Clean Energy Standards: Selected Issues for the 117th Congress

Clean Energy Standards: Selected Issues for

the 117th Congress

Updated November 2, 2021

Congressional Research Service

https://crsreports.congress.gov

R46691

SUMMARY

Clean Energy Standards: Selected Issues for the

117th Congress

For many years, policies to reduce greenhouse gas (GHG) emissions have been of interest to

Congress. Congressional and constituent interest continues in the 117th Congress. One option to

reduce GHG emissions from electricity generation is a clean energy standard.

R46691

November 2, 2021

Ashley J. Lawson

Analyst in Energy Policy

A clean energy standard (CES), sometimes called a clean electricity standard, is a policy that

requires a minimum share of electricity to be generated from eligible “clean” sources. No universal definition of clean energy

exists, and proposals differ in what technologies are included. Some proposals, usually referred to as a renewable portfolio

standard (RPS), include only certain renewable energy sources (e.g., solar), while other proposals also include nuclear power,

fossil fuels equipped with carbon capture and storage (CCS) technology, certain natural gas technologies, or other energy

sources. As of 2020, thirty states and the District of Columbia have implemented a CES, including 10 jurisdictions that will

ultimately require 100% of covered electricity sales to come from eligible clean energy sources. In addition, eight states have

nonbinding goals of carbon-free electricity, and many utilities have committed to reducing their GHG emissions to varying

degrees and over different time frames. State targets and utility goals cover 77% of total U.S. electricity sales, with 69% of

total sales covered by a carbon-free target or goal.

Members of Congress have demonstrated a long-standing interest in CES policies, with proposals for a national CES dating

at least to 1997. None has been enacted. Most recently, four bills introduced to date in the 117th Congress would establish a

national CES (sometimes in conjunction with other policies). The measures differ in eligible sources, final targets, and

implementation details. For example, one bill would require 70% of covered electricity sales to come from new renewable

energy sources by 2030. Another bill would establish CES targets consistent with 80% reductions in electricity GHG

emissions. The 116th Congress considered but did not enact seven similar CES bills.

The Biden Administration has expressed support for a 100% CES as part of its commitment to reduce U.S. GHG emissions

by 50%-52% from 2005 levels by 2030. A Clean Electricity Performance Program (CEPP) was proposed to help achieve this

goal. The proposed CEPP would aim to achieve the same goals as a CES but through a different policy structure (one

designed to meet requirements for passage through budget reconciliation). For context, renewable sources made up 21% of

U.S. electricity generation in 2020, nuclear power made up 20%, natural gas made up 40%, and coal (without CCS) made up

19%. In February 2021, the U.S. Energy Information Administration (EIA) projected the share of total U.S. electricity

generation coming from renewable sources in 2050 might vary from 33% to 57%, depending on factors such as future energy

prices and economic growth. The share from all nonemitting sources (i.e., renewables and nuclear) in 2050 varied from 44%

to 67% in the projections, and the share from nonemitting sources together with natural gas varied from 86% to 93%.

Concerns and criticisms raised against a CES include its potential to reduce electric reliability, increase electricity rates, and

negatively impact environmental justice efforts. To a certain extent, a CES policy can be designed to address these concerns,

and some bills have included provisions to do so. Efforts to address one impact could exacerbate others, though uncertainty

remains on potential impacts of any specific policy. For example, multiple studies have evaluated the cost of achieving a

100% CES policy, with estimates ranging from $106 billion to over $2 trillion in cumulative costs. Some studies have also

estimated monetary benefits of a 100% CES, finding $715 billion to $1.7 trillion in cumulative benefits. In all cases where

costs and benefits were both estimated, studies found that benefits outweighed costs.

The future makeup of the U.S. electricity system might affect congressional perceptions of the necessity or feasibility of a

CES. Estimating the future energy system makeup typically is challenging, especially over 15 years or more (i.e., the time

periods covered by recent CES proposals). Another complicating factor is the possibility that the 117th Congress could

change U.S. energy policy (not including consideration of a CES). For example, infrastructure legislation under consideration

aims to accelerate deployment of certain kinds of clean energy technologies. Additionally, noncongressional action, such as

executive actions or state policies, could affect the U.S. electricity system. The interactions among some or all of these

factors might be relevant, should Congress choose to debate a CES.

Congressional Research Service

Clean Energy Standards: Selected Issues for the 117th Congress

Contents

Introduction ................................................................................................................... 1

Bills Introduced in the 117th and 116th Congresses ................................................................ 2

Potential Considerations................................................................................................... 4

Putting a 100% Target in Context ...................................................................................... 8

Current Clean Energy Use........................................................................................... 8

State Targets and Utility Commitments ......................................................................... 9

Outlook for Clean Energy in the U.S. Electricity System ............................................... 10

Concluding Observations .......................................................................................... 12

Figures

Figure 1. 2020 U.S. Electricity Generation by Source Type.................................................... 9

Figure 2. Projected Share of Total U.S. Electricity Generation, by Source Type ...................... 11

Tables

Table 1. National Clean Energy Standard (CES) Legislative Proposals in the 117th and

116th Congresses........................................................................................................... 3

Table 2. Cost and Benefit Estimates for 100% Clean Energy Standards ................................... 6

Contacts

Author Information ....................................................................................................... 12

Congressional Research Service

Clean Energy Standards: Selected Issues for the 117th Congress

Introduction

Congress continues to study and discuss a range of policies to reduce U.S. greenhouse gas (GHG)

emissions, and the Biden Administration has made reducing GHG emissions a priority. Several

legislative and executive actions could achieve such a goal. One legislative option, targeting the

U.S. electricity system, is a clean energy standard.

