Power grids in California, Nevada and Arizona last week fended off soaring temperatures and a resulting flood of demand for electricity. Power providers in Nevada and Arizona were reporting new records for system peaks, while the California Independent System Operator (CAISO) declared restricted maintenance days for power facilities and asked Californians to reduce energy usage.
CAISO asked all Californians to reduce energy usage for the afternoon of July 14. That was the fourth day of the first major heat wave this summer.
Specifically, CAISO declared Thursday a "Flex Your Power NOW!" day. The Flex Your Power NOW! alert notifies California businesses, governments and residents when they should follow specific conservation and load-shifting measures to immediately reduce their electricity use.
In a conference call on Thursday with reporters related to the ISO's recently announced corporate realignment (see related story), CAISO spokesperson Stephanie McCorkle said that "we are experiencing still this first real dose of summer -- our first heat wave. And the fact that we're seeing these kind of high loads is something that we factored into our summer assessment."
"This year's situation is better than last year, even though we're breaking records again," said Yakout Mansour, the CEO of CAISO, on the conference call. Among other things, Mansour noted that the amount of generation capacity added in the state has been increasing and various transmission constraints are being resolved.
Unexpected cloud cover over the southern part of California on Thursday helped to cut demand for power on CAISO's electric system and allowed the grid operator to avoid having to face new peak demand records. But California's not out of the woods just yet, with sizzling temperatures expected to continue blanketing the state.
"We did not set a new record yesterday [July 14]," CAISO spokesperson Gregg Fishman told NGI on Friday. "We did expect to," but there was some cloud cover that moved in over Southern California "that was not anticipated and that lowered temperatures there and reduced demand on our system considerably."
For Friday, "we're expecting high demand again, but not recordbreaking," Fishman noted. Friday (July 15) was also designated a Flex Your Power NOW! day. The forecasted peak demand for Friday was 44,833 MW. "We're trending right about on target -- maybe just a tad under -- but it's early and that can fluctuate quite a bit either way," he said in an interview just after 10:00 a.m. PST on Friday.
"Over the weekend and into next week, the heat wave that we've been experiencing is expected to continue," the CAISO spokesperson said. "We don't keep really close track of weekend peaks, but we're probably going to set new record peaks for weekend demand Saturday and Sunday. It'll be high -- it won't be the all-time record peak, but for weekends we're seeing very high loads."
For Monday, July 18, "it's a little too far out to start predicting, but the heat wave continues and we are expecting high demand again. How high? We'll have a better idea of that on Sunday," Fishman said.
He also said that CAISO, as of Friday, was continuing to restrict maintenance on power facilities in the state. "That's a fairly standard thing we do when we see high demand," Fishman noted. "It's just asking generator and transmission owners -- 'don't do anything to your facilities or your systems that would increase their risk of tripping.'"
Pacific Gas and Electric Co. on Thursday said that it was voluntarily curtailing usage at its facilities throughout northern and central California. The utility urged its customers to take part in CAISO's call to action and conserve electricity on Thursday.
Meanwhile, Sierra Pacific Power on Thursday reported that a record electric system peak of 1,716 MW was recorded at 5 p.m. that day, the third record set in as many days. The company said that above-average temperatures forecasted for this week could produce more record electric system peaks in the days ahead.
The company attributed the string of records to increased use of air conditioning equipment and new customer growth. Previous system peaks were set last Wednesday at 1,698 MW; last Tuesday at 1,686 MW; and 1,657 MW set on July 30, 2003.
Sierra Pacific Power's service territory covers approximately 50,000 square miles in northern Nevada including the cities of Reno, Sparks, and the Lake Tahoe area of northeastern California.
Arizona's Salt River Project (SRP) on Tuesday delivered a record amount of energy to its Phoenix-area retail customers. Between 4 and 5 p.m, SRP delivered an estimated retail peak demand of 5,756 MW.
That peak topped the previous SRP high for this year, 5,671 MW on June 21, and last year's peak demand of 5,665 MW on August 11.
SRP said that strong customer demand is the result of several factors, including an increase in the number of SRP electric customers, extreme daytime temperatures, higher overnight temperatures and relatively high humidity. The high temperature recorded in Phoenix on Tuesday was 115 degrees, while the overnight low was 83 degrees.
SRP said that the newly completed unit at the Santan Generating Station in Gilbert as well as the recent purchase of the Desert Basin Power Plant near Casa Grande will help ensure that SRP has enough energy to meet the needs of its customers this summer.
At the Law Seminars International conference on "Energy in the Southwest" in Santa Fe, NM, an SRP official said that SRP set record daily peaks Wednesday and Thursday, exceeding 5,800 MW and heading toward 6,000 MW, which the utility was gearing up for this summer.
SRP is the largest provider of electricity in the greater Phoenix metropolitan area, serving nearly 860,000 customers.
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