Plant loss prompts California ISO warning

With a 1,300 Mw unexpectedly off line in the Northwest curtailing imports into California, the California Independent System Operator (ISO) declared a Stage 1 electrical emergency Wednesday. The ISO called for immediate conservation measures and said it is working to secure additional power in an effort to avoid initiating a Stage 2 emergency.


With a 1,300 Mw unexpectedly off line in the Northwest curtailing imports into California, the California Independent System Operator (ISO) declared a Stage 1 electrical emergency Wednesday.

The ISO called for immediate conservation measures and said it is working to secure additional power in an effort to avoid initiating a Stage 2 emergency.

Californians were already hunkered down for another day of hot weather and darkened offices Wednesday as the California Independent System Operator earlier issued a warning and solicited supplemental bids of up to 4,000 Mw�its highest of the week�to boost power supplies.

Early in the day, the ISO was projecting peak loads of 45,065 Mw Wednesday, exceeding by 65 Mw the amount of peak power connected to the ISO-controlled grid. The agency later reduced projected peak demand for the day to 42,178 Mw.

Temperatures were projected to reach the triple digits in the Valley area and the high 90� F. in the San Francisco Bay. area. After narrowly averting rolling blackouts Monday, the ISO made it through Tuesday without having to issue a Stage 2 alert, indicating reserves have fallen below 5% and activation of interruptible supply contracts.

If power reserves drop below 1.5%, the ISO moves to Stage 3, directing utilities to "drop load," necessitating controlled, involuntary rolling, or rotating, outages for groups of customers across their service areas until sufficient reserve levels are achieved.

Energy consumption nearly exceeded energy availability, challenging the power grid, Monday, ISO officials said. The agency, which manages most of the California grid, got emergency electricity supplies from the federal Bonneville Power Administration and the Western Area Power Administration to help supply Monday's peak power demand and avoid a Stage 3 emergency. It also directed state utilities to drop all interruptible load customers.

More in Pipelines & Transportation