Solarium has agreed to pay a $4.3 million settlement to resolve allegations that it violated the federal Renewable Energy Incentive Act by illegally transferring millions of dollars in renewable energy credits from one solar energy project to another, according to a federal law enforcement official familiar with the matter.

The settlement, reached in September, covers the Solarium project in the Denver-based Denver-area town of Green River, the official said, declining to be named because the settlement is ongoing.

The federal law, known as the Renewable Electricity Incentives (REIA) Act, requires a project developer to sell energy credits that come with a renewable energy price, known in the industry as a renewable portfolio standard (RPS), for a specific period of time, and then to recoup the credits.

The Solarium program was part of the federal renewable energy incentives program that President Donald Trump established in 2018.

A spokesperson for the White House did not immediately respond to a request for comment.

Under the federal program, which runs through 2024, the U.S. Department of Energy will pay Solarium up to $2 million per year in renewable credits that it sells to the federal government.

Solarium said it would recoup its $2.5 million payment.

Under federal law and the Renewables Based Renewable Fuels (RBRF) Act passed by Congress in 2020, companies with renewable energy projects have to recontribute their energy credits in a manner that is not subject to the RPS.

The company was also fined $3.5million in 2018 for violating the Renewed Energy Inertia (RESI) law by selling credits for renewable energy to third parties.

Under RESI, the government does not require a project to recode, which is required for renewable credits to be recontributed.

The U.K.-based company agreed to a $5.5m penalty, with $1.1m of that paid into a trust, the Department of Justice said.

The Department of Homeland Security said it had fined Solarium $5,000 in 2018 and 2019, and ordered it to repay $3,000.

A spokeswoman for Solarium did not respond to requests for comment on the settlement.