LOS ANGELES - California's power grid strained under the demands of air conditioners Wednesday as a heat wave gripped the West, leaving little electricity to spare in the region.
A power emergency was declared for the second consecutive day, triggering prearranged voluntary cutbacks by large customers - a step taken to avoid rolling blackouts.
The mercury climbed to the upper 90s and over 100 in many parts of the state, and the heat was compounded by moist air from the Pacific that made some areas feel like the tropics.
Demand for electricity rose toward record levels, according to the California Independent System Operator, which directs electricity to 75 percent of the state's power grid.
Officials urged people to reduce power consumption by closing drapes or blinds to keep out sunlight, refrain from opening refrigerators, cook and do laundry during off-peak hours and to use fans instead of air conditioners.
''You have a demand in California and the entire West is outstripping the supply,'' said Patrick Dorinson, an ISO spokesman.
California's 1,100 power plants generate about 54,000 megawatts a day. The state also imports about 25 percent of its annual energy needs from the Pacific Northwest and the Southwest, said Claudia Chandler, spokeswoman for the California Electricity Commission. But the state still faces a shortage.
''We all face a heat wave that extends from Washington to Texas and there's not as much electricity available from neighboring states to serve California's power needs,'' Chandler said.
The state hasn't built new power plants in about 20 years and has averaged about 485,000 new residents each of the last five years. Four plants are under construction and nine others are planned. The first new plant won't begin operating until next year.
Chandler said, however, that the state ''may not be able to build our way out of this situation.''
Intense heat occurs typically about 15 days a year, and building power plants just for those occasions might be a very expensive approach.
The Electricity Commission is instead looking at ways to increase conservation.
''If we can set the standard to make sure that new buildings have the most efficient lighting and air, good orientation like where the windows are placed, and insulation, those are the things that pay back for years to come,'' Chandler said.
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On the Net:
California Independent System Operator: http://www.caiso.com