net Zero Projects
Phase 2: Net Zero Project Costing and Vendor Selection
Phase 2 involves Net Zero Project costing and vendor selection to create a certified cost report due to
the Minnesota Legislature by January 1, 2022.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
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Phase 3: Construction and Implementation
Phase 3 will be construction and implementation of the Plan to achieve net zero emissions.
Annual progress reports to the Legislature will begin on July 1, 2022 and continue through completion
of the Net Zero Project.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
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ACKNOWLEDGEMENTS
This work is the result of a collaboration between the Prairie Island Indian Community and several
companies, professions, and across time zones. The study would not have been completed without
the input and support of the following individuals:
Prairie Island Indian Community Tribal Council: President Shelley Buck, Vice President Lucy Taylor,
Secretary Johnny Johnson, Treasurer Valentina Mgeni, and Assistant Secretary/Treasurer Michael
Childs Jr.
Prairie Island Indian Community Net Zero Project Steering Committee: Darrell Breuer, Thomas J.
Hanson, Blake Johnson, Brad Johnson, Grant Johnson, Rayanna Lennes, Eric Pehle, John
Reich, and Jessie Seim
Prairie Island Indian Community Members: Through interviews, a survey, and small group sessions
with Tribal elders and youth, dozens of Community members provided their input to the Net Zero
Project.
Indian Energy: Henry Boulley, Allen Cadreau, Jessica Cadreau and Nicole Cadreau
Chief Strategy Group: Michell Hicks, Jason Lambert, and Bryan Small
NV5: Jack Gardner, Jennifer Guenther, Ben Juhnke, Dan Kolimar, Billy Parker, Shoshana Pena, Brian
Roppe, Tom Schubbe, Isha Shah, Collin Smith, Kyle Thompson, and Brian Wallace
Mendota Group: David Sagara and Grey Staples
Transform LLC: Carmen Barker Lemay
With the additional assistance of Dakota Electric Association, Great River Energy and Xcel Energy.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
5
ACRONYMS
AHU
Air Handling Unit
ASHP
Air Source Heat Pump
BESS
Battery Energy Storage System
BTU
British Thermal Unit
CHW
Chilled Water
COP
Coefficient of Performance
DB
Dry Bulb
DEA
Dakota Electric Association
DCW
Domestic Cold Water (potable)
DHW
Domestic Hot Water (potable)
DX
Direct Expansion
ECM
Energy Conservation Measure
EE
Energy Efficiency
ERU
Energy Recovery Unit
GHG
Greenhouse Gases
GRE
Great River Energy
GSHP
Ground Source Heat Pump (also Geothermal Heat Pump)
H.F.
House File
HHW
Heating Hot Water
HRC
Heat Recovery Chiller
HRG
Heat Recovery/Geothermal
HVAC
Heating, Ventilation, Air Conditioning
HX
Heat Exchanger
kV
Kilovolts
kWh or KWh
Kilowatt-hours
kW
Kilowatt
LCC
Lifecycle Costs
M
Million
MAU
Makeup Air Unit
MBCx
Monitoring-based Commissioning
MISO
Midcontinent Independent System Operator
MN
Minnesota
M&V
Measurement and Verification
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
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MV&A
Measurement, Verification and Analytics
MW
Megawatt
MWh
Megawatt-hour
NRG
NRG Energy
O&M
Operations and Maintenance
OH
Overhead
PEC
People’s Energy Cooperative
PF
Power Factor
PIIC
Prairie Island Indian Community
PPA
Power Purchase Agreement
PTAC
Packaged Terminal Air Conditioner
PV
Solar Photovoltaic
RDA
(Xcel Energy) Renewable Development Account
RE
Renewable Energy
RFP
Request for Proposals
RTU
Rooftop Unit
SF
Square Foot or Square Feet
SWOT
Strengths, Weaknesses, Opportunities and Threats
TIRC
Treasure Island Resort and Casino
V
Volt
VFD
Variable Frequency Drive
W
Watts
WB
Wet Bulb
WWHP
Water to Water Heat Pump
WWTF
Wastewater Treatment Facility
Xcel
Xcel Energy
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
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DEFINITIONS
Behind (or Back of) the Meter: Refers to energy that is generated and consumed and or stored by the
consumer and is typically NOT metered by the local utility.
Battery Energy Storage System (BESS): is a device that charges (stores) electrical energy from the grid,
later discharging energy to provide electricity or other grid services.
British Thermal Unit (BTU): BTU is a measure of the heat content of fuels or energy sources. It is the
quantity of heat required to raise the temperature of one pound of liquid water by 1°F at the
temperature that water has its greatest density (approximately 39°F). The measurement is used to
compare energy sources or fuels on an equal basis. Fuels (such as natural gas or electricity) can be
converted from physical units of measure (such as weight or volume) to a common unit of
measurement of the energy or heat content of each fuel.
Dry Bulb (DB): The temperature of air measured by a thermometer freely exposed to the air but
shielded from radiation and moisture.
Energy Efficiency: Measures or programs, including energy efficiency measures or programs, including
energy conservation measures or programs, that target consumer behavior, equipment, processes, or
devices designed to produce either an absolute decrease in consumption of electric energy or natural
gas or a decrease in consumption of electric energy or natural gas on a per unit or production basis
without a reduction in the quality or level of service provided to the energy consumer. (Minn. Stat.
§ 216B.241, subd. 1 (f)) https://www.revisor.mn.gov/statutes/cite/216B.241. For the PIIC
specifically, operate all facilities at the lowest cost with a focus on saving energy by educating Tribal
employees and membership on cost saving techniques. Focus on saving a dollar will result in making
a dollar.
Energy Resiliency: The ability to maintain all critical operations during high and low peak times, utilizing
the experience of the Tribe and its ability to survive while protecting the land and resources.
Energy Sovereignty: Self-generate all energy on the Reservation to benefit Tribal operations and Tribal
membership. Prairie Island becomes an island to itself with an infrastructure that is evolving and
sustainable for the benefit of the community.
Front of the Meter: Refers to energy that is generated and injected into the regional and or local
distribution grid. Examples may include roof top solar, but typically consists of community scale solar
and utility scale electric generation. These front of the meter power plants are typically financed
through a long-term power purchase agreement (PPA) with the local utility.
Global Warming: Scientific consensus holds that the rapid rise in human-caused (anthropogenic) GHG
emissions is contributing to a general warming of the earth’s atmosphere. In 2018, the International
Panel on Climate Change (IPCC) issued a special report which concluded that human activities are
estimated to have caused an approximately 1.0°C increase in global temperatures above preindustrial levels. The Report further concluded that recent trends in emissions will increase the
warming trend and that, “without increased and urgent mitigation ambition in the coming years,
leading to a sharp decline in greenhouse gas emissions by 2030, global warming will surpass 1.5°C
in the following decades, leading to irreversible loss of the most fragile ecosystems, and crisis after
crisis for the most vulnerable people and societies.”
Greenhouse Gas Emissions (GHG): The main greenhouse gases are carbon dioxide (frequently
referred to as simply “carbon” or CO2), methane, nitrous oxide, and fluorocarbons. Carbon dioxide is
the primary contributor and methane is the second largest contributor. Methane is ten times more
potent than carbon dioxide in contributing to warming.
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Ground Source Heat Pump (GSHP): Also referred to as a geothermal heat pump, a GSHP is a type of
heat pump used to heat and cool a building by exchanging heat with the ground, often through a vaporcompression refrigeration cycle. It uses the earth, without any intermittency, as a heat source or a heat
sink.
Heat Pump: A device that can provide heating, cooling and hot water for residential, commercial and
industrial applications. Any heat pump installation can provide heating and cooling in parallel.
Master Planning: Creating a plan that is expandable and flexible yet aligns with the PIIC expertise and
overall vision.
Monitoring-Based Commissioning: MBCx is an ongoing commissioning process which monitors and
analyzes large amounts of building performance data, such as that from a commercial heating and air
units, on a continuous basis.
Net Zero Project (or Project): Per H.F. 1842, net zero is defined as net zero emissions. “The Prairie
Island Net Zero Project is established with the goal of the Prairie Island Indian Community developing
an energy system that results in net zero emissions.”
Net Zero Emissions: Refers to buildings or communities where, on a source basis, the Greenhouse
Gas emissions produced by the consumed energy (and potentially other products and services) are
less than or equal to zero. Given that carbon dioxide is the primary greenhouse gas and activities that
reduce carbon also reduce other greenhouse gas emissions (such as methane), the primary focus of
the Prairie Island Net Zero Project will be to achieve net zero carbon dioxide emissions.
Net Zero Energy: Net Zero also frequently refers to net zero energy. A net zero energy building is a
building where, on a source basis, the actual annual delivered energy is less than or equal to the onsite renewable exported energy. The designated entity can be a building, a campus, a portfolio of
buildings, or a community. Other frequently used terms include: zero net energy, zero energy, or zero
net source energy use.
Net Zero Team: Indian Energy LLC, Chief Strategy Group, Inc., NV5.
PIIC NZ Procurement Plan: The plan to obtain bids to develop the Certified Cost Report. The
Procurement Plan is elaborated in Section 6 of this report.
Plan: Comprehensive Net Zero Project Plan for the Prairie Island Net Zero Project.
Prairie Island Indian Community Council: The Tribal Council is the common reference to “The
Community Council of the Prairie Island Indian Reservation.” Per the Constitution and Bylaws of the
Prairie Island Indian Community in Minnesota, as amended, it is the governing body of the Prairie
Island Indian Community. It is comprised of five, duly elected, members. Its powers, authority, and
responsibilities are identified in the amended Constitution and Bylaws.
Net Zero Project Steering Committee: The committee that was assigned the responsibility during all
phases of the Net Zero Project to assist in advising, guiding, scheduling, and providing general
oversight for the Net Zero Project.
Procurement Team: The Net Zero Project Procurement Team is a subset of the Net Zero Project Team
given the responsibilities of framing and implementing the procurement tasks associated with Phase
2 of the Net Zero Project. They work within the guidance and approval of the Net Zero Project Steering
Committee and the Tribal Council.
Therm(s): A non-SI (international system of units) unit of heat energy equal to 100,000 British thermal
units (BTU). It is approximately the energy equivalent of burning 100 cubic feet (2.83 cubic meters) –
often referred to as 1 CCF – of natural gas. According to the EPA burning one therm of natural gas
produces on average 5.3 kg (11.7 lb.) of carbon dioxide.
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Wet Bulb (WB): The temperature read by a thermometer covered in a water-soaked cloth over which
air is passed.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
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OVERVIEW
1.1
1.1.1
PRAIRIE ISLAND INDIAN COMMUNITY
Community History
The following represents a brief historical description of the Prairie Island Indian Community and its
connection to its homeland.
The Dakota Oyate (people) lived on the lands around present-day Minnesota and Prairie Island long
before European settlers first came to America or moved west. They are the Bdewakantunwan, or
“those who were born of the waters.”
Prairie Island represents more than land – it is a spiritual place that connects the Dakota to Mother
Earth. This sacred land is home to long-gathered foods and medicines that sustained the Dakota
through prosperous times and times of need. It represents a place of worship and a final resting place
for many Dakota ancestors.
The Dakota and Prairie Island are one.
Despite the taking of their land and efforts to eradicate them from what is now Minnesota, the Dakota
people persevered. Some never left and others returned, proving that the Dakota and Prairie Island
are inseparable.
1.1.2
How the Prairie Island Indian Community Came to Be
Prairie Island Indian Community Members are descendants of the Mdewakanton (Bdewakantunwan)
Band of Eastern Dakota. The Treaty of Traverse des Sioux of 1851, stripped the Dakota of their
ancestral lands. The failure of the U.S. government to uphold its treaty obligations led to war with the
Dakota people and, ultimately, the largest mass execution in American history – the hanging of 38
Dakota men in Mankato, Minnesota on December 26, 1862. Soon after, Congress invalidated treaties
and the Dakota were driven from Minnesota. A small group of Dakota remained and settled near
Prairie Island.
1.1.3
The Creation of the Prairie Island Reservation
In the late 1880’s, the Secretary of the Interior placed land into trust for Dakota individuals living on
Prairie Island. Additional land was purchased under the Indian Reorganization Act of 1934. The Act
encouraged tribes to formalize their governments by adopting a Constitution and By-Laws, which the
Prairie Island Indian Community did in 1936.
A few years later, the U.S. Government allowed the first in a series of events that created ever-present
threats to the Prairie Island Indian Community. In 1938, the U.S. Army Corps of Engineers built Lock
and Dam Number 3, which flooded much of the Community’s original land base, including burial
mounds, and created a larger floodplain. In 1973, Xcel Energy (formerly known as Northern States
Power Company) began operating a nuclear power plant and later a nuclear waste storage site
adjacent to the Reservation.
Resiliency has defined the Prairie Island Indian Community from its earliest history. Despite the many
hardships, the Tribe has persevered and survived, overcoming hurdles while focusing on preserving
Tribal culture and providing for future generations.
