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Climate Action Tax

Boulder’s Climate Action Plan (CAP)

Preserving the health and sustainability of our climate has been valued by our community for many years. Boulder’s Climate Action Plan, often referred to as the CAP, is a set of aggressive, city-funded programs and services designed to reduce local greenhouse gas emissions and mitigate climate change. As a result of CAP-funded programs, Boulder avoided more than 60,000 metric tons of emissions between 2007 and 2017, keeping our community emissions fairly constant despite growth in population, jobs and economic activity.

Our goal now is to build on this success and foster economic vibrancy while reducing overall emissions by 80 percent by the year 2050. Reaching this goal means ramping up our climate efforts and in particular, our actions to promote energy efficiency and conserve natural resources.

What’s the CAP tax?

In 2007, Boulder passed a Climate Action Plan (CAP) tax—the nation’s first voter-approved tax dedicated to addressing climate change. The CAP tax is levied on city residents and businesses and is based on the amount of electricity they consume. Tax rates are different for each of three sectors, listed here with their average yearly amount: residential ($21), commercial ($94), and industrial ($9,600). The CAP tax generates approximately $1.8 million each year.

In 2015, Boulder voters approved a continuation of the CAP tax through March 31, 2023. The current tax rates and collection mechanism will remain the same. 

Read our CAP at a Glance pdf handout to get a brief overview of the CAP tax and programs.

Read more about the History of the CAP tax pdf and background in Boulder’s Carbon Tax: Building a Foundation for Community Climate Action pdf.  

More about climate action

Overall CAP accomplishments

  • Stopped the growth of greenhouse gas emissions and achieved real emissions reductions
  • Helped thousands of residents and businesses implement energy efficiency improvements at home and at work
  • Significantly increased the number of property owners and tenants investing in, and benefitting from, energy efficiency programs
  • Earned Boulder one of highest rates of installed solar capacity per capita in the United States, and recognition as a Platinum-level Solar Friendly Community
  • Piloted new programs and approaches that have been replicated across Colorado

Current CAP programs and accomplishments

The current 2015 CAP tax revenue funds a variety of effective efforts and is currently allocated to:

  •  EnergySmart energy advising services and rebates for residents
    • More than7,500 city of Boulder housing units have participated in EnergySmart since the program’s inception in 2010.
    • More than $1.4M in rebates have been paid and over $10.5M in private investments have been made.
  •  SmartRegs energy efficiency requirements for rental properties
    SmartRegs requires that all rental housing units comply with energy efficient requirements by December 21, 2018. 
    • The SmartRegs program recently surpassed a “stretch goal” by reaching 3,000 compliant rental units in a one-year contract period between February 2014 and March 2015
    • More than 7,600 rental units (out of about 20,000) are now compliant with SmartRegs
  • Pilot programs that spur market innovation and local renewable energy generation
    • Boulder Energy Challenge grant program has provided $300,000 funding for innovative solutions from the community to reduce emissions
    • Boulder Rooftop Solar Tool will assist residents, businesses and property owners in understanding their unique solar potential.  Launching August, 2015
  • Programs and policies designed to improve energy efficiency in commercial properties  
    • EnergySmart for Businesses pdf: More than 2,300 city of Boulder businesses have participated in EnergySmart since 2010. More than $2M in rebates have been issued and more than $7.5M in private investments made
    • Building Performance Ordinance: This proposed ordinance would require owners of large commercial and industrial buildings to annually rate and report their buildings’ energy use, and perform periodic energy efficiency measure
  • Program tracking, reporting and evaluation
    • Tracking community greenhouse gas emissions using a new international standard used by other global cities. Latest GHG inventory completed for 2012
    • Development of a sustainability data tracking, management and reporting system
    • Development of a roadmap to reduce greenhouse gas emissions in collaboration with community partners and experts

Boulder's Climate Leadership

A number of successful programs and services born from the CAP tax and developed in Boulder have since been adopted by other cities and organizations. EnergySmart’s energy advisor model is now used by organizations nationwide. Boulder’s Small Building Tune-Up pilot (2010-2013) encouraged Platte River Power Authority and Xcel Energy to launch utility incentive programs now available to thousands of customers across the state.

Frequently Asked Questions

What does the CAP tax fund?

  • The CAP tax funds programs and services to reduce GHG emissions by encouraging residents and businesses to reduce energy consumption, save money on energy costs over time, and minimize reliance on external energy sources. Programs and services are periodically evaluated and adapted to be most effective and meet the needs of the community.

How much do I pay for CAP tax?

The average residential account pays approximately $21/year toward the CAP tax. Because the CAP tax is based on carbon consumption, payment depends on how much electricity each customer uses. The tax rate and average annual CAP tax per sector:

Current CAP Tax Rates

    Electricity User Type    

      Tax Rate      

    Average Annual Tax    


$0.0049 /kWh



$0.0009 /kWh



$0.0003 /kWh



How has my CAP tax been spent?

  • Business programs offered include:
    • LED Exit Sign Exchange / 2007
    • ClimateSmart at Work Audits / 2007-2009
    • Small-Building Tune-Ups / 2010
    • 10 for Change / 2008-2014
    • Commercial EnergySmart (Partners for a Clean Environment) / 2011-present

    Residential programs offered include:

    • Weatherization / 2007
    • LED holiday light exchange / 2007-2008
    • Efficient Lighting Coupons / 2007-2008
    • Multifamily Performance Program / 2007-2009
    • Neighborhood Sweeps / 2007-2010
    • Solar Thermal and Insulation rebates / 2008
    • CU’s Energy Green Teams and Greek Sustainability Program / 2010-present
    • ReNew Our Schools PTO Fundraiser / 2011
    • Residential Energy Action Program / 2008-2010
    • Residential EnergySmart, including support for SmartRegs compliance / 2011-present
    • Boulder Energy Challenge / 2013-present
    • Boulder Building Performance Ordinance (proposed) / present

How is the CAP tax collected?

Currently, Xcel Energy collects the tax for the city through its monthly customer utility billing. Customers who subscribe to wind-generated power through Xcel Energy's Windsource program are not taxed for that portion of their electricity use. If during the CAP tax is extended and during the new tax period the city begins operation of a municipal electric utility, the new utility could either continue collection of the tax under the current system or sunset the tax and fund efficiency and conservation programs through its rate structure or other means.

Why should we care about greenhouse gases?

Greenhouse gases (GHGs) absorb radiation from the sun and trap heat in Earth’s atmosphere. The more GHGs we emit, the more heat is trapped in our atmosphere, leading to global warming, climate change, and weather related disasters such as increased flooding and wildfires.

Currently, our community has a big emissions footprint: 99 percent of Boulder’s emissions come from burning fossil fuels to produce electricity, provide heat and power our transportation system. Each year, our community adds a total of 1.95 million metric tons of carbon to Earth’s atmosphere, or roughly 19 metric tons per person. In order to reach our community climate goals and address the climate challenge, we need to change how we produce, manage and use energy by becoming more efficient, conserving natural resources, and creating energy systems that are clean, affordable and reliable.

Want to know more about the CAP tax?

Visit . Contact us via Inquire Boulder or at [email protected] with any questions or feedback you may have.

For billing questions, please contact Xcel Energy at (800) 895-4999.

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