Weather puts heat on power supplies
A coastal heat wave pushed electricity demands for the San Diego area to near-record levels on Monday.
San Diego Gas & Electric deployed a suite of incentives that reward utility customers for reducing their power use in the crucial afternoon and early evening hours. The utility and other grid managers stopped short of emergency measures, like interrupting service to large power customers under special contract provisions.
Mid-afternoon temperatures at the harbor-side San Diego International Airport reached 86 degrees with 60 percent humidity on Monday, well above the seasonal average of 77 degrees. In the desert at Borrego Springs, the temperature was 104 with 20 percent humidity.
“We definitely have adequate resources” to meet electricity demands, said Erin Coller, a spokeswoman for San Diego Gas & Electric, the investor-owned utility serving San Diego and southern Orange counties. “We are in the range of reaching an all-time peak (power demand) today and tomorrow.”
Responding to weather and power forecasts, SDG&E opened up a temporary conservation incentive called “reduce your use” to all residential customers on Monday and Tuesday. The program provides a 75 cent credit per kilowatt hour of energy conservation between 11 a.m. and 6 p.m. Customers register online to become eligible, a step that has shown to increase energy-saving efforts, Coller said.
Standard residential electricity prices in San Diego range from 17 cents to 39 cents per kilowatt hour, with the average customer using about 500 kilowatt hours each month.
Statewide power reserves were more than 7 percent in excess of demands, the initial threshold for emergency measures. The state’s main grid manager, the California Independent System Operator, also stopped short of calling an urgent public appeal for conservation known as a flex alert. Rolling power outages are not instituted until reserves drop below 3 percent.
The most recent flex alert was issued in February when Southern California power plants experienced a shortage of natural gas because of cold weather and soaring fuel consumption in the eastern U.S. There were two flex alerts last year in response to hot weather, along with a third in response to the sabotage of the Metcalf substation south of San Jose.
California’s peak power use has fallen steadily since 2006. Not so in San Diego, where the power demands of a densely populated coastline still strain the grid on hot days as usuall dormant air conditioners are activated.
SDG&E recorded an all-time peak demand of 4,687 megawatts for its territory on Sept. 27, 2010. Demand surged to similar heights last year, reaching 4,603 on Aug. 30.
SDG&E set out to reduce power demands by about 60 megawatts on Monday through incentivized programs aimed both household and business customers.
The state of California treats timely conservation of electricity much like an emergency power plant, paying for people to turn up the thermostat, cycle off air conditioners or devise their own power saving strategies.
SDG&E’s residential utility customers stood to save as much as $1.25 per kilowatt hour by installing a smart thermostat that can be programmed by remote control — and called upon to reduce energy demands from air conditioning when demands on the grid are heaviest.