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1.2
1.2.1
NET ZERO PROJECT ORIGINS
Brief History of Net Zero Project
The Minnesota Legislature established the Renewable Development Account (RDA) in 1994 as a
condition to allow Xcel Energy to store nuclear waste on site in dry storage casks at the utility’s Prairie
Island nuclear power plant. Currently, Xcel Energy pays $500,000 annually into the RDA for each
nuclear waste cask stored on Prairie Island; the utility also pays $350,000 for each cask stored at its
Monticello plant.
House File 1842 (HF 1842) appropriated $46.2 million for the RDA for PIIC to become a net zero
energy community, one of the first tribes in the United States to achieve that status and one of only a
handful of Minnesota communities aiming to become net zero by reducing energy consumption,
installing energy efficient equipment and lighting, and integrating renewable generation to eliminate
the production of harmful GHG emissions. Governor Tim Walz signed the bill into law on May 27, 2020.
Prior to the Net Zero appropriation, PIIC had not received funds or benefited from the RDA, despite
shouldering the risk associated with the storage of the spent nuclear fuel in close proximity to Tribal
Member homes.
1.2.2
Net Zero Project Overview
HF 1842 authorized the PIIC to receive $46.2 million to fund a Net Zero Project. As provided in the
legislation, the “Prairie Island Net Zero Project is established with the goal of the Prairie Island Indian
Community developing an energy system that results in net zero emissions.” Further, the law states,
“The Prairie Island Indian Community must file a comprehensive project plan with the commissioner
of commerce and the legislative committees with jurisdiction over energy policy no later than July 1,
2021, describing the Prairie Island Net Zero Project elements and implementation strategy.” (Laws of
Minnesota 2020, chapter 118, section 3). This report fulfills the reporting requirement.
This Plan is being filed with Minnesota Department of Commerce Commissioner Grace Arnold,
Representative Jamie Long, Chair of the Minnesota House of Representatives Climate and Energy
Finance and Policy Committee, and Senator Dave Senjem, Chair of the Minnesota Senate Energy and
Utilities Finance and Policy Committee. The Plan describes how the PIIC plans to use the funding to
achieve net zero emissions for the community.
1.2.3
Net Zero Importance
International scientific consensus holds that the rapid rise in human-caused (anthropogenic)
Greenhouse Gas (“GHG”) emissions is contributing to a general warming of the earth’s atmosphere.
In 2018, the International Panel on Climate Change (IPCC) issued a special report1 which concluded
that human activities are estimated to have caused an approximately 1.0°C increase in global
temperatures above pre-industrial levels. The Report further concluded that recent trends in emissions
will increase the warming trend and that, “without increased and urgent mitigation ambition in the
coming years, leading to a sharp decline in greenhouse gas emissions by 2030, global warming will
surpass 1.5°C in the following decades, leading to irreversible loss of the most fragile ecosystems,
and crisis after crisis for the most vulnerable people and societies.”
Net zero is achieved by minimizing human caused emissions through energy efficiency, deploying
renewable fuels, behavior change, and offsetting what emissions remain using proven approaches to
1 Global warming of 1.5°C: An IPCC Special Report on the impacts of global warming of 1.5°C
above pre-industrial levels and related global greenhouse gas emission pathways, in the context of
strengthening the global response to the threat of climate change, sustainable development, and efforts to
eradicate poverty.
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12
remove GHGs from the atmosphere. In the context of this Plan, net zero emissions is defined as GHG
emissions, most notably carbon dioxide. The emissions are primarily produced by fossil-fuel generated
electricity, petroleum-fueled transportation vehicles, on-site consumed natural gas or propane, and
emissions from other residential and commercial activities. Given that carbon dioxide is the primary
GHG and activities that reduce carbon also reduce other GHG emissions (such as methane), the
primary focus of the Net Zero Project will be to achieve net zero carbon dioxide emissions.
A plan to achieve net zero cannot neglect the human part of the solution as technological fixes are
inextricably linked with human comfort and behavioral changes, and because the well-being of the
community is critical to achieving successful outcomes. To this end, the Net Zero Project has actively
engaged members of the PIIC and other relevant parties to better understand their needs, capture
their ideas, and create plans that meet the Net Zero Project’s objectives. Reaching the goal of net zero
emissions will be a hollow achievement without also producing significant long-term, sustainable
benefits for the community.
1.2.4
Report Outline
The plan to achieve net zero is broken into three phases:
Phase 1: Stakeholder Engagement, Technical Analysis, & Net Zero Project Plan Development (report
due July 1, 2021);
Phase 2: Net Zero Project Costing and Vendor Selection (report due January 1, 2022);
Phase 3: Construction and Implementation (progress reports beginning on July 1, 2022).
This report marks the completion of Phase 1 and activities to support Phases 2 and 3 have already
begun. Considerable effort will be expended between July 1, 2021, and January 1, 2022, to put the
Net Zero Project on a path to meet the January 1, 2022 deadline to submit the total certified cost of
the project to the state of Minnesota. The Phase 1 report is organized as follows:
Section 1 – Net Zero Project Overview: Provides a high-level Net Zero Project summary of the report
and describes the stakeholder and community engagement that supports the analysis of net zero
options and frames the Net Zero Project’s long-term benefits.
Section 2 – Community and Stakeholder Engagement: Details the process of stakeholder and
community engagement and the results that informed the selection of the Net Zero Projects.
Section 3 – Energy Baseline and System Study: Provides details regarding the Energy Baseline and
System study used to establish the net zero goal.
Section 4 – Net Zero Target: Describes the Net Zero Projects selected to achieve the net zero goal.
Section 5 – Net Zero Implementation Plan: Provides the plan for implementing the selected Net Zero
Projects.
Section 6 – Procurement Plan: Describes the plan, process and procedures the PIIC will use to procure
the necessary resources to meet the requirements of HF 1842 and ensure that the funds are prudently
spent to maximize benefits to the PIIC and the State.
Section 7 – Future Considerations: Discusses future considerations to implement the overall plan and
other longer-term considerations. Section 7 also describes next steps after this report is submitted.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
13
COMMUNITY AND STAKEHOLDER ENGAGEMENT
2.1
PURPOSE
In addition to technical feasibility, projects in Indian Country are subject to the priorities and needs of
Tribal communities and other stakeholders. Without significant buy-in from Tribal communities and
other Tribal stakeholders, the potential for long-term success of any project is likely minimal. The
purpose of the initial community and stakeholder engagement in this Net Zero Project was to
understand the priorities of the PIIC membership, staff members, and Tribal Council and generate buyin for the Net Zero Project from all these groups. Once these priorities were understood, it was possible
to design a strategy that aligned with Tribal priorities. However, true strategic alignment does not
simply include buy-in from the community and staff. It includes alignment from financial and human
resources perspectives as well. The financial and human resources piece is especially important in
this project since the Net Zero Project is so capital-intensive and requires technical expertise for
continued operations.
2.2
METHODOLOGY AND INPUT PROCESS
The methodology and input process for community engagement was designed to gather information
about the PIIC and determine the priorities, expectations, and needs of the community and
stakeholders. These processes included a review of existing documents and plans, stakeholder
engagement, community meetings, and a community survey.
A review of existing documents and plans was designed to gather data around the current state and
operational potential of the Tribal government.
The stakeholder engagement process included group and individual interviews with Tribal
Council as well as selected staff members and was designed to collect information about the
Tribal government and its current capabilities to support the Net Zero Project.
The community meetings were designed to educate, collect feedback, confirm feedback, and
present the final Net Zero report to Tribal Members, including elders and the youth.
The survey was distributed to collect both quantitative and qualitative data regarding Tribal
Member priorities and needs regarding the Net Zero Project.
These methodologies and input processes yielded significant data and information regarding
community priorities and needs. Further, the processes informed the Strengths, Weaknesses,
Opportunities, and Threats (SWOT) analysis and current capabilities of the Tribal government staff with
regards to implementation of the Net Zero Project.
2.2.1
Review Existing Documents and Plans
The document review included relevant planning documents that pertain to the PIIC, along with
organizational charts, budgets, and other appropriate documents. Organizational documents were
reviewed to gain historical context and assess the current operations and current planning efforts as
well as organizational intent. The review informed the development of the survey and tools, individual
and group interview protocol, and community sessions design. Specific documents reviewed included:
prior planning documents, organizational charts, prior annual community update reports, and
leadership communication efforts.
Tribal leadership and staff have historically engaged in project planning and budgeting activities. As
part of this engagement, the goal of the Net Zero Team was to capture essential elements of prior
planning initiatives that potentially impact the Net Zero Project and to create the protocol and design
the strategic next steps of the Tribe. From the document review phase, our Net Zero Team was able to
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
14
capture prior initiatives, goals, objectives, performance measures, and performance reports. This
information was critical to inform the next phases of the Net Zero Project and to create a picture of
how the Tribe has grown and evolved over time.
2.2.2
Stakeholder Engagement Process
The Net Zero Team collected multiple data points through the stakeholder engagement process. A
data point is defined as a key word, phrase, thought, statement or complete sentence around a subject
matter that is relevant and provides guidance to this Net Zero Project. These data points were an
accumulation of multiple input avenues that have been summarized and divided into the most
applicable area, such as SWOT, values, vision, priority areas and strategic pathways.
The purpose of the various sessions was twofold. First, the sessions were designed to understand the
current state of the PIIC and the strategy for moving forward with key initiatives. The second purpose
was to understand the key strategic initiatives the PIIC is interested in pursuing in the future related
to the Net Zero Project.
The interviews with key stakeholders in group and individual settings provide data from a slightly
different perspective than the document review. Although stakeholders are normally upfront with their
opinions regarding department interaction, these points of view can vary significantly from one another
as well as from the documents reviewed. The interviews taken in their totality provide effective
feedback around how well operations are performing as compared to the intent as laid out in formal
documents.
One facilitation technique used during this process was Ritual Dissent. Ritual Dissent is a rapid
prototyping technique designed to posit solutions to problems through quick discussions within a
“home” team and listening sessions with various other teams. The technique implements a thought
process that requires the participants to find solutions by revisiting ideas multiple times during the
sessions. This process is known to truly challenge the brain and each other's ability to criticize each
teams' thoughts and solutions until ideas and solutions are fine-tuned to the satisfaction of each
group.
2.2.2.1
Tribal Leadership Group Sessions
The Net Zero Team facilitated multiple Tribal leadership group sessions throughout this Net Zero
Project. These sessions were comprised of the PIIC Tribal Council, and staff were invited to participate
in certain sessions. The discussion around the elements of vision, values, guiding principles, and the
overall Net Zero Project strategy were critical to the future success of the Net Zero Project.
2.2.2.2
Program Staff and Tribal Council Interviews
The Net Zero Team also interviewed all of the current Tribal Council to gain insight on the Tribe’s vision,
values, guiding principles, and strategic paths of the Net Zero Project. The interviews centered on the
current state of the PIIC and identifying opportunities to grow and expand the impact of the Net Zero
Project nationally. The Net Zero Team individually also interviewed multiple program staff and
members of the Steering Committee. The interviews with the individual program staff focused on the
current state of the programs and the benefit of the Net Zero Project on their operations. Additionally,
the Net Zero Team interviewed outside stakeholders that had a current or historical perspective on
the Net Zero Project and whose input could help to guide the strategic path of the Net Zero Project.
This interview process also allowed the Net Zero Team to capture the responsibilities and expectations
of the Tribal Council for the future of the organization, both individually and collectively. The diversity
of responses, along with commonalities centered on a shared vision, informed the evaluation and
recommendation processes.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
15
2.2.2.3
Steering Committee Updates
The Net Zero Team consistently met with the Net Zero Project Steering Committee on a weekly basis
at minimum, that focused on Net Zero Project updates and continued guidance on multiple topics,
including Net Zero Project scope, scheduling, element progress, and overall direction during the first
phase of the Net Zero Project.
2.2.2.4
Tribal Council Updates
The Net Zero Team also met with the Tribal Council on a weekly basis. The purpose of the weekly
meetings was focused on Net Zero Project updates and scheduling needs. This process allowed the
Tribal Council to stay abreast of the major movements within the Project and provided our Net Zero
Team the opportunity to gain further guidance.
2.2.3
Community Meetings
A key aspect of the stakeholder engagement piece focused on community meetings with the
membership of the PIIC. Due to the extended impacts of the COVID-19 pandemic these meetings were
primarily held through virtual platforms. A total of four community-wide meetings were held between
March and June 2021. Additionally, the Net Zero Team conducted dedicated sessions for both the
Tribal elders and the Tribal youth. All of these meetings were facilitated by the Net Zero Team with the
assistance of the Steering Committee and the Tribal Council.
The first two meetings were a critical input component of capturing the ideas, thoughts, and
preferences of the Tribal membership. These were instrumental in the development of the Net Zero
Project’s guiding principles, vision, and confirmation of the Tribe’s values. Additionally, they provided
necessary guidance on technical solutions that were preferred by the community members. Lastly,
these first two sessions directly influenced the priority areas for the Net Zero Project, as well as an
understanding of the long-term needs and desired governance options. Through these meetings the
community’s knowledge of the Net Zero Project and ideas were gathered and enhanced, thereby
positively impacting the future of the PIIC.
