By the OGJ Online Staff
HOUSTON, May 8 -- With temperatures hitting record highs, California braced for a second day of possible rolling blackouts Tuesday.
Jim McIntosh, director of operations for the California Independent System Operator, warned blackouts are "probable" later in the day during a Tuesday morning conference call. "Demand is trending at 1000 Mw over where we were yesterday at this time," he said.
Earlier in the day, the ISO issued a Stage 1 emergency indicating reserves were below 7%. McIntosh said the ISO expected to issue a Stage 2 emergency about 1 p.m. PST and shortly after may call a Stage 3 alert, signaling reserves are below 1.5%, as demand rises. Low supplies continue to be the major problem, McIntosh said.
The heat spell, including a record 93° in San Francisco, has caused a surge in air conditioning, McIntosh said. A total of 12,088 Mw worth of generation remains unavailable with power plants off line for maintenance and plant malfunctions.
Four nuclear units are off line in the western US for refueling or repairs. In addition, McIntosh said an additional 2,000 Mw of generation from the state's qualifying facilities (QFs) is unavailable. Peak demand on the transmission system is expected to reach 34,469 Mw about 4 p.m. Tuesday.
More than 88,000 customers were without power for about an hour late Monday afternoon, after McIntosh said he believed the ISO would be able to get through the day without having to ask utilities to cut firm load.
Tuesday he said 900 Mw of interruptible load came back on line Monday after a 6 hr outage and load did not drop as he anticipated. McIntosh said there will be pressure to extend to 8 hr the required time for interruptible load customers to remain off line.
Pacific Gas & Electric Co. said about 54,000 customers were part of rolling block outages that began at 4:45 p.m. and ended at about 6:00 p.m. The utility has 14 outage blocks that each serve about 200,000 customers. About 36,000 Southern California Edison Co. also lost power.
Since January, the ISO has ordered blackouts Jan. 17-18 and Mar. 19-20.