Heat Wave Strains California Power System
Date: 31-Aug-07
Country: US
Author: Bernie Woodall
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.