The second two meetings focused more on confirmation of the information and insights gained from
the first two meetings. Again, facilitated by the Net Zero Team, these meetings presented the guidance
received from the community on their preferences. Technical solutions were presented and shared,
as was information on why some options may be preferred over others. These meetings and
interactions allowed the community to ensure that their thoughts, ideas, and concerns had been
appropriately captured and addressed. More importantly, awareness was generated and buy-in was
created through the inclusion of the community’s ideas.
The community meetings directly contributed to SWOT Analysis. Additionally, they provided specific
guidance for the technical paths to achieve net zero emissions.
2.2.3.1
Elder Meetings
Within Tribal communities the elder population is looked to for guidance, wisdom, and connection to
the traditional teachings and culture. Tribes often have very specific criteria for designation as an
elder. It was of the highest importance to the PIIC’s leadership that elder input was critical to the
understanding, design, and success of the Net Zero Project.
Through an existing meeting structure with the Tribal elders, the Net Zero Team was able to have two
focused meetings with the elders. Additionally, the Net Zero Team was able to interact with the elders
at several other regular meetings. All of these were held virtually. Several of the Tribal elders also
participated in the community-wide sessions, as well as the survey.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
16
Specific input from the elders focused on a trust in the responsibility they had placed in their elected
officials to make long-term, strategic decisions. The Tribal elders highly valued the positive impact this
Net Zero Project could have on younger generations, as well as those generations to come. For many
of those that had grown up and live on the Reservation, the reality of living in the shadow of a nuclear
power facility was prevalent in their concerns and their hopes. Many personal stories were shared
about how the facility and transmission lines and railway service had negatively impacted their lives.
Other comments from the Tribal elders focused on environmental impacts and opportunities for
younger Tribal members.
2.2.3.2
Youth Meetings
The Net Zero Team facilitated one face-to-face input session and one virtual input session with Tribal
youth that focused on their knowledge of the Net Zero Project and ideas on the future impact to the
PIIC. Gaining input from high school students was important for the Net Zero Project, since they will be
adults during the build out of the Net Zero Project, and they will be affected by current decisions that
impact their generation.
Nearly all of the students indicated that they didn’t know what the Net Zero Project was, however, once
the concept of Net Zero was explained, they took a keen interest and drew direct lines between net
zero and cultural values, such as protecting Mother Earth. Many of the students stated that their
favorite subjects in school were either math or science. From a workforce development
perspective, there was sincere interest in jobs that would allow the students to work with their hands
– potentially servicing the solar panels or other renewable energy generation systems.
Although the students had not been exposed to the Net Zero Project directly, their feedback and
perspectives were strongly aligned with the feedback received from other stakeholder groups.
2.2.4
Survey
A 30-question survey was developed by the Net Zero Team, reviewed by the Steering Committee and
the Tribal Council and communicated to the Tribal community. The purpose of the survey was to gain
insight from the community regarding the Net Zero Project. There was a mix of both quantitative and
qualitative questions included in the survey. The quantitative questions were designed to measure
responses across a common scale. The qualitative questions were designed to allow community
members to provide broader feedback that may not have been captured in the quantitative
questions. Communication to the community occurred through several communication avenues
including a mailing, members-only website, and the members-only Facebook page. A deadline was
established for the community members to complete the survey. The survey process began on
March 5 and closed on April 6, 2021. The deadline was extended to ensure all Members had a chance
to take the survey. A total of 74 responses were received of 570 plus community members over the
age of 18.
2.2.4.1
Quantitative
The results of the survey were used as a data point in conjunction with community meetings,
stakeholder interviews, and document review to identify and confirm overall trends within the
community at large. The sample size was not large enough to determine that any findings were
statistically significant; however, when compared to other data points collected throughout this
process, the survey results are directionally accurate.
The age groups with the highest response rates were 25-40 years old and 41-54 years old with over
36% and 32%, respectively. Just over 51% of respondents were female, about 44.5% were male, and
4% preferred not to disclose their gender. Although a significant portion of Prairie Island’s population
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
17
is under the age of 18, there were no respondents that indicated they belonged in that age
group. Figure 3 represents the age breakdown of respondents to the community survey.
More than two-thirds of respondents were
aware of the Net Zero Project. The top
three priorities around energy were solar
power (94.52%), wind power (58.9%), and
power generated from water (57.53%).
These priorities are shared in Figure 4.
Nearly 71% and over 22% of respondents
strongly agreed or agreed, respectively,
with the statement, “It is important to me
as a member of our Tribe for us to protect
the environment with the implementation
of any energy solution.” Regarding
community improvement, over 55% of
respondents ranked casino and hotel
operations as most important. Housing
and existing land development were the
second and third most important priorities,
respectively.
Figure 3 – Age Breakdown of Survey Respondents
Figure 4 – Energy Priorities for the Community
Nearly 3% of respondents lost power once a month or more. Over 56% of respondents indicated they
lost power a few times a year or once a year. Almost 41% lost power less than once a year. When
power is lost, almost 36% of respondents said it lasted less than five minutes, while over 61% indicated
power was lost for an hour or two. With respect to home energy, “supplemental solar energy” was the
highest ranked priority with a weighted score of 3.81. “Lowering monthly energy bill” and “keeping the
lights on” were the next two highest priorities with weighted scores of 3.68 and 2.97.
Regarding environmental impact, almost 43% of respondents ranked water quality as the number one
priority. Air quality was the second priority with over 38% ranking it first. These concerns around
environmental impacts are shared in Figure 5. Over 86% of respondents strongly agree or agree with
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
18
the statement, “It is important to me as a member of our Tribe that we create a PIIC Utility
enterprise that reinforces energy sovereignty.”
The top three priorities regarding economic development were sustainability of current Tribally owned
enterprises (55.41%), sustainability of current Tribal programs and services (54.05%), and
development of new Tribally owned enterprises (52.7%). Respondents indicated that clean energy
(72.6%) and access to broadband (18.06%) were higher infrastructure priorities than natural gas
(10%).
Figure 5 -- Environmental Impact Concerns
Where Tribal Members live affects both their views and priorities. For on Reservation respondents,
37.5% were 55+ and 34.38% were 41-54 years old, while 50% of off Reservation respondents were
25-40 years old and 30.95% were 41-54 years old.
Awareness of the Net Zero Project was nearly identical for respondents regardless of where they lived.
The priorities around energy were very similar as well, and they revolved around solar power, wind
power, and power generated from water. Regarding community improvement, 60% of respondents
living on the Reservation ranked the Casino and Hotel operations as most important. Housing and
existing land development were the second and third most important priorities for those living on the
Reservation, respectively. For those living off the Reservation, Casino and Hotel operations, housing,
and Tinta Wita Tipi were the top three priorities as reflected in Figure 6.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
19
Figure 6 – Community Improvement Opportunities
Regarding home energy, “supplemental solar energy” was the highest ranked priority with a weighted
score of 3.94 for those living on the Reservation. “Lowering monthly energy bill” and “keeping the
lights on” were the next two highest priorities with weighted scores of 3.63 and 2.83. For those living
off the Reservation, “lowering monthly energy bill” and “supplemental solar energy” were almost
identical as far as highest ranked priority with weighted scores of 3.72 and 3.71, respectively.
“Keeping the lights on” was the third priority with a weighted score of 3.08.
For respondents living on the Reservation, nearly 47% lost power a few times a year and over 3% lost
power once a month or more. When power was lost, over 64% of those living on the Reservation said
it lasted an hour or two and over 29% stated that it lasted less than 5 minutes. The on Reservation
electricity resiliency is displayed in Figure 7. For those living off the Reservation, less than 13% lost
power a few times a year. Less than 3% lost power once a month or more. When power was lost, almost
59% of respondents said it lasted for an hour or two, while over 41% indicated power was lost for less
than five minutes. These results are captured in Figure 8. Although the results are not statistically
significant due to the small sample size, it is important to acknowledge the differences in energy
resiliency between those living on Reservation and those living off.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
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Figure 7 – Loss of Electricity (on Reservation)
Figure 8 – Loss of Electricity (off Reservation)
With respect to environmental impact, 60% of respondents living on the Reservation ranked water
quality as the number one priority. Air quality was the second priority with 30% ranking it first. For those
living off the Reservation, water quality and air quality received the same weighted score of 4.08;
however, nearly 45% ranked air quality first, while nearly 29% ranked water quality first.
The top three priorities regarding economic development for those living on the Reservation were
sustainability of current Tribally owned enterprises (62.5%), sustainability of current Tribal programs
and services (59.38%), and development of new Tribally owned enterprises (43.75%). The top three
priorities regarding economic development for those living off the Reservation were development of
new Tribally owned enterprises (59.52%), sustainability of current Tribally owned enterprises (50%),
and sustainability of current Tribal programs and services (50%).
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
21
2.2.4.2
Qualitative
Of the 30 questions in the survey, eight provided the opportunity for an expanded narrative response.
These questions were important to provide Tribal members an opportunity to answer in their own
words, and not choose from a list of pre-selected options. These questions were strategically arranged
and placed throughout the survey rather than only at the end. Collectively, the answers and responses
from the Tribal membership provide a qualitative element of community input that will substantially
influence the Net Zero Project vision, guiding principles, SWOT Analysis, and strategic paths, while also
confirming the importance and presence of the core Tribal values.
The following questions provided the opportunity for an open-ended response:
1.
2.
3.
4.
5.
6.
7.
8.
What does Net Zero mean to you?
What would you like to see 10 years after this Net Zero Project is successfully completed?
Where is the highest impact to the PIIC resulting from the Net Zero Project?
If there is another community improvement you would like to see through this Net Zero Project,
please specify below.
What are the cultural values of the PIIC?
What are the most important cultural values that should be considered by this Net Zero
Project?
Are there other energy improvements that would be beneficial to homes in the long-term not
listed above?
What impact can and should this Net Zero Project have on youth and elders’ services?
All the open-ended questions received an adequate number of responses to influence the direction of
the Net Zero Project. Figure 9 summarizes the number of responses per open-ended question. To
highlight aspects of the qualitative data gathered from the survey instrument, an analysis of several
questions follows. Community members were asked what net zero meant to them. This question was
important to gauge understanding and provide a baseline awareness and understanding that can be
revisited in future surveys. Approximately 82% of community members taking the survey responded to
this question; of those that responded, over 88% provided an applicable response. Several themes
and key concepts emerged through the responses, with the following being the most present: savings,
self-sufficiency, carbon footprint, environment, and clean energy. More specifically, the responses
around clean energy focused on solar and photovoltaic systems.
Figure 9 – Open Ended Responses
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
22
When engaging a community for an innovative Net Zero Project community buy-in is critical. The
consideration of future impacts of the Net Zero Project are often a means to create that community
ownership. The PIIC membership was asked, “What would you like to see 10 years after the Net Zero
Project is completed?” and provided answers that influenced the formation of the Net Zero Project’s
priority areas. Approximately 77% of those taking the survey completed this question, but over 91% of
those responses were considered applicable. Key concepts emerging from the responses aligned
with Tribal values, the guiding principles of the Net Zero Project, and are reflected in the strategic paths
developed. The answers first focused on savings, particularly at the gaming operation. However, of
most importance to the community was becoming self-sufficient as a Tribal nation. This was closely
followed by ideas around economic development and sharing the successes with other stakeholder
groups.
It was important to gauge the prioritization from a community perspective when evaluating results
from the Net Zero Project. In essence, what did Tribal membership believe should be the focus of the
Net Zero Project for the highest impact to the PIIC. For this question, approximately 59% of
respondents provided an answer. Of those, 75% were considered applicable and usable for the
purposes of analysis and evaluation. Three primary focal points were present in the responses:
savings, sovereignty, and environmental stewardship. The replies being grouped into these categories
substantially align with the Net Zero Project vision and priority areas. It was abundantly clear that
the Tribal membership was first and foremost focused on financial and carbon savings from the Net
Zero Project, closely followed with a desire for the Tribe to control its energy future. These were then
grounded with a focus on the environmental impact and protecting Ina Maka (Mother Earth).
Alignment with cultural values helps for a Net Zero Project to be accepted within a community, while
also ensuring the long-term sustainability even thru leadership changes. Tribal members were asked
for their interpretation of what are the cultural values of the PIIC and provided the opportunity to convey
this in their own words. Over 62% answered this question, with almost 87% of those responses being
considered applicable. Three primary concepts were captured within the responses: a responsibility to
Mother Earth, the importance of community, and a focus on future generations. The answers were
then evaluated in relation to the core values drafted by the Tribal Council. More than 90% of the
responses fit within the seven core values identified for the Tribe, demonstrating substantial
alignment, and serving as confirmation of those values.
