California ISO issues power shortage alert

With temperatures expected to soar to more than 100� F. in California, the California Independent System Operator called for conservation measures Monday. California is heading into the summer under extremely tight electricity conditions, with the margin for reserve power projected to be less than 1%. Up to now, the California ISO has been counting on normal weather, conservation, and power imports to get through the summer with its slim reserve margin.


Kate Thomas
OGJ Online

With temperatures expected to soar to more than 100� F. in parts of California, the California Independent System Operator called for conservation measures Monday. The peak demand on the ISO-controlled grid is expected to climb to 40,500 Mw by late Monday afternoon. The record peak was 45,884 Mw on July 12, 1999.

The sudden state-wide heat wave is expected to continue with triple-digit temperatures for some portions of the state over the next few days, the ISO said. It urged Californians to watch their energy consumption, curtailing their use of electricity whenever possible.

The ISO manages the flow of electricity along long-distance, high-voltage power lines that make up the bulk of California's transmission system and is responsible for keeping the open-market power grid in California reliable, competitive, and accessible.

With inland highs expected to reach 102� F. and coastal temperatures in the 90s, air conditioners are expected to create a heavy demand for electricity. Up to now, the California ISO has been counting on normal weather, conservation, and power imports to get through the summer with its slim reserve margin.

Even with a normal summer, the system has only 100 Mw to spare to serve an expected peak load of 46,250 Mw. The amount of power that can be generated in California is 37,950 Mw. Officials expect "imports" into the state to be 8,400 Mw, for a total capacity of 46,350 Mw.

"There is no reserve margin in California," Dynegy Chief Operating Officer Steve Bergstrom said at the company's annual meeting in Houston earlier this month. A large diversified energy company, Dynegy is a power marketer and merchant power plant owner, selling gas and power in the California market.

California official claim up to 2,700 Mw of interruptible load is available from large industrial customers who will be asked to get off the system when demand begins to exceed supply. However, under a hot summer scenario, the forecast peak load of 48,940 Mw could outstrip available resources, the ISO said in a statement.

Power demand began growing in California at a time utilities were not investing in new generating capacity, the result of uncertainty over the outcome of restructuring of the electricity industry. The permitting process has also delayed construction of new facilities. Still, many observers believed there was enough reserve to get by until new merchant plants could be constructed, an assumption that will be tested this summer.

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