A federal plan to grant electric-vehicle makers credits for charging vehicles with renewable gas-generated power could be delayed over legal challenges, Reuters reported.

The credits, which would also allow credits for methane gathered from landfills and cattle farms, would have been an automotive industry add-on to the existing U.S. Renewable Fuel Standard, Reuters said. The Environmental Protection Agency recommended the plan last year.

The standard mandates that oil refiners add biofuels to their fuels or purchase credits from fellow refiners that do so, Reuters said.

The government could split off the EV program from overall credit issue quotas, whose deadline is in June, in order to prevent legal challenges to the auto add-on from scuttling other credit quotas, the news service reported.

Reuters said the House of Representatives Energy and Commerce Committee has protested autos being added to the RFS program, saying it’s meant for liquid transportation fuel and not to electrify transportation, which is a goal of the Biden administration.

The EPA’s recommendation to add vehicles to the RFS estimated EV makers could get as many as 600 million credits next year, Reuters reported, a number that the agency expected to grow exponentially.

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