2.3
STRENGTHS, WEAKNESSES, OPPORTUNITIES, AND THREATS
SWOT Analysis is a common planning tool used in a variety of analyses and community planning Net
Zero Projects. The tool allows an objective evaluation of the strengths, weaknesses, opportunities, and
threats that are present in a community or organization. Once identified, a successful SWOT Analysis
realizes value in identifying ways to leverage strengths, mitigate weaknesses, capture opportunities,
and defend against threats. Figure 10 is a summary representation of the strengths, weaknesses,
opportunities, and threats facing the PIIC when focusing on a net zero solution. These were identified
through the multi-tiered input process of data collection, evaluation, and analysis. More specifically,
the individual listings within the SWOT were gathered through the document review, stakeholder
engagement, and Tribal member survey.
The SWOT focuses on community aspects of the PIIC and does not fully account for the technical
considerations. Through the multi-tiered evaluation and analysis, those components that appeared
multiple times were prioritized for inclusion in the SWOT. Those components and considerations that
were found to occur singularly in one input source may have not been included, as this often indicates
an outlier. The identification of these strengths, weaknesses, opportunities, and threats will directly
contribute to developing strategic paths that best position the community for accomplishment of their
Net Zero Project vision.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
23
Strengths are considerations which are internal--within the direct control of the PIIC--and
positive in their effect.
Weaknesses are those internal influences that are negative in their effect.
Opportunities represent positive considerations that are external to the community or
organization.
Threats are negative influences from externally controlled sources.
Figure 10 – SWOT Analysis
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
24
2.4
2.4.1
VISION, VALUES, AND GUIDING PRINCIPLES
Net Zero Project Vision
A vision statement represents a public acknowledgement of where a community or organization wants
to be in the future. More importantly, it states where the organization can be based on its own setting
and commitment. It is not a wish list of all the things that could come true under the best of
circumstances, nor is it a collection of broad goals. A vision statement focuses attention on the type
of strategic choices that will assist the organization in achieving a desired future state and helps
measure progress along the way. It is a guide to making informed decisions and strategic choices.
The vision statement for this Net Zero Project was developed by the Tribal Council based upon the
input from the stakeholder engagement efforts. It represents a Net Zero Project-specific focus, and
not an overall vision for the PIIC as a sovereign nation. The Net Zero Project Vision is as follows:
To achieve energy sovereignty and sustainability while engaging our members, fostering innovation,
honoring the past, and focusing on the next seven generations to create balance with Ina Maka.
2.4.2
Core Values
Core Values are foundational principles that stay constant regardless of changes in strategy, vision, or
mission. They are not a list of attributes toward which to strive; rather, core values pervade all levels
of a Tribal nation and its culture. Core values are foundational. They are not created; however, in some
cases they need to be clearly articulated. For Tribal nations the core values are often inseparable from
the culture and history. Many times, the values are rooted in the very existence of the tribe and are
reinforced through creation stories, history, and oral traditions. They are interwoven through
generations and are the fabric that define and hold the culture together.
Below is a list of the PIIC’s Core Values:
Bdewakantuŋwaŋ
Those born of the water
Woksape
Wisdom
Wowaȟbada
Peace or Calm
Waciŋic’iya
Self-dependence
Akhidečheča
Equality
Wowacaŋtohnake
Generosity
Oahe
Foundation
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
25
2.4.3
Guiding Principles
In addition to the Net Zero Project Vision and Core Values, a set of Guiding Principles was proposed
through work with Tribal leadership. These principles align with the core values and help to provide
guidance toward obtaining the Net Zero Project vision. They are more specific and technical in nature
than the Tribal values, while embodying those core concepts of the Nation. The solutions and strategic
paths moving forward should align with these principles.
The Guiding Principles were created through the community engagement and stakeholder processes:
the community meetings, membership survey, and stakeholder input sessions facilitated processes
and conversations with Tribal leadership furthered these ideas into principles that would guide the
development of solutions and the implementation of the Net Zero Project. These are summarized and
represented as the Guiding Principles. They seek to provide truths that will be adhered to throughout
the Net Zero Project. These Guiding Principles, referenced in Figure 11, are Net Zero Project-specific;
however, they may be in alignment with other Tribal initiatives as well.
Figure 11 – Guiding Principles
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
26
ENERGY BASELINE AND SYSTEM STUDY
3.1
PROFILES OF UTILITY SERVICE AND CONSUMPTION
Formulation of a Net Zero Plan is promulgated on a basic understanding of the consumption profiles
of purchased utilities and fuel. Purchased utilities include electricity and natural gas and represent the
largest categories of energy consumption within the PIIC. Profiles have been developed from the 2019
usage for three general categories:
Buildings and Purchased Utilities
Fleet Vehicles
Water
Buildings are primarily located in three areas: Prairie Island, Mount Frontenac Golf, and Oyate Place.
The highest concentration of buildings and, correspondingly, the highest use of energy is within Prairie
Island. Oyate Place is a property being developed at the junction of Highway 61 and 316 and is the
location of an existing senior living center, Tinta Wita Tipi. Mount Frontenac Golf is the golf course
property southeast of Red Wing.
Dakota Electric Association (DEA) provides electric service to Prairie Island. Xcel Energy provides
electric service to Mount Frontenac Golf and natural gas service to Prairie Island and Oyate Place.
Purchased fuels include propane, gasoline, and diesel. Propane is used at Mount Frontenac Golf and
some residences on Prairie Island. The gasoline and diesel fuel consumption of both vehicle fleets
used by the TIRC and Tribal Government are also included in the energy baseline.
3.1.1
2019 Base Year
The calendar year 2019, representing the last year not affected by restrictions due to the COVID-19
pandemic, was selected as the base year of the Net Zero Project. The base year consumption includes
purchased utilities and fuels used by buildings and vehicle fleets of the Tribal government and TIRC.
3.1.1.1
Buildings and Purchased Utilities
Respective consumption is further delineated by major user groups: Casino-Hotel Resort, Tribal/Public
Buildings, Residential, and Mount Frontenac Golf.
Figure 12 – Major Energy User Groups
Casino-Hotel Resort
Casinos 1 through 8
Casino Offices
Event Center
Family Fun Center
Water Park
Concert Venue
Marina
RV Park
Warehouse and Maintenance
Tribal/Public Buildings
Community Center/Clinic
Elder Center
Public Service
Administration
Buffalo Exhibit
Softball Fields
Pow Wow Grounds
Water and Wastewater
Dakota Station and Car Wash
Tinta Wita Tipi (at Oyate Place)
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
Mount Frontenac Golf
Clubhouse
Main Maintenance Buildings
Remote Course Maintenance
27
The residential user group is located on the Prairie Island Reservation in three general areas:
Lower Island in proximity to the TIRC and Tribal Government buildings;
Mato Circle; and
Dakota Circle.
Mato Circle and Dakota Circle are located generally northwest of the Lower Island residences along
County 18 (Prairie Island Boulevard).
Utility and energy consumption of TIRC, Tribal/Public Buildings and Mount Frontenac Golf is based on
utility billing data. Residential consumption is based on average consumption patterns for Minnesota
households. The average is applied to number of residences on Lower Island (46
residences), Mato Circle (26 residences) and Dakota Circle (24 residences) to yield an annual total
estimate of residential utility consumption: electric, natural gas and propane. The propane estimate
for residential consumption is based on a count of propane tanks in the respective residential areas:
Lower Island, 19; Mato Circle, 3; and Dakota Circle, 8.
Figure 13 presents a summary of energy and purchased utilities in support of building operations,
specifically electricity, natural gas, and propane. TIRC accounts for nearly 88% of base year electric
consumption and 89% of base year natural gas consumption. Approximately 10% of base year electric
consumption and 6% of natural gas consumption are by Tribal/Public Buildings.
Figure 13 – Base Year Utility Consumption by User Group
User Group
Casino-Hotel Resort
Tribal/Public Buildings
Residential
Mount Frontenac Golf
Total
Electricity
kWh
28,503,129
3,186,341
712,848
108,440
32,510,758
Natural Gas
Therms
1,175,144
80,881
62,800
1,318,825
Propane
Gallons
31,368
3,360
34,728
Figures 14 through 16 illustrate the annual consumption patterns of the respective user groups for
electricity, natural gas, and propane.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
28
Figure 14 – Annual Consumption Patterns – Electricity
Figure 15 – Annual Consumption Patterns – Natural Gas
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
29
Figure 16 – Annual Consumption Patterns – Propane
3.1.1.2
Fleet Vehicles
Total Base Year (2019) fuel consumption of the vehicle fleets is 52,296 gallons of gasoline and 9,446
gallons of diesel. Figure 17 provides a breakdown of fuel consumption by application (street and nonroad) and primary user (TIRC and Tribal Government). Virtually all diesel fuel is consumed by non-road
vehicles.
The vehicle fleet of TIRC accounts for approximately 66% of base year vehicle fuel consumption,
gasoline, and diesel fuel. The TIRC fleet consists of 28 street vehicles (sport utility vehicles, pick-up
trucks, dump trucks, vans, and shuttle buses) plus non-road vehicles (golf carts, skid loader, payloader,
lawnmowers, street sweeper, and Spirit of the Water yacht). The remaining fuel, approximately 33% of
gasoline and diesel fuel, is consumed by the Tribal Government fleet. The Tribal Government vehicle
fleet consists of 37 street vehicles (cars, police vehicles, vans, sport utility vehicles, pick-up trucks, fire
truck and shuttle bus) plus non-road vehicles (tractor, skid loaders, all-terrain vehicles, mowers, and
boats).
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
30
Figure 17 – Base Year Fuel Consumption by Vehicle Fleet
Gasoline
TIRC
Street
Non-Road
Sub-Total
Tribal Government
Street
Non-Road
Sub-Total
Total
Diesel
in gallons
TOTAL
29,525.8
2,061.4
31,587.2
203.9
9,170.9
9,374.8
29,729.7
11,232.3
40,962.0
17,365.8
3,343.7
20,709.5
52,296.7
71.7
17,437.50
3,343.70
20,781.20
61,743.2
71.7
9,446.5
The maintenance department is the dominant user of the gasoline and diesel fuel consumed by the
TIRC vehicle representing 40% of the total fuel used. Other major fuel users include transportation,
marina, valet, and security representing 23%, 15%, 12% and 9% of fuel consumed by TIRC annually.
The Tribal Government vehicle fleet shows a similar pattern with consumption dominated by four
departments:
Police
Roads & Parks
Buffalo Exhibit
Family Services
42.9%
16.9%
10.9%
8.7%
Figures 18 and 19 provide a general comparison of consumption for the fleet of both the PIIC Tribal
Government as well as the Treasure Island Resort & Casino.
Figure 18 – General Comparison of PIIC Tribal Government Vehicle Fleet Fuel Consumption
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
31
Figure 19 – General Comparison of Treasure Island Vehicle Fleet Fuel Consumption
3.1.1.3
Water
Water is complementary to energy and associated emissions. Conservation and management of water
consumption preserves a resource but also has implications for CO2 emissions. Energy, primarily
electricity, is required for production, treatment, and delivery of water to the end-user for
consumption. Additional energy (electricity, natural gas or propane) is consumed to produce domestic
hot water and to heat water (natural gas) used in heating systems within buildings. Subsequently,
energy is required for wastewater treatment.
The water plant has produced an annual average of 106.03 million gallons over the period of calendar
year 2018 through 2020. See Figure 20.
Figure 20 – Prairie Island Water Production
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
32
The TIRC consumed approximately 92% of water production, or 97.71 million gallons, as
shown in Figure 21. The remaining 8% is presumed to be system losses and consumption by
lower island residences. Residences at Mato Circle and Dakota Circle have private wells and
are not served by the PIIC water plant.
Figure 21 – TIRC Water Consumption
3.1.2
Base Year Consumption and Emissions Benchmark
For the purpose of this initial analysis, net zero is measured in the context of CO2 emissions. Factors
for CO2 emissions are presented in Figure 22. The factors shown for fuels in Figure 22 are default CO2
emission values issued by the EPA. The factors for electric service were provided by the incumbent
electric utilities: DEA and Xcel.
Figure 22 – CO2 Emissions Factors
Type of Fuel
Natural Gas LBS CO2/Therm
CO2 Emissions Factor
11.71
Propane LBS CO2/gallon
12.38
Gasoline LBS CO2/gallon
Diesel LBS CO2/gallon
Electric Service LB CO2/MWh
Dakota Electric Association
Xcel Energy
19.42
22.58
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
91.26
576
33
These factors are applied to the corresponding consumption of natural gas, propane, gasoline, diesel,
and electric service to yield Base Year (2019) emissions benchmark of CO2. These factors are also
subsequently applied to changes in consumption associated with Net Zero measures for a quantifiable
change in CO2 emissions relative to the base year emissions benchmark.
