This page last reviewed November 3, 2015

U.S. EPA's Rules to Regulate Power Plants



In June 2013, President Obama unveiled his Climate Action Plan (Plan).  The plan is a national blueprint to slow the effects of climate change, and focuses on both carbon dioxide (CO2) and short lived climate pollutants, such as methane, nitrous oxide (N2O) and hydrofluorocarbons.  The plan encompasses many sources of greenhouse gas emissions, including industrial and transportation sources.  

More information about the Climate Action Plan can be found here:

The Climate Action Plan directs the United States Environmental Protection Agency (U.S. EPA) to promulgate rules to address CO2 emissions from new and existing power plants, which nationally emitted over 2 billion metric tons of CO2 in 2012; the largest single source of greenhouse gas emissions in the country.

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New, Modified and Reconstructed Power Plants  

On September 20, 2013, U.S. EPA proposed a rule, under Section 111(b) of the Federal Clean Air Act, to limit CO2 emissions from future fossil-fueled power plants.  ARB worked closely with the state energy agencies to evaluate U.S. EPA's proposed power plant rules.  Together, we developed comments on U.S. EPA's proposal.  (See:  

On August 3, 2015, U.S. EPA released the final rule, under Section 111(b) of the Federal Clean Air Act, to limit COemissions from new, modified and reconstructed fossil-fueled power plants.  The final rule is codified in Subpart TTTT of Chapter 40, Part 60 of the Code of Federal Regulations. 

Subpart TTTT of Chapter 40, Part 60, of the Code of Federal Regulations (also known as the 111(b)) requires certain electrical generating units (EGUs) constructed after January 8, 2014 or that commenced reconstruction after June 18, 2014 to meet specific CO2 emission standards.  The regulation has several exemptions from the requirements (see regulation for more information).

The specific emission standards are broken out based on an electric generating unit (EGU) being either a new, modified or reconstructed steam generating unit or integrated gasification combined cycle; or a new or reconstructed combustion turbine.  Please see Table 1 and Table 2 of the regulation for the specific emissions requirements.  The regulation also includes specific monitoring, recordkeeping and reporting requirements.

ARB staff will be working with our energy partners and our local air pollution and air quality control districts to develop appropriate permit conditions that incorporate the requirements of Subpart TTTT for affected units.

The final new, modified and reconstructed power plant rule can be found here:

Existing Power Plants  

Also on August 3, 2015, U.S. EPA released the final emissions guidelines to regulate CO2 emissions from existing power plants under Section 111(d) of the Clean Air Act.  That regulatory package is also known as the Clean Power Plan (CPP).  U.S. EPA estimates that the proposed rule will reduce CO2 emissions from the power sector 32% by 2030 from 2005 emissions.  ARB worked closely with the state energy agencies to evaluate the CPP and provided comments to U.S. EPA.  (California’s comment letter to U.S. EPA can be found here:

U.S. EPA listened to California and the final rule includes many provisions that will allow California to meet the requirements of CPP while maintaining and extending the state’s programs established under AB 32, the Global Warming Solutions Act of 2006. The final rule is codified in Subpart UUUU of Chapter 40, Part 60 of the Code of Federal Regulations.  Subpart UUUU (also known as the 111(d) requirements) requires each state, including California, to establish standards of performance for carbon dioxide emissions from certain existing electric generating units (EGUs).

The California Air Resources Board (ARB) is developing California’s compliance plan for this federal rule and consulting as appropriate with other state regulators, including the California Energy Commission, California Public Utilities Commission, and California's air districts, among others.  Under Subpart UUUU, California is required to submit a plan by September 6, 2016 or provide an initial submission requesting an extension (up to September 6, 2018).  The plan must include measures to meet the federally mandated emissions goals for units subject to the regulation.  The regulation includes several goal options for states to meet, including meeting a state specific rate based goal, a state specific mass based goal, or a state specific mass based goal that includes new units. (See the specific goals in Tables 1, 2 and 3 of the regulation).  The compliance periods begin in 2022, with a final goal to be met in 2030 and beyond.  The regulation also includes an option for a state to trade credits and the ability to include a Clean Energy Incentive Program.  The final rule includes a variety of paths a state may take to meet the goal requirements.  Staff is currently assessing these options and will hold workshops to obtain stakeholder input.

The final rule for existing power plants can be found here:  

Proposed Federal Plan for the Clean Power Plan

On August 3, 2015 EPA also proposed a federal plan for existing fossil-fueled fired EGUs under the Clean Power Plan (See

The purpose of the proposed federal plan is to establish requirements directly applicable to a state’s affected EGUs in the case where a state or other jurisdiction does not submit an approvable plan.  These proposals also constitute proposed model trading rules that states can adopt or tailor for implementation of the final EGs.  The proposal also contains enhancements to the CAA section 111(d) framework regulations related to the process and timing for state plan submissions and EPA actions.

EPA will be holding workshops throughout the country.  Comments can be submitted for up to 90 days after it is published in the federal register.

The inadvertent error correction memo can be found here:

Environmental Justice

Environmental justice is a core priority for ARB.  As ARB develops compliance efforts for these federal rules, it will give careful consideration to the implications of its federal compliance programs for disadvantaged communities.  ARB welcomes comments and questions from members of those communities.

ARB’s ongoing Adaptive Management efforts, which include programs that track the effects of the Cap-and-Trade program is likely to play a role in its federal compliance efforts.  U.S. EPA has highlighted these programs as important environmental justice efforts in the preamble of the final Clean Power Plan.

More information about the Cap-and-Trade Adaptive Management can be found here:

Public Workshops

Upcoming Workshops:

Date and Time Title Location Materials
October 2, 2015

9:00am - 5:00pm

Public Workshop on Potential 2016 Amendments to the Cap-and-Trade Regulation and California Plan for 111(d) Compliance
Cal/EPA HQ Building
Byron Sher Auditorium
1001 I Street, 2nd Floor
Sacramento, CA 95814

List Serve Notice

White Paper

View Comments


Archived Workshops:

Date and Time Title Location Materials
September 9, 2014
Public Workshop to discuss U.S. EPA's Proposed Rules to Regulate Power Plants

On September 9, 2014: ARB in collaboration with the California Energy Commission (CEC), and California Public Utilities Commission (CPUC) held a public meeting to discuss U.S. EPA's proposed Clean Power Plan.  At the Workshop, staff presented an overview of U.S. EPA's proposed rule, including a brief discussion of how U.S. EPA applied the four building blocks to establish California's emission limits.  In addition, staff shared their analysis of the impacts of the proposed rule on existing energy and AB 32 programs and discussed our preliminary comments on elements of the proposed rule we plan to support and where we have identified concerns.

Cal/EPA HQ Building
Byron Sher Auditorium
1001 I Street, 2nd Floor
Sacramento, CA 95814


Discussion Paper 


Public Comments 

For information, please contact:
Chris Gallenstein
(916) 324-8017

Climate Change