Californians were asked to institute conservation measures Wednesday, after the California grid operator declared a Stage 1 electric emergency and asked for supplemental bids on 3,000 Mw of power.
The California Independent System Operator (ISO), the nonprofit agency that manages 75% of California's transmission power grid and secures power supplies for most of the state's consumers, said the Stage 1 emergency, signifying reserves have fallen below 7%, would be in effect until 10 p.m. tonight.
Wednesday's demand is expected to peak at 32,730 Mw.
Late Tuesday the grid operator issued a Stage 2 alert and asked state utilities to activate voluntary load curtailment programs following the unexpected loss of generation in the southern part of the state. Southern California Edison (SCE), a unit of Edison International, said it was directed to reduce electrical load more than 1,400 Mw�enough power to serve 1.5 million homes.
To achieve the load reduction during Stage 2, SCE was required to activate its voluntary load curtailment program, under which large industrial, commercial, and agricultural customers have agreed to temporarily reduce power consumption in exchange for reduced rates.
The ISO said power reserves were already tight with 10,000 Mw offline due to planned and forced outages and a limited amount of imports available from the Northwest. A Stage 2 alert is declared when reserves dip below 5%.
In the event reserves fall below 1.5%, the ISO would declare a Stage 3 alert and begin involuntary curtailments, including the possibility of rolling blackouts.