3.1.2.1
Buildings and Purchased Utilities
Figure 23 shows the Base Year (2019) CO2 emissions benchmark associated with the energy
consumption of the PIIC buildings. Total CO2 emissions are approximately 64.82 million pounds when
considered on the basis of fuel and electric service. Electricity is the predominant component of CO2
emissions, about 75%, followed by natural gas and propane: 24% and 1%, respectively.
Figure 23 – Base Year (2019) CO2 Emissions Benchmark by User Group and Utility
User Group
Casino-Hotel Resort
Tribal/Public Buildings
Residential
Mount Frontenac Golf
Total
Electricity
42,982,718
4,805,002
1,074,974
84,583
48,947,277
Natural Gas
13,760,936
947,117
735,388
15,443,441
Propane
388,336
41,599
429,935
TOTAL
54,743,654
5,752,119
2,198,698
126,182
64,820,653
Figure 24 also shows the Target Year (2023) CO2 emissions benchmark associated with the energy
consumption of the PIIC buildings. Total CO2 emissions are approximately 18.89 million pounds when
considered on the basis of fuel and electric service, natural gas is the predominant component of CO2
emissions, about 81.7%, followed by electricity and propane: 16% and 2.3%, respectively.
The difference between Base Year (2019) and Target Year (2023) electricity emissions is due to the
aggressive carbon reduction procurement and/or generation strategies of the PIIC’s serving electric
utilities, which are reducing their portfolio’s CO2 emissions by 94%.
Target Year (2023) emissions benchmark attributable to the user groups follow the same general
pattern as consumption, since CO2 emissions is the simple product of consumption multiplied by a
constant for the fuel or utility service. The Casino-Hotel Resort contributes about 86.6% of total CO2
emissions.
Similarly, Tribal/Public buildings account for 6.6% of total CO2 benchmark emissions. The Residential
user group and Mount Frontenac Golf represent 6.3% and 0.6% of CO2 benchmark emissions,
respectively.
Figure 24 – Target Year (2023) CO2 Emissions Benchmark by User Group and Utility
User Group
Casino-Hotel Resort
Tribal/Public Buildings
Residential
Mount Frontenac Golf
Total
Electricity
2,601,196
290,786
65,055
62,461
3,019,498
Natural Gas
13,760,936
947,117
735,388
15,443,441
Propane
388,336
41,599
429,935
TOTAL
16,362,132
1,237,903
1,188,779
104,060
18,892,874
For the purposes of this report, the Target Year (2023) CO2 emissions benchmark by user group and
utility total (18,892,874 lbs) is utilized moving forward as a key metric for the Net Zero Project
emission reduction strategies highlighted in Sections 4 and 5.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
34
3.1.2.2
Fleet Vehicles
Total Base Year (2019) CO2 benchmark emissions attributable to the operation of fleet vehicles are
about 1.2 million pounds. The tabulated emissions, shown in Figure 25, are the product of reported
consumption by the fleet vehicles and the respective emission factor for gasoline and diesel provided
by the EPA.
Figure 25 – Base Year (2019) CO2 Emissions by Vehicle Fleet
Gasoline
TIRC
Street
Non-Road
Sub-Total
Tribal
Government
Street
Non-Road
Sub-Total
Total
3.1.2.3
Diesel
(Lbs. of CO2)
TOTAL
573,519
40,041
613,560
4,605
207,102
211,707
578,124
247,143
825,267
337,319
64,949
402,268
1,015,828
1,619
338,938
64,949
403,887
1,229,154
1,619
213,326
Net Zero Emissions Benchmark
Total Net Zero CO2 emissions inclusive of electricity, natural gas, and propane to support residences
and buildings, and gasoline and diesel used by vehicle fleets are 20,122,028 lbs (18,892,874 lbs
buildings emissions + 1,229,154 lbs vehicle fleet emissions). See Figure 26.
Electricity
3,019,498 lbs
Natural Gas
15,443,441 lbs
Propane
Vehicle Fleet
429,935 lbs
1,229,154 lbs
As stated previously, electricity emissions (3,019,498 lbs) reflect the Target Year (2023) when the
aggressive utility decarbonization efforts are realized.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
35
Figure 26 – Total Net Zero CO2 Emissions Benchmark
Electricity emissions reflect the target
year CO2 benchmark (2023) when utility
decarbonization efforts are realized as
referenced in Figure 24.
3.2
ENERGY ASSESSMENTS
The baseline energy profiles, and consumption data provide the foundation for evaluating potential
energy management and emission reduction measures. This energy assessment process also
included a review of the condition and operation of energy-intensive equipment found in heating and
cooling systems, domestic hot water systems, laundry equipment, lighting and building controls.
The Casino-Hotel Resort was a primary focus of the assessment process, reflecting its predominant
contribution to the Net Zero emissions benchmark. Other buildings included in the assessment
process are:
Community Center/Clinic
Prairie Island Administration
Dakota Station
Elder Center
Mount Frontenac Clubhouse
Public Safety Building
Residences
Tinta Wita Tipi Senior Living Facility
Note that some facilities such as Tinta Wita Tipi and private residences were not accessible given
health considerations during COVID-19. In these instances, the assessment process was a desk review
of potential measures based on consumption data and energy performance standards for type,
function, and location of buildings.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
36
NET ZERO TARGET – INVESTIGATED MEASURES
4.1
ALIGNMENT WITH COMMUNITY AND STAKEHOLDER ENGAGEMENT
The Net Zero Team identified 46 measures for incorporation into the Net Zero Project. The measures
are grouped within the three topical areas: energy efficiency, electrification, and renewable generation.
Based on the results of community outreach conducted throughout the initial months of the Project,
these measures are consistent with the ideals and culture of the PIIC as it relates to energy
conservation and use.
4.2
ENERGY EFFICIENCY
Energy efficiency has a twofold effect for the Net Zero Target. Energy efficiency measures reduce
Community consumption and provide a direct corresponding reduction of CO2
emissions. Correspondingly, this reduction of energy use translates to a potential reduction in required
local renewable generation and/or electrification measures and equipment. Thus, by deploying energy
savings strategies first, the capital required for development of renewable generation assets is
reduced. For simplicity in reporting, energy efficiency measures have been aggregated and
organized by three major user groups:
1. Casino-Hotel Resort
2. Tribal Buildings
3. Residences
4.2.1
Casino-Hotel Resort
4.2.1.1
Kitchen Hood Controls
Kitchen makeup-air units (MAU) support fresh air ventilation by providing conditioned, constant
volume air in the kitchen areas to make up for the air lost due to exhaust fans. The exhaust fans also
provide a constant volume exhaust of air from the kitchens to maintain required ventilation. The site
has a total of six MAUs located on the casino roof with the following assumptions on fan motor
horsepower (HP) size:
MAU-1: 5 HP
MAU-2: 7.5 HP
MAU-3: 5 HP
MAU-4, MAU-5, & MAU-6: 3 HP each
The site also has a total of 24 kitchen exhaust hoods located on the casino roof serving different dining
areas within the building. The MAUs and exhaust fans have a CAV (Constant Air Volume) fan, which
supplies conditioned air to the space in fixed quantity, regardless of the air or cooling demand of the
space. Also, the cooling demand of the space fluctuates due to the external heat gain (i.e., solar heat
gain and conduction from surrounding walls) which vary throughout the day. The CAV fan operates
at a constant speed to provide static air pressure to the system. The CAV fan is typically chosen as a
design requirement to deliver static pressure for the air ventilation rate(s) in the room and cooling on
the hottest day. Fan speed and associated energy consumption can be reduced because the
ventilation rate depends on the occupancy or cooking schedule, and because the cooling demand will
be lower relative to the hottest day for the remainder of the year, there is an opportunity to reduce the
fan speed to further save energy.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
37
The recommendation is to optimize the operating hours of exhaust fans serving kitchen hood based
on operations and planned occupancy in the room. The type of cooking operations can be identified
using flow proving switches on the gas supply, occupancy sensors, space temperature sensors, and
smoke/CO2 sensors. This will reduce fan running hours and increase energy savings as a
result. Correspondingly, this extends to all MAUs serving the same space since reducing exhaust will
allow a reduction in required make-up air introduced into the space.
The Net Zero Team also recommends retrofitting the CAV fans in both the Kitchen MAUs
and exhaust fans inside the kitchen hoods with sensors and variable frequency drives (VFDs). The
sensors will modulate fan speed according to cooking activity and occupancy to achieve both space
temperature set point and proper volumes of outside air ventilation. With this change, the MAUs
and exhaust fans will run at 100% speed when extensive cooking is taking place and
at reduced capacity with medium cooking activity. Since fan energy use is proportional to how much
pressure a fan creates to maintain flow, energy savings is realized when the fan’s set
point is lowered as a result of reduced need.
Better control of the kitchen hoods, as recommended, will decrease electric consumption
by approximately 48,000 kWh annually. Key factors and assumptions driving energy savings are:
Load factor of all units supply fan motor was assumed to be 80% and efficiency at 80% for
baseline condition. Efficiency was assumed at 85% after addition of VFDs to the existing
motors. An addition of VFDs would improve motor performance, and thereby increase
efficiency.
Each individual exhaust fan motor HP was assumed to be 1 HP.
Baseline (current) condition: units are operating an average of 15 hours daily and on all 365
days at full (or 100%) fan motor speed.
EE measure condition: units are operating an average of 10 hours daily and on all 365 days at
variable fan motor speed, which depends on type of cooking activity being performed.
This measure will result in an estimated savings of $3,517 annually. The capital cost of this measure
is estimated at $20,000.
4.2.1.2
Monitoring-Based Commissioning or Equivalent
The site audit presented various energy conservation opportunities to improve the existing equipment
performance and help the site conserve and save energy. Monitoring-based commissioning (MBCx) is
the integration of three components: permanent energy monitoring systems, real-time energy analysis,
and ongoing commissioning. Since, MBCx is an ongoing performance analysis of an operational
building that provides real-time equipment performance information to the building operators, it will
allow the site to track its energy consumption, detect faulty equipment operations, and identify
unusual energy or power consumption patterns as they occur.
An MBCx platform automatically analyzes data from automation systems, metering systems and other
smart devices to identify issues, patterns, deviations, faults and opportunities for operational
improvements and cost reduction. MBCx will help operators find important information in the data
produced by their equipment systems, discovering the invisible issues, quantify the opportunities and
form a management feedback loop. Many common issues such as negative pressurization, incorrect
sensor readings, valves not stroking properly can be identified through MBCx. Implementation of
occupancy schedules and controls improvement can also be done through MBCx.
MBCx could be extended to the other facilities to provide additional insights. Through discussions with
the facilities Net Zero Teams, it has been identified that a controls upgrade is planned for various
facilities outside of TIRC. By incorporating adjacent facilities into an MBCx platform, the selected
vendor could provide additional insights to optimize energy spend and to ensure the controls systems
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
38
continue to operate as intended during the warranty period and beyond. MBCx could also be utilized
to provide a community facing dashboard to allow members of the public to see real time energy
savings to track the success of the Net Zero Project if desired.
MBCx is expected to reduce electric consumption by approximately 1,248,000 kWh with a
corresponding reduction in operating expense of $90,000 annually. MBCx is a subscriptionbased service carrying an estimated annual fee of $28,320 on a 60-month contract.
4.2.1.3
Lighting
The Net Zero Team recommends replacing all linear fluorescent lamps with high-efficiency linear LED
tube lamps and replacing CFL lamps with LED screw-in lamps. These lamps offer longer life and better
color rendering and will result in an approximate 60% reduction in average fixture wattage. This
reduction in wattage will save approximately 1.36 million kWh saved annually and reduce operating
expense of the Casino-Hotel Resort by $131,000. The estimated cost of these lighting improvements
is approximately $325,000, yielding a simple payback of less than 2.5 years.
4.2.1.4
Lighting Controls
In addition to the LED lamp conversion recommended above, the Net Zero Team also recommends
installing occupancy sensors and in all common area spaces and hallways of the Casino-Hotel Resort.
The sensors and controls should be configured based on type of space, area (square feet), number of
fixtures and required minimum light levels. This type of control will allow LEDs to reduce their output
by 25-50% on average, with low-traffic spaces able to shut-off entirely.
The Net Zero Team estimates the approximate annual energy savings achieved by lighting controls to
be approximately 226,000 kWh and with an associated expense savings of $21,700. The estimated
cost of the lighting controls is approximately $178,000.
4.2.1.5
Exterior Lighting
The Net Zero Team recommends replacing all parking lot and street lighting fixtures with highefficiency LED pole-mounted fixtures. These LED fixtures can provide much higher brightness levels
and cutoff designs for reduced environmental impact, while operating at 50% less wattage. A full
lighting design survey should be performed using light level analysis software. This tool will provide the
correct cutoff requirements and lighting levels needed to efficiently light the intended areas.
The Net Zero Team expects the exterior lighting measures to save approximately 51,000 kWh and
nearly $5,000 in annual electric expense. The estimated cost of the exterior lighting measure is
$47,000.
