SAN FRANCISCO — A federal appeals court Thursday upheld an energy commission’s finding against several power companies accused of manipulating prices during California’s energy crisis more than a decade ago.

The ruling by the 9th U.S. Circuit Court of Appeals could add more than $200 million to the billions that California has recovered from energy sellers in connection with the crisis.

Energy shortages blamed in part on market manipulation by energy traders plunged parts of California into blackout in 2000 and 2001. The state bought billions of dollars of electricity to keep the lights on.

At issue in Thursday’s ruling was the Federal Energy Regulatory Commission’s determination that Shell Energy North America and several other companies violated laws, raising energy prices.

The 9th Circuit said the commission didn’t abuse its discretion in making that ruling.

Shell disagreed, saying in a statement that it supplied much-needed electricity to California in full compliance with regulations as it “reasonably interpreted them at the time.”

The company was accused of multiple violations, including disguising electricity sold in California as coming from out of state — a tactic that allegedly allowed it to avoid price caps.

California Attorney General Kamala Harris said in a statement she was pleased with the court’s decision.

“My office will continue to pursue compensation from those who gamed the market and profited from the skyrocketing prices that resulted,” she said.

The state has previously settled claims against dozens of energy sellers in connection with the energy crisis, resulting in billions of dollars in refunds to California consumers.