Boulder voters in 2006 approved the nation's first municipal carbon tax, the Climate Action Plan (CAP) Tax, charging electricity users by kilowatt-hour to fund climate programs, and renewed it in 2022 through 2040.
The CAP Tax (BRC §3-12) launched in 2007 as the first US city carbon tax, levied on electricity consumption to fund Boulder's climate goals. Residential, commercial, and industrial customers pay graduated rates per kilowatt-hour through Xcel Energy bills. Voters renewed and expanded the tax via Ballot Issue 2A in 2022, merging it with the Utility Occupation Tax and extending collection to 2040. Revenue funds energy efficiency rebates, renewable energy projects, transportation electrification, and resilience programs. Boulder targets 100% renewable electricity citywide and net-zero greenhouse gas emissions by 2035.
Residents do not pay penalties directly; tax appears as line item on Xcel utility bills and is collected automatically by the utility on behalf of the city.
See how Boulder's climate emergency mobilization rules stack up against other locations.
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