A clean energy standard (CES), sometimes called a clean electricity standard, aims to increase the

share of U.S. electricity generated from qualified clean energy sources. No agreed-upon definition

of “clean energy” exists, so the exact set of energy sources supported by a CES proposal is one of

its defining characteristics. Members of Congress have introduced legislation to establish a

national clean energy standard in every Congress since at least the 105th (1997-1998).1

The Biden Administration has expressed support for a CES as a key policy to reduce U.S. GHG

emissions by 50%-52% from 2005 levels by 2030, the target President Biden announced pursuant

to the Paris Agreement. 2 For example, the American Jobs Plan includes a 100% CES, and the

Department of Energy’s FY2022 budget request included funding for “programmatic

infrastructure” for a CES. 3 An executive order issued January 27, 2021, also states the goal to

“achieve or facilitate a carbon pollution-free electricity sector no later than 2035.”4 A Clean

Electricity Performance Program (CEPP; also called a Clean Electricity Payment Program)—

which would aim to achieve similar outcomes as the Biden Administration’s proposed CES, albeit

through a different policy structure—was proposed as part of the FY2022 budget reconciliation

process. Details of the program were included in House Committee on Energy and Commerce

budget reconciliation legislative recommendations, debated in August 2021. The CEPP text was

not included, however, in updated budget reconciliation language released in October 2021 by the

House Rules Committee. 5

As of 2020, 30 states and the District of Columbia have a CES. 6 Of these, 12 are to require all

covered electricity sales to come from eligible clean energy sources: California, Colorado, the

1

Seven of these measures were passed in at least one chamber, in all cases as part of comprehensive energy or

environmental legislation. No CES provision was enacted into law. For more information, see CRS In Focus IF11316,

A Brief History of U.S. Electricity Portfolio Standard Proposals, by Ashley J. Lawson. Past proposals have used

alternative names such as renewable portfolio standard (RPS) or clean electricity standard. An RPS includes only

renewable sources while a clean energy (or electricity) standard typically also includes nonrenewable sources like

nuclear power. Most policy considerations apply equally to RPS or CES. For simplicity, this report generally uses the

term CES to refer to any policy that would require certain sources be used for electricity generation, reflecting the

predominant usage in the proposals in the 116 th and 117 th Congresses. For more information about CES, see CRS

Report R45913, Electricity Portfolio Standards: Background, Design Elements, and Policy Considerations, by Ashley

J. Lawson.

White House, “ Fact Sheet: President Biden Sets 2030 Greenhouse Gas Pollution Reduction T arget Aimed at Cre ating

Good-Paying Union Jobs and Securing U.S. Leadership on Clean Energy T echnologies,” April 22, 2021. For

discussion of the Paris Agreement, see CRS In Focus IF11746, United States Rejoins the Paris Agreement on Climate

Change: Options for Congress, by Jane A. Leggett .

2

T he American Jobs Plan includes an Energy Efficiency and Clean Electricity Standard aimed at “100 percent carbon pollution free power by 2035.” White House, “ Fact Sheet: T he American Jobs Plan,” March 31, 2021; and U.S.

Department of Energy, “ Budget in Brief,” June 2021, p. 1.

4 Executive Order 14008, “Tackling the Climate Crisis at Home and Abroad,” 86 Federal Register 7619, February 1,

2021. Campaign quote comes from https://joebiden.com/clean-energy/#, accessed January 15, 2020.

3

5 For further discussion, see CRS Report R46934, The Clean Electricity Performance Program (CEPP): In Brief, by

Ashley J. Lawson.

6 Some of these states have an RPS in place, setting goals for renewable energy use only. T hree U.S. territories also

have an RPS. Eight additional states and one additional territory have voluntary renewable portf olio goals in place.

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Clean Energy Standards: Selected Issues for the 117th Congress

District of Columbia, Hawaii, Illinois, Massachusetts, New Mexico, New York, North Carolina,

Oregon, Virginia, and Washington. 7 Additionally, at least eight states have nonbinding goals of

100% covered electricity sales from eligible clean energy sources: Connecticut, Louisiana,

Maine, Michigan, Nevada, New Jersey, Rhode Island, and Wisconsin. 8

Experts disagree about the extent to which achieving a 100% CES presents cost or feasibility

challenges. Assessing the cost and feasibility of a 100% CES is beyond the scope of this report.

This report provides some analysis and discussion to inform potential CES policy debate in the

117th Congress, including a summary of CES proposals to date in the 117th and 116th Congresses.

