US energy company El Paso illegally held back supplies of natural gas to drive up prices at the height of the 2001 California energy crisis, regulators say.
The Federal Energy Regulatory Commission's chief judge, Curtis Wagner, said the Texas-based company should be penalised for abusing its market power.
The FERC has been investigating El Paso and a group of other companies suspected of exacerbating the electricity shortages which triggered rolling blackouts from mid-2000 through 2001.
Natural gas is a common fuel for California electricity generating plants, and a massive hike in prices was a contributing factor in the state's crisis.
Europe has recognised the need for negotiations with Russia to discuss the security system on the continent. Russian Foreign Minister Sergei Lavrov is going to Macedonia for meetings with colleagues within the OSCE