4.2.1.6
Ventilation Energy Recovery
The requirement to ventilate and exhaust air from occupied spaces imparts an energy load on the
HVAC systems serving the TIRC complex. This demand can be significant given the extremes of the
local climate. The casino has currently installed three (3) rooftop Energy Recovery Units (ERU) that
provide ventilation and exhaust air service to the Bingo Hall, Casino Floor #1 and Casino Floor #2. The
Units handle approximately 54,000 cfm of air and include Energy Recovery Wheels (ERW) to transfer
heat from the warm exhaust air to the cold ventilation air during the winter season. This process is
reversed during the summer season, where heat is transferred from hot ventilation air to the cool
exhaust air. The process in the hotel rooms is much simpler. Fans exhaust approximately 41,800 cfm
of air from occupied spaces and specialized air handling units to heat or cool the make-up ventilation
air. In these systems, no heat is recovered and therefore, there is no transfer of air between the
ventilation and exhaust air streams.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
39
Ventilation energy recovery is often the first strategy implemented in mechanical systems when energy
and emissions are of concern. The equipment is commonly 50% to 65% effective in recovering and
transferring air between air streams. This is a direct reduction in the energy required to heat and cool
ventilation air. This equipment also has the secondary benefit, when the ventilation system is
sufficiently distributed throughout the facility, the resulting outcome is a reduced overall size of the
central heating and cooling plant.
The proposed solution takes advantage of ventilation energy recovery in two key areas of the facility.
First, the three (3) existing rooftop ERUs serving the Bingo and Casino areas are refurbished for
improved performance. The wheel media used to transfer energy between air streams is replaced with
new media with low odor carryover properties. All bearings, belts and drive motors are replaced, and
the equipment’s controls are updated and integrated into the Building Automation System (BAS).
Second, new ERUs are installed on all three hotel towers to recovery heat from hotel room bathroom
exhaust air. The existing exhaust fans are removed, and new rooftop ductwork is routed to the ERUs.
The pre-heated air from the ERUs is then ducted to the existing hotel make-up air handling units.
Modern controls are provided for these systems and are integrated into the BAS.
The estimated cost of these measures is $787,000. These measures are expected to reduced annual
operating expense by approximately $95,000.
4.2.1.7
Water Measures
Measures for reducing water consumption will provide associated savings in reduced energy
consumption for production of domestic hot water and reduced electric consumption for delivery of
water to point of use. Water-energy measures identified for the Casino-Hotel Resort include low flow
showerheads, faucet aerators, pre-rinse spray valves, and EnergyStar ice machines. The aggregate
effect of these measures is the reduction of natural gas and electric consumption by 44,800 therms,
and 12,800 kWh, respectively; and 8.3 million gallons of water consumption. The estimated
capital cost of these water measures is $59,000.
4.2.2
Tribal Buildings
4.2.2.1
Lighting
Lighting in Tribal and community public buildings was assumed to comply with ASHRAE 90.1 standards
of Lighting Power Density. Considering the size and function of the respective buildings (office,
clinic, sports, etc.) the lighting power density varies from 0.9 watts/sq ft to 1.2 watts/sq ft. The Net
Zero Team assumed that approximately 10% of fixtures and lamps had already been converted to LED
during routine burnout maintenance. From this basis the Net Zero Team estimated the annual energy
consumption for lighting of the various Tribal and community public buildings (Community
Center/Clinic, Elder Center, Public Safety, Tinta Wita Tipi, Dakota Station, Administration and Mount
Frontenac Clubhouse) at approximately 603,000 kWh. The Net Zero Team recommends replacing all
linear fluorescent lamps with high-efficiency linear LED tube lamps, and CFL lamps with LED screw-in
lamps, which will result in an approximate 30-40% reduction in average fixture wattage. The reduction
in wattage is calculated using current ASHRAE 90.1 LPD standards. This reduction in wattage will
result in nearly 35,400 kWh saved or $3,400 in annual operating expenses. Overall, the Tribal and
community building lighting retrofits will result in a 4.4-year measure payback with an estimated cost
of $15,000.
4.2.2.2
Water Plant
Potable water is used for irrigation of TIRC grounds and the ballfields. The water is pumped
from aquifers and treated to potable standards at the water treatment plant.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
40
A recommended water saving measure is to use treated water from the wastewater treatment plant as
a source for irrigation. Use of treated wastewater has multiple benefits including reduced freshwater
use, reduced freshwater pumping and treatment costs, reduced energy use, and reduced treated
wastewater discharges into the Mississippi River. This measure may save approximately 58,000 kWh
and 38 million gallons of potable water each year. The Net Zero Project will entail installing new piping
and reconfiguring the wastewater treatment plant water distribution system to convey treated
wastewater to irrigation locations. The estimated cost of this measure is $350,000.
4.2.3
Residential
4.2.3.1
Energy Report and Monitoring
A key element of the Net Zero Project is encouraging changes in behavior at both the Tribal and
individual member level in a manner that reduces and sustains lower carbon emissions. The Net Zero
Team recommends implementation of a Home Energy Report (HER) program. Such programs provide
utility customers with reports that compare their usage against others as a means to track individual
consumption patterns but also to allow identification of additional opportunities to reduce energy use.
A HER program simply reporting Tribal members energy consumption is not likely to be practical, but
one that includes decarbonization messaging with custom usage information and various energy
savings tips may be possible. This type of program could have an implementation cost $100,000
but has the potential of reducing CO2 emissions by 22,000 lbs. of CO2 directly and could be used to
encourage adoption of other energy savings and/or carbon reducing technologies for additional future
savings.
4.2.3.2
Water Measures
Reducing water consumption often results in a corresponding reduction of energy consumption.
Faucet aerators for kitchen and bathrooms and low flow showerheads are low-cost measures to reduce
water consumption. Each residence is expected to reduce energy expense by about $50 per year
saving over 17,000 gallons of water over the 10-year life of the measures.
The total cost of the Net Zero Project is estimated to be $11,000.
4.3
RENEWABLE GENERATION
The Net Zero Team evaluated potential generation from various renewable technologies, considering
known Tribal cultural and historical sites, resource availability, environmental, land-use, and electrical
distribution system constraints. By reviewing the renewable technologies based off historical data in
the region, the Net Zero Team was able to filter out non-cost-effective technologies and focus on only
the most beneficial renewable Net Zero Projects. A summary of the resource assessment is included
below.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
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4.3.1
Solar
Figure 27 – NREL Solar Irradiance Map
The amount of solar energy
produced in a specific
geographical area depends
on the average daily solar
irradiance. Solar irradiance
is defined as the power per
unit area (typically in Watts
per square meter) received
from the sun. More
generally, it is a factor of
how much solar energy is
received over a pre-defined
area. PV Net Zero Projects
that receive a higher
amount of annual irradiance
produce a higher amount of
energy.
The PIIC Reservation receives a moderate solar irradiance. According to NREL’s geospatial data map
(Figure 27), the average daily irradiation averages between 0.371612 kWh/sq ft and .408773 kWh/sq
ft. Additional validation for these daily irradiation levels comes from the NREL Solar Prospector website
which calculates a daily average solar irradiance value of 0.396696 kWh/sq ft. In terms of energy,
these figures indicate that every day for every square foot between .37 and .41 kWh of energy in the
form of sunlight hits the earth.
While solar arrays in Minnesota do not produce as much electricity as in the Southwestern United
States, total irradiance is only one consideration. There are additional constraints and factors involved
including state incentives, utility regulations, and interconnection requirements that also contribute to
the effectiveness of solar power. These factors are further discussed in the interconnection discussion.
4.3.2
On-Shore Wind
Wind power production is directly related to the average wind speed at the location of installation.
Standard wind turbines typically reach nameplate power production at a wind speed of 22 mph to 27
mph. Because power production scales exponentially with wind speed, higher wind speeds produce
power orders of magnitude greater than that produced at lower wind speed (see Figure 28).
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
42
Figure 28 – General Electric (GE) 2.5MW, 328’ Wind Turbine Power Profile Curve
Determining this average annual wind speed is essential when creating the annual production system
model. Without accurate wind speed data, it is impossible to accurately forecast the yearly production.
For this reason, it is common for utility-scale wind Net Zero Projects to collect one to three years’ worth
of hourly wind speed data at the site location. This is achieved by installing a meteorological “met”
station on a pole at the rotor height of the proposed wind turbine. The met station will record wind
speeds throughout the day and upload this information to a server for use in modelling wind
production.
Absent this level of analysis and data collection, alternative methods exist to collect hourly wind speed
data. The Net Zero Team utilized a variety of sources in determining the average wind speed at both
ground level and a typical 328 ft. rotor height. The following section describes the methods for wind
data collection.
4.3.2.1
Global Wind Atlas
The Global Wind Atlas is an online mapping tool developed by the World Bank in conjunction with the
Department of Wind Energy at the Technical University of Denmark. It was created to help policymakers
and investors identify potential high-wind areas for wind power generation anywhere in the world. The
Net Zero Team chose the Global Wind Atlas as a data source based on its validation by real-world
measurements, other wind atlases, and mathematical calculations.
Based on the Global Wind Atlas model, the average wind speed for the 10% windiest areas has been
calculated at 16.8 mph at a rotor height of 328 ft.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
43
Figure 29 – Average Wind Speed Map of the PIIC and Surrounding Area (Global Wind Atlas)
4.3.2.2
NREL Wind Prospector
The NREL Wind Prospector is an online mapping application built on the OpenCarto. The NREL Wind
Prospector is known as one the industry benchmarks for preliminary wind speed analysis.
Wind Prospector offers a variety of data outputs depending upon the conditions chosen by the user.
The most pertinent data for the purpose of modelling wind production are the wind speeds at a variety
of heights and the wind class of the island. The Wind Prospector data indicates that the average wind
speed on the island varies between 13.4 to 15.6 miles per hour at a height of 328 feet. At this wind
speed, standard wind turbines output power at a 35% to 50% of their nameplate capacity. This lack of
wind speed, plus the lack of local utility incentives, suggests that wind power is not cost-effective for
the PIIC. Tribal Members also raised concerns about conventional wind turbines and the potential risk
of killing eagles which are plentiful in this segment of the Mississippi River.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
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Figure 30 – Average Wind Speed Map of the PIIC and Surrounding Area (NREL Wind Prospector)
4.3.3
Hydroelectric Power
The proximity to several bodies of water and river systems makes the PIIC an interesting location for
possible hydroelectric power production. When exploring the viability of this type of renewable
generation, several different methodologies were considered. Storage systems, using dams and
reservoirs, could be dismissed immediately because of intense capital cost and environmental impact.
Low-head, run-of-the-river generation systems where little to no storage would be required, were
looked at more closely. Ultimately these were determined to be less viable when compared to other
renewable resources such as solar for the following reasons:
Extremely low head pressures - The elevation change between any two points on the river
within the PIIC is low and presents a significant challenge in siting inlets and turbines that
establish enough pressure to generate energy in significant amounts.
Regulatory and permitting costs - While FERC has worked to make the licensing and license
exemption processes more efficient for developers of small-scale hydropower systems, there
are significant challenges and fees associated with hydroelectric licensing. Additionally, there
are additional areas of jurisdiction that require permitting and licensing-related studies to be
performed. The upfront costs associated with the licensing and/or the license exemption
processes are considerable.
Construction expense - The cost of building hydro-generation can vary greatly and is hard to
estimate without extensive and expensive studies. The cost of developing a reliable estimate
with sufficient detail is not justifiable considering the likely benefits, or lack of, from
hydroelectric generation in this area.
The cost of transmission - The construction of power lines to move electricity generated nearby
to load centers or distribution systems on the PIIC would face significant geological challenges.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
45
These challenges in engineering and construction are likely to add significant expense above
and beyond the benefit from constructing a generation facility.
While the flow rate of the river near the PIIC is considerable, and the energy associated with it, the
ability for the PIIC to harness that energy is severely limited.
4.4
ENERGY STORAGE
The Net Zero Team evaluated energy storage as a supplemental technology used to complement
renewable energy and provide backup power to the PIIC. Energy storage offers both financial and
resiliency opportunities by interacting with both local generation and the larger utility grid. Many energy
storage technologies are available including sodium-sulfur, lithium-ion, lead-acid (flow), flywheel, and
pumped hydro. For this study, we focused on lithium-ion technology. This is due primarily to the
maturity and track record of the technology and its effectiveness in renewable and backup power
applications. It should be noted while lithium-ion is commonly installed in many applications, statistical
data indicates lithium-Ion batteries are struggling to meet the demands of utility scale grids.
4.4.1.1
Lithium Ion (Li-ion)
Lithium-ion battery systems (shown in Figure 31) are among the most widely used grid-scale energy
storage technologies deployed today. Li-ion boasts the greatest power and energy density of any close
competitor in the market, and there has been a dramatic decrease in installed prices over the last ten
years. This has led to Li-ion becoming the most popular and economic Battery Energy Storage System
(BESS) technology installed for grid support and renewable energy production augmentation. Li-ion
installations benefit from a wide selection of vendors with robust supply chains, as well as experienced
contractors and service professionals to build and operate the systems. They are also a known quantity
in terms of long-term performance, degradation, and full-lifecycle system benefits.
