Extreme heat continued yesterday in the Pacific Northwest andArizona and above normal temperatures arrived in New England,prompting the California Independent System Operator (Cal-ISO) andthe New England ISO to issue calls for conservation and to warn ofshort supplies.

It was the second consecutive day for the Cal ISO to issue apower alert and keep a wary eye on its statewide grid, which wasexpected to struggle under peak load conditions and constrainedgeneration options. With the state’s power reserves dropping below5% and a sweltering heat wave still baking the region, the ISOdeclared a “Stage II Emergency” yesterday afternoon and called uponSouthern California Edison (SCE), Pacific Gas & Electric andSan Diego Gas & Electric to begin voluntary load curtailmentprograms for certain interruptible customers within their serviceareas. By mid-day temperatureseased along California’s coastalregions, helping to slow demand, but utility officials were stillholding their breath and probably will through Thursday.

“We’re issuing a call to action, a call that everyone needs totake seriously,” said Pam Bass, SCE’s senior vice president forcustomer service. “If the demand for power does not decrease soon,we will be ordered by the state to begin shutting off power forblocks of customers. Everyone needs to reduce their use of powernow to avoid forced outages.”

PG&E’s utility was seeking to curtail 500 MW from a littlemore than 200 customers, and Southern California Edison was lookingfor 447 MW of curtailed load among some of its large customers. SanDiego Gas and Electric Co. sought something roughly half that size.

“Operating reserves for much of the western United States areslim due to the widespread heat,” Cal-ISO officials said in callingthe second-stage alert. “Electricity imported by California fromthe northwest is particularly scarce.”

Under normal conditions, the projected peaks-still 2,000 to3,000 MW short of last year’s one-day record-would not be aproblem, but the amounts of power that California can import thisweek have been severely restricted, according to Cal-ISO officials,who indicated the state was getting about 20 percent of its normalsupplies from the north. About 1,500 MW worth of power isunavailable in Oregon-Washington because of forced outages andrecord high temperatures in Portland and Seattle.

The situation in the Pacific Northwest was even more constrainedfollowing the outage of Energy Northwest’s 1,085 MW ColumbiaGenerating Station, which experienced a turbine failure on Mondayand was shutdown Tuesday. Spot power prices at Mid Columbia werereported near $800/MWh.

Under the Cal-ISO procedures, Stage Two alerts are called whenoperating reserves dip below five percent or are expected to do sowithin a two-hour time frame. The alert was kept in effect duringthe peak load hours of 1 to 7 p.m. on Tuesday.

“It is hotter today (Tuesday) in the Northwest than it wasyesterday; Portland may hit a record of more than 100 degrees orhigher,” said Patrick Dorinson, Cal-ISO’s communications director.”Seattle is headed for the nineties. The generating units out ofservice normally help the transfer of power to us, and withoutthem, it limits that ability. So, in order to operate the systemreliably in the north, they can’t export as much to us.

“The amounts they can export are extremely limited, plus thetemperatures put more demand on them locally. This is the situationwe have been talking about: we are interconnected in the West.We’ve got high temperatures all over the bigger region, and you putall of that together and it makes for a difficult day.”

There are similar limitations on imports from the Southwest, butthose are strictly because of extremely high temperatures — notunits being out of service. Phoenix, AZ, experienced temperaturesaround 120 degrees on Monday.

For California, the limitation on its ability to import powerfrom out of state is worsened by the fact that for the past fewweeks it has had a combination of in-state generating units,totaling about 2,500 MW out of services. “Some is due to forcedoutages, some are planned maintenance and still others areoperating, but with limited output,” said Dorinson, noting theaffected units are pretty widely dispersed around the state,compared to two weeks ago when they were concentrated more in thegeneral San Francisco Bay Area and resulted in rolling blackouts.

Dorinson said the Cal-ISO is not anticipating the need for anyrolling blackouts in the current situation, but he admitted that ifthe state experienced additional forced outages of plants in themiddle of the day, there would have to be the planned blackouts —voluntary curtailments, alone, wouldn’t suffice most likely.

“Once again, this (week) is just another part of the puzzle,”Dorinson said. “No two summer situations are alike.”

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