Bills Introduced in the 117th and 116th Congresses

CRS identified four bills introduced in the 117th Congress to date and seven bills introduced in the

116th Congress that would establish a national clean energy standard. 9 Table 1 summarizes the

CES proposals identified in these 11 bills, focusing on two key policy features: the final target

and eligible sources. The final target is typically expressed as the maximum required share of

covered electricity sales to come from eligible sources and the year by which that share is to be

met. Final targets for many state CES policies and past legislative proposals apply uniformly

across all utilities (i.e., all utilities have to meet the same percentage in the same year); however,

several bills included in Table 1 set targets for each utility individually. This distinction is noted

in the table. Eligible sources refer to the energy sources that may be used for compliance with the

CES. Bills defined eligible sources by either source type (e.g., renewable energy, nuclear power)

or carbon intensity (i.e., the volume of GHG released per unit of electricity generated).

N.C. Clean Energy T echnology Center Database of State Incentives for Renewables & Efficiency (DSIRE), Renewable

Portfolio Standards and Clean Energy Standards, September 2020.

7

T he District of Columbia, Hawaii, Massachusetts, and Virginia each require 100% of covered electricity sales to come

from renewable energy sources. T he dates for achieving those targets vary. In some jurisdictions (e.g., Colorado, North

Carolina), only investor-owned utilities meeting size requirements are covered. In 2020, Arizona regulators approved a

100% CES, but the policy is not yet finalized. Additionally, Puerto Rico has a 100% RPS.

8 Generally, a nonbinding goal has no penalty for failing to meet it, while a binding goal or a requirement does. Some

nonbinding goals were enacted through legislation, while others were adopted by executive order. T he group Clean

Energy States Alliance (CESA) tracks state goals and provides a table with more information about state clean energy

targets. CESA, “States with 100% Clean Energy Goals,” at https://www.cesa.org/projects/100-clean-energycollaborative/guide/table-of-100-clean-energy-states/. As of the time of this writing, CESA identifies the eight states

listed in the body of this report. Governors in other states, such as North Dakota and Wyoming, have made public

statements supporting carbon reductions in their states, though not necessarily carbon-free electricity generation. See

Adam Willis, “Gov. Doug Burgum Calls for North Dakota to be Carbon Neutral by 2030,” Grand Forks Herald, May

12, 2021; and Mead Gruver, “Governor of T op Coal-Mining State Sets Carbon-Negative Goal,” AP, March 2, 2021.

9 Bills were identified by searching Congress.gov using the phrases “clean energy standard,” “ clean electricity

standard,” “ clean energy,” “ renewable electricity,” “ renewable energy,” and “ renewable portfolio standard” in full bill

text or bill summaries. Search results were refined by including only the Subject -Policy Area terms “Energy” and

“Environmental Protection.” Some bills contained policy provisions other than CES, but those other policies are not

summarized in this report.

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Clean Energy Standards: Selected Issues for the 117th Congress

Table 1. National Clean Energy Standard (CES) Legislative Proposals in the 117th

and 116th Congresses

Short Title

Bill

Number(s)

Final Target

Eligible

Sources

Selected Distinguishing

Feature(s)

117th Congress

CLEAN Future Act

H.R. 1512

100% by 2035

Renewables,

nuclear, CCS,

natural gas

Targets set individually for every

electric utility. Certain sources

must account for GHG emissions

during production and transport

of fuel. Direct air capture eligible

for credits. Eligible sources must

meet defined labor standards.

American

Renewable Energy

Act of 2021

H.R. 3959

70% by 2030

Renewables,

excluding

existing

hydropower

Carve outs for distributed

generation and generation

located in defined impacted

communities.

Clean Energy Future

Through Innovation

Act of 2021

H.R. 4153

80% reductions in

power sector

emissions by 2050

Any source

with annual

carbon

intensity less

than 0.82

metric tons

carbon

dioxide per

megawatthour

The CES comes into effect 10

years after enactment, or earlier

if defined market penetration

criteria are met for certain

technologies (e.g., coal-fired

power plants with CCS).

Clean Energy

Innovation and

Deployment Act of

2021

H.R. 4309

100% by 2050

Renewables,

nuclear, CCS,

natural gas

Targets set individually for every

electric utility. Emissions

reductions outside the power

sector (e.g., electrified space

heating, electric vehicle charging,

direct air capture) covered by

the CES.

Climate Solutions

Act of 2019

H.R. 330

100% by 2035

Renewables

Additional policy details not set

in legislation; instead, to be

determined by DOE regulations.

Clean Energy

Standard Act of

2019

S. 1359 / H.R.

2597

100% by 2050, or

potentially later for

some utilities

Renewables,

nuclear, CCS,

natural gas

Targets set individually for every

electric utility up to 90% before

2040, then increasing 1

percentage point each year after

utility reaches 90%.

Renewable

Electricity Standard

Act

S. 1974

1.5 percentage

points greater than

2019 levels in 2020;

increasing by 2

percentage points

annually for 20212029 and by 2.5

percentage points

annually for 20302035

Renewables

Targets set individually for every

electric utility.

