It's one more step forward for a plan by Arizona's largest utility to restructure ownership of a coal-fired power plant it operates in northwestern New Mexico.
Arizona utility regulators have approved Arizona Public Service Co.'s purchase of Southern California Edison's 48 percent share of two units at the Four Corners Generating Station.
The $294 million deal still needs approval from federal regulators, but the Arizona utility expects to close on the sale later this year.
APS announced plans in 2010 to seek majority ownership of the two units and shutter the plant's other three, more polluting generators.
APS proposed the buyout as a result of Southern California Edison's decision to terminate interest in the plant to comply with California laws that prevent utilities from investing in most coal-fired plants.
A federal proposal to upgrade the plant to reduce nitrogen oxide emissions also was a factor.