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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 ~250,000-750,000 cumulative metrics tons (MT) of GHG emissions since 2007, keeping our community emissions fairly constant despite growth in population, jobs and economic activity. See more about Boulder's GHG reductions on the community GHG emissions dashboard.

CAP Tax has generated $17.3 million in revenue which has funded policies, programs, direct advising services and rebates to homes and businesses. While it’s nearly impossible to determine what avoided load growth and emissions savings can be directly attributable to CAP Tax programs and staff efforts, the community has reduced GHG emissions from 2005 levels by 16 percent, even with the addition of 7,500 jobs and a 57 percent increase in gross domestic product (GDP).

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 below numbers are current as of Dec. 2018. The current CAP tax revenue funds a variety of effective efforts and is currently allocated to:

  •  EnergySmart energy advising services and rebates for residents
    • More than 11,000 City of Boulder housing units have participated in EnergySmart since the program’s inception in 2010.
    • More than $1.8M in rebates have been paid and over $16.7M in private investments have been made.
    • Over 16,000 MTCO2e have been reduced to date from these upgrades, with an anticipated lifetime impact of 65,000 MTCO2e reduced.


  •  SmartRegs energy efficiency requirements for rental properties
    SmartRegs requires that all rental housing units comply with energy efficient requirements by December 31, 2018. 
    • More than 20,500 rental units (out of about 23,000) are compliant with SmartRegs
    • More than $880K in rebates have been paid and over $6.7M in private investments have been made
    • Over 14,000 MTCO2e have been reduced to date from these upgrades, with an anticipated lifetime impact of 56,000 MTCO2e reduced.


  • Pilot programs that spur market innovation and local renewable energy generation
    • Boulder Energy Challenge grant program has provided over $490,000 funding for innovative solutions from the community to reduce emissions
    • Growth of the Comfort365 program has provided ongoing support to homeowners adopting heat pumps as natural gas replacement alternatives
    • 48 City operated electric vehicle charging stations are available for public charging


  • 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 $3.3M in rebates have been issued and more than $17.9M in private investments have been made
    • Building Performance Ordinance: Launched in 2015, the ordinance requires owners of large commercial and industrial buildings to annually rate and report their buildings’ energy use, and perform periodic energy efficiency measures. The ordinance has experienced a 99% compliance rate since implementation, covering over 32 million sqft of commercial building space
  • Program tracking, reporting and evaluation
    • Tracking community greenhouse gas emissions using a new international standard used by other global cities. As of the 2017 completed inventory, community emissions have been reduced by 16.2% from a 2005 baseline. 
    • 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​


​Additionally, 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 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/ 2011-current
    Boulder Energy Challenge / 2013-2017
    Boulder Building Performance Ordinance / present

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 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 Renewable Connect program are not taxed for that portion of their electricity use. Xcel will no longer charge the CAP tax when the solar systems go into service. If 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.

Where can I find past evaluations of CAP Tax?

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.