116th Congress

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Clean Energy Standards: Selected Issues for the 117th Congress

Short Title

Bill

Number(s)

Final Target

Eligible

Sources

Selected Distinguishing

Feature(s)

Clean Energy

Innovation and

Deployment Act of

2020

H.R. 7516

100% by 2050

Renewables,

nuclear, CCS,

natural gas

Targets set individually for every

electric utility. Emissions

reductions outside the power

sector (e.g., electrified space

heating, electric vehicle charging,

direct air capture) covered by

the CES.

American

Renewable Energy

and Efficiency Act

H.R. 9036

91% by 2039

Renewables

Program administered by the

Federal Energy Regulatory

Commission (as opposed to

DOE)

Clean Energy Future

Through Innovation

Act of 2020

H.R. 9054

80% reductions in

power sector

emissions by 2050

Any source

with annual

carbon

intensity less

than 0.825

metric tons

carbon

dioxide per

megawatthour

CES comes into effect 10 years

after enactment, or earlier if

defined market penetration

criteria are met for certain

technologies (e.g., coal-fired

power plants with CCS).

Source: Prepared by CRS.

Notes: DOE = U.S. Department of Energy; CCS = fossil fuel-fired power plants equipped with carbon capture

and sequestration. Bills for each Congress are listed in chronological order by date of introduction. Final target is

the maximum share of eligible clean energy sources to be used for electricity generation required by the CES,

and the year by which that share is to be met. Carbon intensity refers to the volume of greenhouse gases

released per unit of electricity generation. Bills may have additional eligibility requirements for some sources

beyond those listed here (e.g., limitations on biomass sources, minimum carbon intensity requirements for

natural gas, consideration of upstream methane emissions for fossil fuels). Some bills contain additional policy

provisions.

Other legislation introduced in the 117th and 116th Congresses would address energy sources for

electricity generation directly (e.g., fossil fuel bans, net-zero emissions target) or indirectly (e.g.,

tax incentives for certain sources), but these measures are not discussed in this report. This report

also does not discuss carbon pricing proposals, although they, too, could potentially affect the

share of electricity coming from different sources. 10

Potential Considerations

A number of stakeholders—including the Biden Administration, some Members of Congress,

some climate change advocates, and some utilities—have voiced support for enacting a CES in

the 117th Congress, though with some disagreement over policy details. 11 Among both policy

10

In carbon pricing proposals, policymakers attach a price to GHG emissions or the inputs that create them. A price on

emissions or emissions inputs—namely fossil fuels—would increase the relative price of the more carbon -intensive

energy sources. T his result is expected to spur innovation in less carbon-intensive technologies and stimulate other

behavior that may decrease emissions. A summary of carbon pricing bills is provided in CRS Report R45472, MarketBased Greenhouse Gas Emission Reduction Legislation: 108th Through 117th Congresses, by Jonathan L. Ramseur.

11 See example statements in Ben Geman, “Exclusive: T he Big Push for a Clean Power Mandate,” Axios, April 26,

2021; Miranda Willson, “Clean Electricity Standard: A Boost fo r Coal?,” E&E News, May 18, 2021; and Zack Budryk,

“More T han 75 Companies Ask Congress to Pass Clean Electricity Standard,” The Hill, July 7, 2021.

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Clean Energy Standards: Selected Issues for the 117th Congress

supporters and opponents, several concerns and criticisms have been raised against a national

CES. To a certain extent, a CES can be designed to address these concerns. In some cases, efforts

to address any one concern could exacerbate others.

One consideration concerns nuclear power and carbon capture. Electricity generation using these

technologies generally receives policy support under most CES proposals, often at a level

comparable to electricity generation from renewable energy sources. Some environmental justice

advocates and others oppose policy support for these technologies for various reasons.12 For

example, the White House Environmental Justice Advisory Council included nuclear and CCS in

its list of “projects that will not benefit a community.”13 A CES is widely viewed as being

supportive of nuclear power and carbon capture projects, in contrast with a renewable portfolio

standard (RPS) that supports renewable energy only. Some CES proposals attempt to address

environmental justice concerns, either by excluding nuclear and carbon capture or through other

provisions. For example, the American Renewable Energy Act of 2021 (H.R. 3959) would

establish an RPS that also includes a carve out aimed at incentivizing the development of

renewable energy projects in defined “environmental justice communities,” among others.