Figure 31 – A123 Systems, Inc. Lithium-ion Containerized BESS
4.4.2
Conclusion
Based on this preliminary analysis, it was found that solar energy is the most effective renewable
resource for the PIIC. Solar arrays have the least engineering and construction complexity, the lowest
barrier to entry for interconnection, and there is enough solar irradiance available to make the solar
financially viable.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
46
4.5
INTERCONNECTION OPTIONS
Meeting the Community’s net zero goals requires involvement of both DEA and GRE. DEA and GRE are
responsible for system performance and, as a result, must approve the PIIC to export renewable energy
onto the grid. Additionally, both companies have technical and financial requirements that must be
met in order to interconnect. DEA has presented a number of interconnection options for consideration
by the PIIC. These options and programs are presented below.
4.5.1
Net Metering
Net metering is a billing mechanism that credits solar energy system owners for the electricity they
add to the grid. Net metering allows a customer to offset their total electrical consumption via the total
power their solar system produces. For example, if a customer consumes 100kWh of power over a 30day timeframe, but they produce 100kWh of solar generation over the same timeframe, their energy
bill is zeroed out (minus any associated fees or standby charges). Net metering lets a customer
produce more solar than their facility can consume while still receiving financial credit for the overall
production.
DEA has a net metering program available for solar arrays with capacity less than 40kW. This program
applies on a per-service basis. DEA typically only allows one service (and therefore one net metering
program) per site. However, since the TIRC has expanded over time and has multiple utility meters,
there is an opportunity to utilize multiple net metering programs. A potential option would be
constructing a large canopy or rooftop array and then interconnecting separate 40kW slices at
different electrical service switchgear units. This method of breaking up the array would allow the PIIC
to take full advantage of multiple net metering interconnections. Alternatively, smaller residential
installations would also be eligible for net metering.
Since net metering allows a customer to offset their electrical bill at the same rate they pay for
electricity, net metering can be a very lucrative program for the PIIC. Non-net metering programs
typically require a customer to sell energy at wholesale prices, which are much lower than net metering
prices. However, non-net metering programs can still be profitable depending on capital costs and
other incentives. These programs would be applied to installations larger than 40kW (as net metering
is only available for system sizes up to 40kW) and are described in the following sections.
4.5.2
Self-Generation
Under the self-generation interconnection option, the PIIC would design, construct, own, and operate
local renewable generation with energy storage. Renewable Net Zero Projects such as rooftop, canopy,
or ground-mount solar would generate electricity that would be immediately consumed. As an example,
if the TIRC were to draw 1MW of power during the day and a solar array produced 600kW, the TIRC
would draw 600kW from the solar array and 400kW from the utility (DEA). In this example, when 60%
of the energy consumption is served with solar power and energy storage and, all things being equal,
the utility bill would be reduced by 60%.
There are two major limitations to this type of installation. The first is that the solar system must be
sized for the load of the TIRC. Since net metering isn’t allowed under this scenario, any excess solar
power that is produced and exported to the grid would be purchased at wholesale rates. This could be
mitigated by installing utility scale energy storage to store excess renewable energy generated at that
time and used later when electricity prices are high. If this mitigation is not implemented, the purchase
of energy at wholesale rates is unlikely to make the project financially viable, so unless energy storage
is used in conjunction with generation, the solar system will need to be sized to minimize export and
maximize local consumption. In this scenario, the system sizing will likely be based on the minimum
electrical draw. That is to say, the nameplate kW capacity of the solar array should not be larger than
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
47
the minimum load drawn during peak solar hours. Financial modeling of these options will take place
in Phase 2 of the study.
The second limitation is that DEA requires the PIIC to pay a standby charge. Despite generating some
of their own power, on-site generation may be intermittent based on weather conditions or other
causes. Additionally, the PIIC’s generation may trip offline. Therefore, the PIIC will still need grid
connectivity to ensure their electrical needs are met. A standby charge is used when the utility is
required to keep additional power on “standby” to offset generation intermittency. Because DEA would
be responsible for providing this standby power, they will require the PIIC to pay a fee for the service.
This standby charge is proportionate based on the amount of power that DEA must have in reserve to
offset generation losses. The standby fee must be included in the financial model when calculating
profitability and payback.
4.5.3
DEA 5% Renewable Program
DEA has a contractual provision with GRE that allows the cooperative to acquire up to 5% of their
annual system energy from renewable resources either owned by DEA or through a Power Purchase
Agreement (PPA). The precise value of renewable generation in terms of $/kWh is yet to be determined
but is expected to be higher than selling power back to GRE at avoided cost (wholesale) prices. This
program has a number of criteria that must be met in order for the PIIC to qualify, including:
The renewable generation must be located in DEA’s service territory.
The renewable energy must be delivered into the DEA distribution system and must stay on
the distribution system. Under this condition, renewable energy is not allowed to back-feed
(flow backwards) onto GRE’s transmission system.
Renewable generation is constrained by the amount of electrical load on the distribution line.
The less electrical load, the smaller the renewable system must be.
Because the rate that DEA will pay for power is higher under this option than under an avoided cost
option, this program is worth considering for a larger solar installation.
4.5.4
Wholesale Generation
Wholesale generation involves the direct sale of renewable energy generation to GRE or any other
market participant. Under this model, any generation owned and operated by the PIIC that is producing
in excess of the Dakota Electric Substation demand would export to the GRE transmission system.
GRE would purchase energy directly from the PIIC. This would require direct connection onto GRE’s
transmission system, triggering Midcontinent Independent System Operator (MISO) engineering
studies. GRE would purchase energy at their annually adjusted avoided cost rates (which typically
hover around $0.03/kWh) and would likely require system upgrades for interconnection. This model
is likely to be financially infeasible due to the low purchase price of energy.
4.5.5
Technical Considerations
There are a number of technical requirements to consider when interconnecting new generation onto
the grid. Electrical system impact studies are used to quantify the effects of new generation. DEA and
GRE have both provided preliminary technical feedback on costs and technical requirements for new
solar. These findings should be considered preliminary, and more investigation is needed. However,
they do provide a foundational overview of what can be expected when proceeding with the design
phase. The findings are described below.
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4.5.5.1
Great River Energy
At the request of the Net Zero Team and DEA, Great River Energy performed a preliminary Reliability
Study Report for new interconnection near the Ravenna Substation. GRE modeled solar arrays ranging
in size from 3MW to 50MW at full output connected on the distribution side of the Ravenna Substation.
They found that 3MW of distributed generation would cause overload violations on several of the
transmission lines and transformers. It was also found that if generation is higher than the minimum
load of the substation (637kW), a 161kV breaker addition will be needed at Spring Creek. The
minimum electrical load of the line throughout the calendar year is 637kW. Any amount of generation
that crosses that minimum threshold could lead to back-feed, which triggers the breaker addition.
In addition to the new breaker, GRE stated that two transmission lines would also need to be upgraded.
These lines include the Red Wing to Bay City line and the Red Wing to Spring Creek line. The estimated
costs for all of these upgrades are shown in Figure 32.
Figure 32 – Distributed Generation Solar Program Summary
Additional conversations between the Net
Zero Team, DEA, and GRE indicate that the
DER size
Transmission Impact
PIIC may not be responsible for the
transmission line upgrades and that they
No additional
may only need to cover the $500,000
Min load
No Impact
cost
breaker replacement. These talks are
ongoing and should be considered
Breaker station at
preliminary at this time. Additional
$500,000
Spring Creek
information from DEA showed that
daytime minimum load on the PIIC territory
Min load - 50 Red Wing to Bay City
served by the Ravenna Substation is
$1,000,000
MW
line
approximately 1,200kW. Since daytime
minimum loading is more suitable for solar
Red Wing to Spring
analysis, GRE may allow up to 1,200kW of
$1,000,000
Creek line 2
solar export before requiring the
$500,000 breaker addition. Another
option could be to install a PV controller that curtails or disables PV generation during minimum loading
times in order to avoid back-feed to the transmission system. Such a controller would reduce PV export
when utility demand is low and allow for maximum export when utility demand is high. Again, mitigating
back-feed can be accomplished via pairing energy storage solutions to charge the energy storage
system for future electrical demand.
Estimated
Capital Cost
Ultimately, more collaboration between the PIIC, DEA, and GRE is needed. What seems clear, however,
is that any large solar interconnection(s) (>1,200kW) will trigger a breaker addition upgrade costing
approximately $500,000 and approximately 2-3 years to implement. This addition should be included
in the financial model when calculating profitability and payback.
4.5.5.2
Dakota Electric Association
DEA has provided significant and valuable feedback on the interconnection technical processes. DEA
conducted a preliminary engineering review in which they modeled solar generation impacts onto their
distribution system. They found that a PV interconnection at Prairie Island Boulevard and County Road
18 (Mato Circle Triangle) is limited to approximately 2.0 – 2.5MW. Above this limit, the generation
starts to cause power factor problems at the substation and intolerable voltage swings during cloud
cover events. It is their recommendation that any array built at this location be constrained to the
2.0 - 2.5MW limit. They also recommend developing and constructing the array on the south side of
the railroad tracks.
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49
DEA also provided technical requirements for physical interconnection. When interconnecting larger
PV directly to DEA’s distribution lines, the system requires an electrically operated circuit breaker, a
12.5kV-480V transformer, a primary metering compartment and RTU controller, a 12.5kV pad mount
switch, and primary cabling to the interconnection point. DEA can provide all of this equipment
(excluding the electrically operated circuit breaker) and installation scope for approximately
$350,000.
For smaller installations, such as the 40kW or smaller net metering option, DEA requires a disconnect
switch with a visible break and a meter socket, provided by the customer. Both devices are industry
standard for utility solar interconnections.
4.5.6
Solar Analysis
The previous sections outlined the resource availability and technical requirements for different types
of solar Net Zero Projects. This section examines specific Net Zero Project siting and the associated
pros and cons. On the Reservation, there are generally three possible installation categories:
residential, distributed generation (building focused), and ground-mount. Each installation category
was reviewed based on a combination of financial payback, engineering complexity, interconnection
feasibility, visibility, and stakeholder input. These results are presented below.
4.5.6.1
Residential
Residential solar is highly viable for the PIIC. To approach Net Zero Project development equitably, the
Team estimated that every home would receive rooftop solar and modeled 3kW systems for each of
the 96 residences. Depending on the size of the residence, most residential rooftop solar installations
range in size between 3kW and 10kW; 3kW therefore represents a conservative approach to the total
amount of residential solar power available to the PIIC.
Since all residences have their own dedicated meters, each residential Net Zero Project would be
eligible for net metering. As discussed in the previous section, net metering is a more financially viable
method to interconnect solar and thus is more appealing than other utility programs. An additional
add-on to this approach could be to add additional electric generation and energy storage to the
system. Adding this would effectively create a residential microgrid. This approach will also be
evaluated in Phase 2. The preliminary Phase 1 residential results without a microgrid are summarized
in Figure 33.
Figure 33 – Residential Solar Program Summary
Net Zero Project
Description
Total System
Size
Estimated
Capital Costs
96 Three kW
Residential Solar Arrays
288 kW
$901,000
Emissions Reduction
(lbs CO2)
35,357
Simple
Payback
18 years
As shown in Figure 33, the installation of residential solar power for the PIIC carries a simple payback
of 18 years. This longer payback period is generally due to the low cost of electricity in Dakota Electric
territory, low economies of scale for small residential Net Zero Projects, and moderate solar resource.
However, one benefit of the residential program is that arrays are highly visible to the local community.
The arrays are located on individual houses and residents can physically see power being produced
during the day. The simple payback also does not factor in federal tax incentives such as the Solar
Investment Tax Credit (ITC). If the residences are eligible to utilize the ITC, payback will occur more
quickly.
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4.5.6.2
Distributed Generation
Commercial-scale rooftop solar is very common throughout the United States and is generally the most
cost-effective and least complex way for communities to harness renewable energy. Canopy solar Net
Zero Projects are also very popular, particularly in the Southwestern US where parking lot shading is
desirable. Canopy Net Zero Projects tend to be more expensive than rooftop Net Zero Projects due to
the additional structural steel and labor needed to erect standing structures. Prairie Island owns
multiple buildings and parking lots where distributed generation (DG) solar might be installed. As
discussed in the interconnection discussion, there are multiple programs available for smaller scale
interconnection. For Net Zero Projects up to 40kW in size, the Net Zero Project Net Zero Team modelled
the financial payback using the net metering option. For Net Zero Projects larger than 40kW, the Net
Zero Team modelled the financial payback using the self-generation option (including standby
charges). The distributed generation results are summarized in Figure 34.
