OLYMPIA — Washington lawmakers may amend the state’s clean energy law to allow electric utilities to buy coal-generated power as long as they don’t know it’s coal power.

The Clean Energy Transformation Act requires utilities to eliminate coal-fired resources by the end of this year, or pay penalties. To keep rates down and the grid reliable, utilities are backing a bill that would allow them to buy “unspecified electricity” — energy generated by unknown sources and available on the wholesale market.

Northwest Public Power Association executive director Kurt Miller said it’s unrealistic to think some of that power won’t be from coal.

“It’s just the nature of an interstate electric grid connected by thousands of miles of transmission lines,” he said. “As long as there is coal in the system, I don’t think you can ever genuinely say you’re not getting any coal at all.”

Lawmakers passed CETA in 2019, committing the state’s electricity to be free of greenhouse gases by 2045. Being pure will be hard.

House Bill 1329 would clarify utilities can buy unspecified electricity to meet demand, even though some of the electricity may have been generated by coal.

Unspecified electricity makes up a large percentage of the electricity used in Washington. Some 13% of the electricity distributed by utilities in 2022 came from unknown sources, second only to hydropower, according to the state Department of Commerce.

Some 10% of the electricity sold by the Bonneville Power Administration in 2023 came from unknown sources.

BPA does not buy power directly from coal plants, BPA spokesman Kevin Wingert said in an email.

“We do make unspecified power purchases on the market, striving for the most cost-effective purchase to meet our customers’ needs and serve load,” he said. “Those purchases are not linked to an explicit generating source and can come from any number or mix of sources.”

HB 1329 passed the House on a 91-4 vote. The bill is now being considered by the Senate Environment and Energy Committee.