A second consideration is electricity affordability, a topic of long-standing interest to Congress

and one receiving particular attention during the COVID-19 pandemic. 14 Many studies estimate a

CES would increase national average electricity prices compared with what they would be

without one. Table 2 summarizes cost estimates from studies of 100% clean energy standards or

clean energy standards with comparable goals. 15 Some studies attempted to model specific policy

details from bills listed in Table 1, while others modelled 100% CES policies in general. Given

the uncertainty in projecting power sector conditions in the future (even over the relatively short

period of 10-15 years), none of these studies individually is likely to correctly project future

costs. However, the range of cost estimates in these studies is likely a good indicator of the range

of outcomes should a 100% CES policy be enacted, assuming policy details are generally similar

to those assumed in these studies. 16

12 See discussion and points of view summarized in, for example, Letter from Center for Biological Diversity et al. to

Sen. Chuck Schumer, Majority Leader, Rep. Nancy Pelosi, Speaker of the House, Sen. Joe Manchin, Chairman of the

Energy & Natural Resources Committee, and Rep. Frank Pallone, Chairman of the Energy & Commerce Committee,

May 12, 2021, at https://www.biologicaldiversity.org/programs/energy-justice/pdfs/2021-5-12_600-Group-Letter-forRES.pdf; U.S. Congress, House Committee on Energy and Commerce, Subcommittee on Environment and Climate

Change, The CLEAN Future Act and Environmental Justice: Protecting Frontline Communities, 117 th Cong., 1 st sess.,

April 15, 2021; and Anthony Adragna, “Democrats’ Next Big Fight: What Exactly Is Clean Energy?,” Politico, April

30, 2021.

13

White House Environmental Justice Advisory Council, Final Recommendations: Justice40, Climate and Economic

Justice Screening Tool and Executive Order 12898 Revisions, May 21, 2021, p. 59.

14

For example, many states implemented moratoria on service disconnections for nonpayment (i.e., shut -offs) in 2020

so that individuals could maintain access to electricity during stay -at-home orders. For further discussion, see CRS

Report R46401, COVID-19 Electric Utility Disconnections, by Richard J. Campbell and Ashley J. Lawson.

15 One group modelled an 80% clean by 2030 standard on the grounds that “t he Biden administration goal of 100

percent clean power by 2035 implies an interim goal of at least 80 percent by 2030.” Mike O’Boyle et al., A National

Clean Electricity Standard to Benefit All Americans, Energy Innovation, April 2021, p. 1. Some modelling groups

identified in Table 2 are collaborations among researchers from several organizations (e.g., the Clean Energy Futures

Project). Media and other reports of these studies may refer to them by different names, such as o ne member of the

group. Table 2 excludes studies that looked at decarbonization in general but not a CES specifically.

16

T he range of cost estimates in Table 2 probably do not reflect likely outcomes of the proposed CEPP, because that

policy is expected to shift costs from electricity customers to federal taxpayers, relative to a CES. Lindsey Walter,

Don’t Call It a Standard: What’s Unique About the Clean Electricity Payment Program (CEPP) , T hird Way, August

12, 2021.

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Clean Energy Standards: Selected Issues for the 117th Congress

Table 2. Cost and Benefit Estimates for 100% Clean Energy Standards

Policy Costs,

Relative to

Business-as-Usual

Policy Benefits,

Relative to

Business-as-Usual

Modelling Group

Policy Details

Resources for the

Future

77% clean in 2035

$106 billion

increase in

electricity costs;

$29 billion

increased federal

expenditure for

increased use of

energy tax credits

$470 billion in

reduced climate

change impacts;

$226 billion in

reduced premature

deaths (due to

lower levels of copollutants); $19

billion in increased

utility profits

Reported costs and

benefits are the net

present value of

cumulative 20202035 costs and

benefits.

Electric Power

Research Institute

100% clean by 2050

50% increase in

national average

annual wholesale

electricity price in

2050

not calculated

Study also reports

changes in

wholesale electricity

prices by region.

Alternative

scenarios model a

100% by 2035 CES

and variations on

policy design

elements (e.g., point

of regulation,

alternative

compliance

payment).

FTI Consulting

80% clean by 2030

and 100% clean by

2035

0.25% reduction in

2031-2035 average

national GDP

not calculated

Costs reported as

net GDP impacts,

including, for

example, economic

benefits associated

with increased

investment in

electricity

infrastructure. Study

also reports impacts

in earlier years and

by region.

National Bureau of

Economic Research

100% clean by 2035

$1-$4/MWh

increase in national

average wholesale

electricity price in

2035

not calculated

Study also reports

electricity price

changes by state.

Goldman School of

Public Policy,

GridLab, Energy

Innovation

80% clean by 2030

6% increase in

national average

wholesale electricity

costs in 2030

$1.7 trillion in

reduced climate

change and health

impacts (from

power sector

reductions only)

Policy scenario also

includes increased

electrification of

end uses (e.g.,

transportation).

Study also reports

cost estimates with

health and

environmental

externalities

included.

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Notes

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Clean Energy Standards: Selected Issues for the 117th Congress

Modelling Group

Policy Details

Policy Costs,

Relative to

Business-as-Usual

Policy Benefits,

Relative to

Business-as-Usual

Notes

American Action

Forum

100% clean by 2035

$1.8-$2.13 trillion

cumulatively, 20212035

not calculated

Costs are for

generation assets

only. Study also

reports changes in

customer utility

bills.

Clean Energy

Futures Project

100% clean by 2040

$342 billion

$637 billion in

reduced climate

change impacts;

$1.13 trillion in

health impacts

Costs and benefits

are reported as net

present value of

cumulative benefits

2020-2050. Study

also reports air

quality

improvements by

county.

