California ISO orders load cut

With major plants off-line and temperatures at record highs Wednesday, the California Independent System Operator (California ISO), Folsom, ordered Pacific Gas & Electric Co. to initiate its local nonfirm interruptible load program from noon until 6 p.m.

br>With major plants off-line and temperatures at record highs Wednesday, the California Independent System Operator (California ISO), Folsom, ordered Pacific Gas & Electric Co. to initiate its local nonfirm interruptible load program from noon until 6 p.m.

PG&E Co.'s nonfirm interruptible load program involves several large customers who benefit from reduced energy bills in exchange for agreeing to curtail energy use when the need arises. In the San Francisco Bay area, the program amounts to 200 Mw, according to the ISO.

The program was triggered in response to continuing hot temperatures in northern California, particularly in the San Francisco Bay area, that are breaking 35-year weather records. Additionally, key generating units that serve the local load in the area are unavailable today. The California ISO said the order is intended to prevent large-scale disruptions of the power supply system while demand is high.

About 75 bay area customers participate in the nonfirm interruptible program. In addition to asking nonfirm customers to curtail use, PG&E has also asked customers with loads of more than 500 Mw to dim lights, adjust air conditioners, and turn off unnecessary office equipment. Similarly, residential customers have been asked to reduce demand on the system.

The state-chartered California ISO manages the flow of electricity along the long-distance, high-voltage power lines that make up the bulk of California's transmission system. The not-for-profit corporation assumed the responsibility in March 1998 when California opened its energy markets to competition and mandated investor-owned utilities turn their private transmission power lines over to the California ISO's open-market power grid.

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