"What's the responsible action?" asked Barry Wallerstein, the air district's executive officer. "Should we wait until we have brownouts and blackouts to build new power plants? We need lights in our schools and power for our factories and electricity in our homes."
Wallerstein said the region needs about 2,000 megawatts of new capacity, and that sufficient offsets are unavailable on the open market.
The 32-page decision came in response to a lawsuit filed by the Natural Resources Defense Council, Communities for a Better Environment and other groups. In it, Judge Ann I. Jones told the air district it could not sell offsets to the plants without a fuller analysis under California's Environmental Quality Act. In particular, the judge said, the district needed to analyze exactly how many tons of pollutants, including health-damaging soot and planet-heating greenhouse gases, each proposed plant would emit.
Wallerstein said the district is unlikely to appeal the ruling. "It will be a question of whether we proceed with a new rule, or whether we throw up our hands and say, someone else should figure this out because it is beyond our control."
If the judge's concerns "are beyond our ability to address, then there will be a permanent moratorium on power plant construction in Southern California."
Environmentalists and many industry experts say that much of the region's demand can be met through conservation and renewable energy.
But no one knows how much could be supplied by wind farms, geothermal energy, solar rooftop facilities or large solar plants, many of which are proposed in fragile desert areas.
Until the 1998 electricity deregulation, the state's Energy Commission was responsible for determining needs. But later, the commission's role was largely reduced to permitting the siting of plants, leaving the market to decide how much and what kind of generation is needed.
Southern California Edison has signed long-term power purchase agreements for 2,556 megawatts of power from new gas-fired generators, including proposed plants in Walnut Creek, Calif., and El Segundo. Spokesman Gil Alexander said Wednesday that the company had not assessed the effect of the judge's decision.
"Obviously we believe new capacity is a critical energy planning issue for the region," he said.