Natural Resources

Defense Council

and Environmental

Defense Fund

80% clean by 2030

or 100% clean by

2035 (study does

not report results

for individual

scenarios)

$17-$22 billion

annually, on

average, through

2030

$97-$184 billion in

2030

Net present value

of costs and

benefits are

reported as the

range over multiple

scenarios. Some

scenarios include

additional policies,

such as tax credit

extensions. At least

one scenario

models a Clean

Electricity Payment

Program.

Sources: Resources for the Future, “Projected Effects of the Clean Energy Standard Act of 2019,” May 2019, at

https://www.rff.org/publications/issue-briefs/projected-effects-clean-energy-standard-act-2019/; Electric Power

Research Institute, “Analyzing Federal 100% Clean Energy Standards,” February 2021, at https://www.epri.com/

research/products/000000003002020121; FTI Consulting, “Power Market and Economic Impacts of a U.S. Clean

Energy Standard,” March 2021, at https://www.remi.com/event/scott-nystrom-power-ma rket s-and-economicimpacts-of-a-u-s-clean-energy-standard-ces/; National Bureau of Economic Research, “Robust Decarbonization of

the U.S. Power Sector: Policy Options,” April 2021, at https://www.nber.org/papers/w28677; Goldman School of

Public Policy, GridLab, and Energy Innovation, “2030 Report: Powering America’s Clean Economy,” April 2021,

at https://energyinnovation.org/wp-content/uploads/2021/04/2030-Report.pdf; American Action Forum, “The

Cost of Clean Generation,” June 2021, at https://www.americanactionforum.org/research/the-cost-of-cleangeneration/; Clean Energy Futures, “An 80x30 Clean Electricity Standard: Carbon, Costs, and Health Benefits,”

July 2021, at https://cleanenergyfutures.syr.edu/; Natural Resources Defense Council and Environmental Defense

Fund, “80% Clean Power by 2030: Achievable With Massive Benefits,” August 2021, at https://www.nrdc.org/

experts/arjun-krishnaswami/80-clean-power-2030-achievable-massive-benefits.

Notes: Some studies modelled policies other than 100% CES, but the modellers identified those policies as

being comparable in stringency. Differences among studies include assumptions about business-as-usual

conditions; the makeup of clean energy sources used to satisfy policy requirements; cost metrics; policy details;

and the levels of greenhouse gas emission reductions. As a result, individual studies cannot necessarily be

compared with each other. For simplicity, this table shows total national electricity system costs, or the nearest

comparable cost estimate provided. Some studies estimated costs for different geographic scope (e.g., by state)

or for a different metric (e.g., customer bills). The Notes column lists other reported cost estimates as a

research aid.

A third consideration is electricity reliability, another issue of long-standing interest to Congress.

Blackouts following extreme weather events in 2020 and 2021 reignited debate about whether

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changing energy sources for electricity generation (i.e., increased use of wind and solar energy,

decreased use of coal) pose threats to reliability. 17 For example, a House committee held a hearing

on the days-long power outages that affected much of Texas in February 2021, and issues of

electric reliability and changing energy sources were discussed.18 Some stakeholders see inclusion

of natural gas in a CES as a way to ensure reliability. 19 Another option is to exclude from

compliance calculations any emissions from power plants that are required for reliability

purposes. The CLEAN Future Act (H.R. 1512, as introduced), for example, includes both these

provisions. 20

Putting a 100% Target in Context

Current Clean Energy Use

As summarized above, most recent CES proposals would require nearly all electricity to come

from eligible clean energy sources in the 2035-2050 timeframe. The distinction between “all” and

“nearly all” arises from the policy details provided in some of the proposals. A 100% target does

not necessarily require 100% of electricity to come from eligible clean sources. For example, a

CES might exempt electricity sales from small utilities or allow alternative compliance

payments. 21 The actual amount of clean energy used would be affected by utility compliance

choices, future technology costs, and other factors.

How much clean energy was used in the U.S. electricity sector in 2020? The answer depends

upon what sources are considered to be clean, as shown in Figure 1 and discussed in the

following paragraphs. In 2020, renewable energy fueled 21% of U.S. electricity, while renewable

energy plus nuclear power fueled 40%. 22 These sources together with natural gas fueled 80% of

U.S. electricity in 2020.

17

Wind and solar energy have different operational characteristics than conventional ener gy sources (e.g., coal, natural

gas, nuclear power), and they are variable in nature. Because the electricity grid was primarily designed to

accommodate conventional sources that can be called upon as needed (barring extreme events or regular maintenance

requirements), some system design and operational changes may be required to integrate large amounts of wind and

solar energy. For a discussion of these issues and potential solutions, see CRS In Focus IF11257, Variable Renewable

Energy: An Introduction, by Ashley J. Lawson.

18

U.S. Congress, House Committee on Energy and Commerce, Subcommittee on Oversight and Investigations, Power

Struggle: Examining the 2021 Texas Grid Failure, 117 th Cong., 1 st sess., March 24, 2021. Most experts do not identify

changing energy sources as a main contributor to the T exas outages, though some observers see the two issues as being

connected. For further discussion, see CRS Insight IN11608, Power Outages in Texas, by Richard J. Campbell.

