The California power grid will be strained again Thursday during what is expected to be the highest electricity demand of the year as scorching temperatures continue, power officials said. Utilities in the state say their systems are largely holding up well under the strain, with only scattered outages. A part of downtown Los Angeles was without power for more than two hours Thursday morning, with power restored around 5:30 a.m. PDT.

Carol Tucker of the municipal utility Los Angeles Department of Power and Water said during the power outage that it was not yet known whether the failure was related to the high demand and high heat this week. About 10 buildings, including at least three major downtown office towers, some hotels and apartment buildings, were affected by the short early-morning blackout.
The LADWP, the largest municipal utility in the United States, is expected Thursday to have its highest demand of the year at 5,826 megawatts, topping Wednesday's demand peak of 5,781 megawatts. A megawatt can power about 650 homes in Southern California under normal conditions.

The state's largest utility, investor-owned Pacific Gas & Electric Co., a subsidiary of PG & E Corp., said lightning strikes were the main cause of about 10,000 customers losing power Thursday morning. Southern California Edison, a subsidiary of Edison International, said about 1,000 customers were without power Thursday morning. Mashi Nyssen of So Cal Ed said the outages were caused by a lightning strike.

Throughout California and the US Southwest, power demand Thursday is expected to near highs for the year. During Wednesday's peak demand, the California power grid was strained but did not suffer power outages, said officials with the grid manager, California Independent System Operator. The Cal ISO called a "Stage 1 power emergency" Wednesday, which means the reserve margins for power on the state grid were less than 7 percent. So far, only voluntary conservation measures have been called, but if the power available dips below 5 percent, a "Stage 2" emergency may be called. If that happens, some business customers who have signed up for lower rates will be forced to cut power use.

The most serious phase, Stage 3 power emergency, has not been called since May 2001. It would cause rolling blackouts. The Cal ISO said Wednesday a Stage 3 emergency was not expected this week. California's power grid Wednesday afternoon hit a demand high for the year, at 48,538 megawatts on Wednesday afternoon. Thursday's forecast peak is almost 50,000 megawatts. The record use for the Cal ISO came last July at 50,270 megawatts.
(By Bernie Woodall, Planet Ark, 31/08/2007)