RGGI & state carbon markets

The short version

State and regional cap-and-trade programs put a price on CO2 emissions from power plants by requiring generators to hold allowances for every ton emitted. The Northeast's RGGI program, California's economy-wide cap-and-trade, Washington's Climate Commitment Act, and New York's emerging Cap-and-Invest (NYCI) all use this approach. The economic effect: carbon costs are embedded in wholesale electricity prices because the marginal generating unit (typically natural gas) must factor allowance costs into its bid — which then sets the market clearing price for all generators dispatched.

RGGI mechanics and membership

The Regional Greenhouse Gas Initiative launched in 2009 as the first US power-sector carbon market. The program currently covers 10 states: Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island, and Vermont. Virginia joined in 2021, left in 2024, and is rejoining for the second half of 2026 (covering only its second-half 2026 emissions). Pennsylvania left RGGI on November 12, 2025 following protracted legal challenges to the executive order under which Governor Wolf had joined the program.

Power plants over 25 MW in RGGI states must hold one allowance for each short ton of CO2 emitted. Allowances are sold at quarterly auctions; states use the auction revenue to fund energy efficiency programs, renewable energy deployment, beneficial electrification, and direct bill assistance for low-income customers. The cap declines over time — currently scheduled to fall 30% from 2020 to 2030 — creating progressively tighter supply that drives prices higher.

How RGGI shows up in your bill

The pass-through mechanism is fundamental to understanding RGGI's economic impact. In wholesale electricity markets like NYISO and ISO-NE, the marginal generator — usually natural gas — sets the clearing price for the entire market. That marginal generator must purchase allowances to cover its emissions, and embeds the allowance cost in its bid. When the bid clears the market, every generator dispatched receives the marginal price — including renewables, nuclear, and hydro that don't pay for allowances.

The result: total customer cost of RGGI is substantially larger than direct allowance purchases. Direct allowance auction revenues run roughly $1 billion per year across RGGI states; analyses estimate the pass-through effect roughly doubles or triples that impact on customer bills. For a large industrial customer in a RGGI state, RGGI may add $1-3/MWh to wholesale energy costs depending on the local generation mix — meaningful but not transformational at current price levels.

California, Washington, and the next wave

California's cap-and-trade program is broader and stricter than RGGI — economy-wide rather than power-only, covering industrial sources, fuel distributors, and electricity importers. California allowances are linked with Quebec, creating a combined market with deeper liquidity. Recent auction prices have run $25-30/ton, with the program reauthorized through 2030 and California currently considering extension through 2045 with tighter caps.

Washington's Climate Commitment Act (CCA) launched in January 2023, ran into political turbulence with a 2024 ballot initiative challenge (which the program narrowly survived), and continues operating with adjusted market design. New York's Cap-and-Invest (NYCI) is part of CLCPA implementation; pre-proposal materials modeled allowance prices in the $14-25/ton range for 2025 escalating to $25-54/ton in 2027, but implementation has been repeatedly delayed and regulations remain in development. For commercial buyers operating across multiple states, these carbon market programs create a patchwork of carbon costs that vary substantially by location — typically adding $1-5/MWh to electricity costs in covered states.