19 See, for example, Molly Christian and Zack Hale, “Gas T reatment, Infrastructure T ensions Hamper Clean Electricity

Standard Efforts,” S&P Global Market Intelligence, June 10, 2021.

20 T he CLEAN Future Act would set an emissions intensity threshold for eligibility, including greenhouse gas (GHG)

emissions associated with fuel production and transport. Some natural gas-fired generators meet the eligibility

threshold when considering onsite emissions. It is unclear how many such generators would be eligible after accounting

for upstream emissions because the determination would be made pursuant to a to -be-determined U.S. Environmental

Protection Agency standard. See the CLEAN Future Act, §204(d).

21

T he point of regulation can also affect the extent to which a 100% target requires 100% of electricity to come from

eligible sources. Regulating load serving entities (typically, distribution utilities), as is frequently the case, can leave

“headroom” under the policy due to losses associated with electricity transmission and distribution. See discussion in

Electric Power Research Institute, “Analyzing Federal 100% Clean Energy Standards,” February 2021, available at

https://www.epri.com/research/products/000000003002020121.

22 U.S. Energy Information Administration (EIA), Monthly Energy Review, T able 7.2a and T able 10.6, July 2021.

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Figure 1. 2020 U.S. Electricity Generation by Source Type

Source: U.S. Energy Information Administration, Monthly Energy Review, “Table 7.2a. Electricity Net Generation:

Total (All Sectors)” and “Table 10.6. Solar Electricity Net Generation.”

Notes: Other includes petroleum and gases derived from fossil fuels. Details of energy source classification are

provided in this report and in the EIA source.

Figure 1 uses the following classifications. Renewable energy means all renewable energy

sources, including small-scale and distributed sources (e.g., rooftop solar), all hydropower, and all

biomass. Some introduced CES bills would limit the eligibility of hydropower and biomass, for

example by specifying types of eligible biomass feedstocks, but those limitations are not

considered here. Natural gas means any power plant using primarily natural gas, regardless of

technology type or carbon intensity. Some bills would allow natural gas plants to be eligible if

they met certain carbon intensity thresholds, but those limitations are not considered here. Should

Congress debate a national CES, it could set eligibility criteria based on energy source, carbon

intensity, or other characteristics.

State Targets and Utility Commitments

As noted above, eleven states plus the District of Columbia have enacted legislation to achieve

carbon-free electricity generation, and at least eight additional states have goals or executive

orders targeting carbon-free electricity generation. Beyond these state requirements, some electric

companies have made voluntary commitments to reduce GHG emissions from their electricity

generation. 23

23 T hese utility decarbonization goals vary in st ringency, scope, and final target date. T he most stringent

decarbonization goal is for 100% carbon-free electricity, also referred to as carbon neutral, net zero, or 100% clean.

Different terms for decarbonization are sometimes used interchangeably, though they can imply different

implementation options. For example, 100% carbon -free generally means all generation sources will be carbon-free,

while carbon neutral and net zero potentially leave open the possibility of offsetting some emissions with reduction s

outside the utility’s generation supply (e.g., retirement of renewable energy credits [RECs] from other states). Many

decarbonization target dates are between 2040 and 2050, outside the typical planning horizon for utilities. As a result,

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Clean Energy Standards: Selected Issues for the 117th Congress

Combined, these state targets and utility commitments cover 77% of U.S. electricity sales. 24 The

most stringent of these commitments—the carbon-free state targets and the utility commitments

of at least an 80% reduction in GHG emissions—cover 69% of U.S. electricity sales. 25

Outlook for Clean Energy in the U.S. Electricity System

The possible future makeup of the U.S. electricity system might affect (among other things)

congressional perceptions related to the necessity or feasibility of a CES. Estimating the future

energy system makeup typically is challenging, especially over multi-decadal periods. The

COVID-19 pandemic and other factors make such outlooks especially challenging.

One prominent estimate of future changes in the U.S. energy system is made each year by the

U.S. Energy Information Administration (EIA) in its Annual Energy Outlook (AEO). 26 The AEO

accounts for most federal and state energy policies (e.g., state CES policies) in place at the time

of its preparation. In February 2021, EIA released its first long-term projections accounting for

the pandemic. In EIA’s assessment, the pandemic’s impacts on the electricity sector will be

mostly felt in the next few years. After that, long-term sectoral trends return to dominance: “EIA

does not project long-term structural changes in electricity demand resulting from the pandemic,

and the AEO2021 Reference case projects that demand largely returns to 2019 levels by 2025.”27

In EIA’s 2021 projections, the share of total U.S. electricity generation coming from renewable

sources in 2050 varies from 33% to 57%, depending on factors such as future energy prices and

economic growth. The share from nonemitting sources (i.e., renewables and nuclear) in 2050

varied from 44% to 67% in the projections, and the share from nonemitting sources together with

natural gas varied from 86% to 93%. 28 Figure 2 compares EIA’s 2021 projections for the share of

many decarbonization targets—regardless of what they are called—do not have associated implementation plans.