Figure 34 – Distributed Generation Solar Program Summary
Net Zero Project
Location
Community Center
Rooftop
Public Safety Building
Rooftop
Heat Recovery Ground
Source Plant Rooftop
Tinta Wita Tipi
Rooftop
PIIC Administration
Rooftop
Mount Frontenac Golf
Rooftop
Dakota Station
Canopy
Elder Center
Rooftop
Total System
Size
Estimated
Capital Costs
Emissions Reduction
(lbs CO2)
Simple
Payback
31.5kW
$60,000
3,942
15 years
12kW
$23,000
1,309
17 years
175kW
$332,000
21,897
12 years
33.6kW
$64,000
4,204
19 years
43kW
$82,000
5,334
21 years
17.6kW
$33,000
2,126
17 years
40kW
$70,000
4,139
17 years
30kW
$57,000
3,000
23 years
The paybacks range from between 12 years to 23 years. Larger arrays experience beneficial
economies of scale and decrease the payback period. Similar to the residential analysis, solar payback
suffers from the low cost of electricity, and a moderate solar resource. The use of energy storage will
also need to be considered. Not captured here are potential economies of scale that may occur if all
solar projects were bundled into one larger one. This bundling may reduce upfront capital costs and
decrease the length of payback.
4.5.6.3
Ground-Mount
The PIIC is well positioned to take advantage of ground-mount arrays. They own hundreds of acres of
land, some of which is very well suited for larger ground-mount solar. Ground-mount solar can often
be the lowest cost configuration on a $/Watt basis. This is due to both the simplicity of installation and
the economy of scale benefits seen for larger Net Zero Projects.
For installations at the PIIC, the Net Zero Team modelled the installation of a 2MW Net Zero Project
with a direct interconnection onto DEA’s distribution, and a 2MW Net Zero Project allocated
proportionally to the casino’s electrical service meters. The proportional allocation model splits the
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
51
2MW array into four separate interconnections, two of which are 600kW and two of which are 400kW.
By breaking up the array into four individual interconnections, PIIC can take advantage of the selfgeneration interconnection option outlined in the interconnection discussion. The 2MW direct
interconnection was modelled utilizing the wholesale generation process (see Wholesale Generation).
There may be an opportunity to increase the payback of the 2MW direct interconnection depending
on DEA’s willingness to incorporate the array(s) into their 5% Options Program for Renewable
Generation. This option will require further collaboration with DEA.
The ground-mount results without energy storage are summarized in Figure 35.
Figure 35 – Ground-Mount Solar Program Summary
Net Zero Project Location
Total
System Size
Estimated
Capital Costs
Emissions Reduction
(lbs CO2)
Simple
Payback
2MW Mato Circle Triangle
Ground-Mount Array
2MW
$4,671,000
252,500
90 years
2MW
$4,671,000
252,500
21 years
2MW Frazier Street Lot
Ground-Mount Array
400 kW to Casino 1 & 2
600 kW to Casino 3 & 4
400 kW to Casino 6 & 7
600 kW to Hotel Casino 5
The paybacks for these large sites vary significantly depending on the method of interconnection
agreement. The 2MW with direct interconnections take 90 years for the Net Zero Project finances to
break even. This is due primarily to the very low price at which the Tribe can sell power back to GRE
under the wholesale generation interconnection arrangement. Alternatively, allocating blocks of the 2
MW array for behind-the-meter connections within the Casino-Hotel Resort electric accounts may yield
a simple payback of about 21 years. These connections assume an offset in the Tribe’s cost of
electricity; the self-generated power offsets utility power at a one-to-one rate after accounting for standby charges. This interconnection method also factors in standby charges, leading to a simple payback
period of 21 years. It is clear that unless DEA can incorporate the 2MW array into their 5% Renewable
Generation Program, the self-generation interconnection method is far more feasible than the
wholesale generation interconnection method.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
52
4.5.7
Potential Siting Map
The Net Zero Team worked in
conjunction with the PIIC personnel
from the Tribal Historic Preservation
Office (THPO) and Environmental
Office to evaluate sites. Preliminary
sites were chosen based on the
absence of known culturally sensitive
areas, existing disturbed ground, and
proximity to existing distribution
systems. Sites were then narrowed
down to the most likely to be
electrically feasible, and further
reviewed with the PIIC Tribal
leadership and community members.
The sites chosen for potential solar
development sites are in three
separate
locations
on
the
Reservation, as shown in Figure 36.
Figure 36 – Aerial View of the Three Potential Array Locations on the PIIC
The specific size and precise location for these generation sites will be determined during Phase 2;
however, 2MW for each array is used for these examples based on the likely capacity for the nearby
distribution system. Figure 37 is near the TIRC. This location provides several opportunities to connect
to either the distribution system running underground adjacent to TIRC, or directly to the existing DEA
substation nearby to the South.
Figure 37 – Location of a Potential 2MW Array Adjacent to TIRC
Figures 38 and 39 are twin sites located across from one another on County Road 18 and near the
PIIC residences of Mato Circle. Because of existing system capacity, it is likely only one of these sites
would be chosen; however, the size of the array might be scaled up to 3MW or more to meet existing
capacity. This will also be determined in Phase 2.
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
53
Figure 38 – One of Two Potential 2MW Arrays Near the Mato
Circle Residences
4.5.8
Figure 39 – The Second of Two Potential Arrays Near the
Mato Circle Residences
Transpired Solar Thermal
Buildings are typically heated and cooled with distributed air through air handling units. These units
typically rely on gas or electricity to heat the air during cooler seasons. The cost of heating as well as
the energy used can add up over a cold winter. Additionally, commercial buildings use a significant
amount of outdoor air, which further increases the energy and or electricity use as the cold winter air
needs to be heated.
Transpired Solar Thermal Collectors (TSTC) typical consist of a dark-colored, perforated façade
installed on the building’s south-facing wall. A fan in the ventilation system draws in air through the
wall to the air handling unit’s outdoor air intake. The dark panels of the wall absorb solar energy during
the day and heat the air as it passes through. The TSTC can pre-heat air by as much as 40°F. The
panels continue to collect energy at night as the heat lost through the exterior of the building is
recaptured.
The proposed solution involves installing a 1,250 sq ft TSTC on the south wall of the Buffalo Hotel
tower. The collector design coordinates with windows and HVAC equipment on the existing façade. The
system also includes rooftop ductwork, in-line fans and controls integrated into the BAS. The collector
supplies 5,000 cfm of pre-heated ventilation air to the hotel tower ventilation system. This equates to
574,000 kWhs of annual solar thermal energy generation. The system reduces ventilation air system
operational energy costs by 90% and prevents 286,000 lbs of annual CO2 emissions.
4.6
ELECTRIFICATION
Electrification of natural gas loads is an important consideration of the Net Zero Project given the
noted and successful decarbonization efforts of the Minnesota electric utility industry.
Consequently, measures for electrification potentially offer greater reductions of CO2 emissions than
Renewable Generation measures per dollar of capital invested. Although it may seem intuitive to
continue to use a natural gas system and/ or appliance until end of life, when carbon emissions
reduction is the primary goal, the sooner the electrification happens the faster emissions reductions
are realized.
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4.6.1
4.6.1.1
Casino-Hotel Resort
Laundry Washer/Extractor Washwater
The laundry facilities serving TIRC include five (5) commercial grade laundry washer/extractors. These
units are Milnor 160-lb units; capable of 300 G of extractor force. Together, these units sum to a total
facility washer/extractor capacity of 800 lbs. Domestic Hot Water (DHW) to serve the washer extractors
is generated via two (2) brazed plate heat exchangers. Building heating water at 160°F heats
circulating DHW from three (3) 200-gallon storage tanks. This system heats and stores DHW to 140°F
and serves both the laundry facilities as well as nearby hotel spaces.
DHW accounts for the majority of the energy and emissions associated with washing laundry. This
energy enters the washer/extractors as DHW and is drained at the conclusion of the wash
cycle, making this system an excellent candidate for the application of energy recovery equipment. In
this case, a Drain Water Heat Recovery (DWHR) heat exchanger would extract remaining heat from the
flow of wastewater and use it to pre-heat the fresh DHW. However, these heat exchangers must be
installed vertically with a drop in elevation to allow for the wastewater stream to form a thin film along
the piping walls within the heat exchanger to achieve adequate heat transfer rates. The modifications
to the facility’s sanitary piping infrastructure required to install this system would be extensive.
Although DWHR systems can be very effective in new construction or when existing conditions are
accommodating, the Team’s analysis determined that a DWHR system would be impractical and too
capital intensive for this application when compared to alternative solutions.
The Net Zero Team’s proposed solution re-purposes all of the existing laundry washing and water
heating equipment and installs new equipment to achieve significant CO2 emissions reduction. DHW
is first pre-heated by the existing brazed plate heat exchanger from 47°F or colder ground water
temperature by the new 120°F building heating water. DHW from the existing storage tank flows into
a new package tank-style Air Source Heat Pump Water Heater (ASHPWH). To safely store DHW, a
system must maintain a minimum temperature of 122°F to avoid Legionella growth. As the building
heating water is below this temperature, the ASHPWH is included to bring the DHW to a final storage
temperature of 140°F. The ASHPWH is powered by electricity and concentrates waste heat from the
laundry facilities room air at a greater than 400% efficiency. Finally, DHW mixing valves and plumbing
to the washer/extractors will be modified to utilize 75°F DHW from the existing storage tanks as “cold”
water to mix with 140°F DHW to minimize high temperature demand required to
achieve desired temperatures.
In addition, a significant amount of energy use can be avoided at a favorable cost by switching to cold
water enzyme washing detergent technology. These detergents maintain the same cleaning
performance at 100°F wash water temperature as traditional detergents do at 120°F wash water
temperature. This 20°F reduction represents a 27% reduction in required heating energy. Further
benefits may also manifest from decreases in water volume and linen replacement rates from high
temperature damage.
Although the switch to new detergent involves an increase in operational costs for the laundry facilities,
the reduction in DHW demand results in a net 14.6% decrease in operational material and energy
expenses. This measure has the potential of a net reduction in annual operating expense,
approximately $19,000, with an estimated capital cost of $47,000.
4.6.1.2
Laundry Dryers
The laundry facilities serving the TIRC include six (6) commercial grade tumble dryers. Five (5) of these
units are Huebsch 200-lb units; moving 2,150 cfm of air and consuming 425,000 btu/hr of natural
gas while in operation. The remaining single (1) unit is a Huebsch 170-lb unit; moving an identical
2,150 cfm of air while consuming 395,000 btu/hr of natural gas while in operation. In addition,
PRAIRIE ISLAND INDIAN COMMUNITY NET ZERO PROJECT
55
outside air supply to the tumble dryers is pre-heated during winter months by a RuppAir make-up air
unit consuming 513,000 btu/hr of natural gas. Together, after converting to the common measure
of therms, the laundry drying plant has a peak natural gas consumption capacity of
30.3 therms/hr while handling 1,170 lbs of laundry per hour.
The Net Zero Team developed an estimate for annual dryer service using standard design guidelines
for laundry facilities. The model load profile assumed 919 hotel rooms being served, with 20 lbs/day
of laundry per room at a 0.263 room occupancy rate. These inputs produced an estimated average
201 lbs/hr of laundry to be handled by the laundry facilities. Using local climate data, the modeled
laundry facilities consume 42,200 therms of natural gas, representing an annual fuel cost of $23,600
and annual emissions of 494,000 lbs CO2. In perspective, 3% of the annual natural gas consumption
for the Treasure Island Casino complex is accounted for by the laundry tumble dryers.
Drying laundry is a seemingly simple task but presents a complex and fascinating engineering
challenge if system emissions are to be reduced or eliminated. In developing an engineered solution to
meet this challenge, the Net Zero Team reviewed the fundamental physical principles guiding the
operation of a tumble dryer systems. Initially, the Net Zero Team noted that all tumble dryers do
consume electricity to power control electronics, exhaust fan(s) and rotating drums. Although new
equipment would make incremental improvements to energy consumption of these components, the
portion of total energy consumption this represents is negligible and the associated electrical waste
heat only aids in drying performance of the system. Therefore, the Net Zero Team has omitted the
electrical energy consumed by these accessory components from this discussion.
The vast majority of energy consumed, and emissions produced by a tumble dryer comes from the
task of heating a relatively large flow of air. This air is first pre-heated from outside ambient conditions
to approximately room temperature, before it is then heated to 175°F by the dryer and brought into
contact with tumbling laundry. In Minnesota, winter outside ambient air temperature conditions can
reach -10°F or lower. This is a relatively energy intense process that is further exacerbated by the fact
that 100% of the airflow and energy consumed by the tumble dryer system is exhausted and wasted
back to the outside environment. This compares to a typical HVAC air handling system taking in mixed
room and outside air at 55°F and heating it to 90°F to heat a building.
Reducing CO2 emissions from a natural gas fired tumble dryer can be achieved with heat pump
technology to actively remove moisture from the airstream, heat transfer components to maximize
overall system efficiency.
The proposed split Heat Pump Air Dryer (HPAD) system converts the TIRC’s laundry tumble dryers to a
closed system. A 12,900 cfm Air Drying Air Handling Unit (ADAHU) is installed outside adjacent to
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