Ann de Rouffignac
OGJ Online
The California Independent System Operator called a Stage One emergency Monday because of high winter demand and the sudden loss of about 400 Mw of generating capacity.
With continued high demand in winter, the electricity system can be thrust into an emergency with the loss of as little as 400 Mw, says Stephanie McCorkle, spokeswoman for the California Independent System Operator.
On Monday, demand was forecast at 35,071 Mw and a 400 Mw power plant in PG&E�s service territory was forced off line. California ISO officials expect the peak demand Monday could surpass the all-time winter record for California. Stage One means there is insufficient operating reserves for the forecast peak load and warns utilities to prepare to ask for interruptible load if called upon to do so.
�It�s hard to say yet if we will have to ask for interruptible load yet,� she says. �Supply is extremely tight.�
Two transmission lines, one a 230 kv and the other a 150 kv line, had to be derated because of weather related problems, she says. The transmission problems could have caused that plant to trip, she says. Further details were not available.
The problem in California is inside the state this time. Exports to California from the Northwest are holding fine for today, says Christine Elliott, spokesperson for the Northwest Power Pool that monitors power in that region.
But observers say an unseasonably cold weather system is headed for the Pacific Northwest next week that could affect that region�s demand for power and necessarily its ability to export. In short, California market observers don�t expect the tight supply problem to be over quickly. Further complicating the Western markets, is the forced outage of a 430 Mw power plant in Hunter, Utah. That plant will be out at least 4 to 6 months for extensive repairs, said ScottishPower, the owner of the plant. That plant exports power to Western markets and California. That could factor into future import problems if winter demand increases in other Western regions.
California has 10,000 Mw down in planned maintenance outages and forced outages, says Jesus Arrendondo, spokesman for the California Power Exchange. The tight supply and anticipated cold weather is impacting the power markets. For the first time ever, bidders bid $249/ Mw-hr into the California Power Exchange�s day ahead market for every hour of the day, he says.
�That shows how tight the supply is even in off peak,� he says.
That is just inside the federally mandated price cap of $250/ Mw-hr. Suppliers know that they can get a higher price outside of California and didn�t want to test the possibilities of a Federal Energy Regulatory Commission review of their prices if they were above the $250 cap, suggests Arrendondo. Part of the recent FERC proposed order on California�s wholesale power markets was the cap and review of any bids over the cap.
