Continuing Leadership: Progress in reducing emissions during Colorado’s 2025 legislative session  

During Colorado’s recent legislative session, CATF worked with the state and stakeholders to help pass several bills that help the state maintain its national leadership in reducing harmful air pollution and transitioning to a clean energy economy.  

Thanks to strong and consistent signals set by Governor Jared Polis and his administration over his nearly two terms as well as the Colorado General Assembly’s leadership, the state is maintaining its strong momentum in reducing emissions from some of its largest economic sectors. Examples of Colorado’s leadership include setting a technology-neutral clean electricity standard (CES) of 80% by 2030 in 2019, implementing first-in-the-nation requirements to reduce greenhouse gas (GHG) emissions from natural gas utilities in 2021, adopting rules and providing incentives for clean transportation in 2023, and more. 

CATF engaged on a wide array of important policy proposals in 2025, including the following bills that passed: 

• HB25-1040, which added nuclear energy as a clean energy resource, was a bipartisan bill led by one Democrat and one Republican in each chamber. With this new designation as a clean energy resource, nuclear energy counts toward compliance with the states CES and is eligible to receive local grants that previously were only for solar, wind, and geothermal.  The bill demonstrates Colorado is open for business for advanced nuclear investment, helps the state meet its clean electricity goals, and provides alternative options for local communities historically dependent on legacy energy technologies. CATF played a critical role in helping the bills through committees and ensured the bill preserved the state CES as a technology neutral policy. We also teamed up with local unions to publish a supportive op-ed that highlighted the workforce opportunities as the state transitions away from coal. Learn more about how the bill passed here and here. 

• HB25-1165 established a state entity to oversee and administer long-term carbon storage and stewardship, and it modernized the state’s regulatory structure around geothermal resources. This, too, was a bipartisan bill led by one Democrat and one Republican in each chamber. CATF helped strengthen the bill when it was still in draft form and supported it as it made its way through the legislative process. The bill reflects CATF’s recommendation – provided during testimony last year on a previous version of the bill – that the state finds a solution for long-term stewardship after establishing rules for carbon management. This year’s bill also streamlines regulatory approval for next-generation geothermal technology by eliminating unnecessary permitting steps for superhot dry rock wells. 

• HB25-1292 enables transmission developers to locate high voltage transmission lines in state highway rights-of-way. It provides a solution for grid expansion, avoiding common permitting obstacles associated with private property rights and greenfield development. This bill was led by NextGen Highways, of which CATF is a national and state coalition member. 

Looking ahead, Governor Polis has important opportunities through the rest of his term to cement his legacy: 

• 100% CES by 2040 – The Colorado Energy Office circulated a draft bill in early April to update the state’s existing CES from 80% by 2030 to 100% by 2040, but there was not enough time left in the session for it to move this year. CATF supports the Governor’s desire to update the CES to reach power sector decarbonization by 2040 and looks forward to working with the state and stakeholders in the interim to craft a proposal for the 2026 session that balances ambition with achievability. 

• Methane mitigation from landfills – The Colorado Department of Public Health and Environment proposed a rule to the state’s Air Quality Control Commission that would curb methane emissions from landfills. CATF is working with partners to engage in this rulemaking process over the summer. 

• Optimizing Colorado’s Electric Transmission System – SB25-127 was introduced but did not pass this session. CATF supported this bill, particularly the provision that would designate the Colorado Electric Transmission Authority as the statewide transmission coordinator. This policy would improve transmission permitting processes by enhancing coordination among agencies, recommendations CATF has delivered at both state and federal levels. 

• Renewable Energy and Transmission Siting Study – Last year, CATF supported SB24-212, which directed various state agencies and offices to provide technical support and wildlife management best practices to local jurisdictions seeking to develop renewable energy and transmission projects. It also directed the CEO to provide a report and repository of model codes and ordinances that support renewable energy projects and transmission facilities by September 30, 2025. CATF is part of a state coalition of environmental groups that provides recommendations to CEO as it completes this study. 

• Advancing geothermal – When he served as Chair of the Western Governors Association in 2023, Governor Polis championed geothermal technology and produced the report The Heat Beneath Our Feet, which includes policy recommendations ranging from public funding to regulatory reform to workforce development. Many of these recommendations were geared toward federal level policy, but Colorado has taken steps to implement some of them on its own as well, creating a tax incentive and grant funding program for geothermal projects and updating regulations for example. The state could replenish grant funds that are set to run out this year and could implement other recommendations from the report, such as those that help derisk the upfront cost of exploratory drilling. 

• Transportation decarbonization – Colorado has already enacted several policies to drive down transportation sector emissions in the state, such as adopting Advanced Clean Cars and Advanced Clean Truck rules and robust incentives for passenger EVs. There are additional levers the state can pull to keep this momentum going, like supporting ongoing efforts to reduce indirect source emissions by the Regional Air Quality Council (the lead air quality planning agency for the Denver metropolitan region) and implementing a statewide Clean Fuel Standard. 

As far as state-level climate policy goes, Colorado has made significant and commendable progress already and has laid a solid foundation to build on the next legislative session. CATF looks forward to continuing our work with the legislature, governor, and agencies to advance important climate, clean energy, and public health policies in the state.