Because of this uncertainty, it is difficult to assess meaningful differences among terms.

24 T otal electricity sales reported by the EIA. T he most recent annual data available are for 2019. CRS estimated the

share of total U.S. electricity sales covered by a utility commitment by compiling lists of companies with a

commitment from three sources: Smart Electric Power Alliance (SEPA), “Utility Carbon Reduction T racke r,” accessed

August 23, 2021, at https://sepapower.org/utility-transformation-challenge/utility-carbon-reduction-tracker/; Clean Air

T ask Force (CAT F), “State and Utility Decarbonization Commitments,” October 1, 2020; and Jeffrey Ryser, “ Utility

Emissions, Renewables Goals Accelerate, But Coal Retirements May Be T oo Slow,” S&P Global, February 25, 2021.

In some cases, the names of companies provided by SEPA, CAT F, or S&P Global do not match the utility names in the

EIA dataset. In these cases, CRS identified corresponding utilities (an exact name match was required to analyze the

EIA data) using utility websites and other public documents. Some identified utilities are also covered by a state target.

Sales from these utilities were counted once in the final estimate.

25

For this analysis, CRS assessed utility target stringency based on its characterization by SEPA, CAT F, and S&P

Global. CRS did not independently verify utility targets. Most identified utility targets are based on an absolute (i.e.,

mass-based) reduction in GHG emissions. For example, a utility might target a 90% reduction in carbon dioxide

emissions from 2005 levels by 2050. Some targets are based on relative (i.e., intensity-based) reduction in GHG

emissions. In theory, intensity-based reduction targets can be achieved without a reduction in absolute emissions.

Estimating future GHG emissions is beyond the scope of this analysis, so n o attempt was made to “convert” intensitybased targets into absolute targets. For example, a utility might target a 70% reduction in GHG intensity from 2005

levels by 2040. For purposes of estimating the share of electricity sales covered by commitments, that target is treated

the same as a 70% mass-based reduction target.

26 For an overview of the Annual Energy Outlook, see CRS In Focus IF11691, The Annual Energy Outlook (AEO): A

Brief Overview, by Ashley J. Lawson and Kelsi Bracmort .

27 EIA, Annual Energy Outlook 2021 Narrative, February 2021, p. 12, https://www.eia.gov/outlooks/aeo/pdf/

AEO_Narrative_2021.pdf.

28 CRS calculations based on data from EIA, Annual Energy Outlook 2021, February 3, 2021. EIA’s projections do not

include projections for CCS.

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total U.S. electricity generation coming from these different source types. The classifications in

Figure 2 match those in Figure 1, and are used to provide context.

Figure 2. Projected Share of Total U.S. Electricity Generation, by Source Type

Source: CRS calculations based on data from EIA, Annual Energy Outlook 2021, February 3, 2021.

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Notes: Details of energy source classification are provided in this report and in the EIA source. EIA side cases

include alternative assumptions about future energy supply and prices, technology costs, and economic growth.

Concluding Observations

Congressional debate on options to reduce GHG emissions is ongoing, including consideration of

a CES. Other issues being debated by the 117th Congress, such as infrastructure, could also affect

future GHG emissions from the power sector. For example, non-CES legislation could influence

power plant developers’ choice about energy sources by altering their relative prices in the market

(e.g., tax incentives to lower prices for certain sources or carbon pricing to increase prices for

certain sources). Legislation also could affect electricity demand by increasing use of electricity

in the economy (e.g., for transportation) or decreasing electricity demand by promoting efficiency

measures. Legislation not directly targeted at the electricity system also could affect the outlook

for clean energy in the U.S. electricity system. For example, legislation affecting overall

economic activity could affect future electricity demand, and infrastructure policy could influence

the private sector’s decisions about what energy sources to use for electricity generation. Also,

noncongressional actions (e.g., executive actions, state policies) affect the U.S. electricity system.

For example, the Federal Energy Regulatory Commission initiated a rulemaking process in July

2021 aimed at “improv[ing] transmission planning and cost allocation and generator

interconnection processes as the nation transitions to a cleaner energy future.”29

In short, numerous policies the 117th Congress might consider (and noncongressional actions as

well) could affect the future makeup of the U.S. electricity system. Should Congress also choose

to debate a CES, the interactions among some or all of these factors might be relevant.

Author Information

Ashley J. Lawson

Analyst in Energy Policy

Disclaimer

This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan

shared staff to congressional committees and Members of Congress. It operates solely at the behest of and

under the direction of Congress. Information in a CRS Report should not be relied upon for purposes other

than public understanding of information that has been provided by CRS to Members of Congress in

connection with CRS’s institutional role. CRS Reports, as a work of the United States Government, are not

subject to copyright protection in the United States. Any CRS Report may be reproduced and distributed in

its entirety without permission from CRS. However, as a CRS Report may include copyrighted images or

material from a third party, you may need to obtain the permission of the copyright holder if you wish to

copy or otherwise use copyrighted material.

29 Federal Energy Regulatory Commission, “ News Release: FERC Begins Reform Process to Build the T ransmission

System of the Future,” July 15, 2021.

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