Washington state took in $62.4 million last week in an emergency cap-and-trade auction, raising the amount it has collected this year by taxing carbon emissions to $919.5 million, according to figures released Aug. 16 by the Department of Ecology.

Buyers snapped up more than 1 million allowances at pre-set prices. Half sold for $51.90 each and half sold for $66.68 apiece.

Based on the carbon content of fuel, allowances that sold for $66.68 can be expected to add about 53 cents to a gallon of gasoline, according to a formula cited by the California Air Resources Board.

The formula does not take into account individual business decisions by fuel producers. Allowances in California, which pioneered cap-and-trade, sold for $30.33 in May.

Washington’s cap-and-trade auctions have been competitive. Last week’s auction was triggered by unexpectedly high bids at an auction in May, when investors bought 10% of the allowances.

Cap-and-trade makes carbon emissions an expense that fossil fuel suppliers must absorb or pass on to customers. Cap-and-trade also creates a commodity, allowances, which can be sold on a secondary market.

Allowances were selling for an all-time high of $67.50 in early August, according to Aegis Hedging.

The auction last week was closed to investors to give energy suppliers a chance to acquire allowances without bidding against investors.

Some 32 energy suppliers, including oil companies and municipal natural gas utilities, registered to participate in the special auction. Ecology does not announce the successful bidders.

Since cap-and-trade went into effect Jan. 1, gasoline prices in Washington have risen by $1.25 a gallon, compared to increases of 76 cents a gallon in California and 88 cents a gallon in other Western states, according to the U.S. Energy Information Administration.

Over the past year, gasoline prices nationwide have fallen by 70 cents a gallon, but in Washington have risen by 23 cents a gallon, the most in the U.S., according to AAA. Over the same period, Oregon gas prices fell by 16 cents a gallon.

The auctions also could push up natural gas prices. Some energy suppliers have indicated they will seek to recoup the money from ratepayers, according to filings with the Securities and Exchange Commission.

Ecology plans to auction 8.5 million more allowances Aug. 30. The final auction of the year is set for Dec. 6.

The state has already collected more than twice as much money as it anticipated for 2023 when lawmakers passed cap-and-trade in 2021.