Power reserves run low in California

FOLSOM, Calif. (CNN) -- California power officials urged residents to conserve electricity Tuesday as the state flirted with rolling blackouts a day ahead of the Fourth of July holiday.

California's power grid controller declared a Stage Two emergency and warned utilities in early afternoon that rolling blackouts were likely -- a warning that was later rescinded.

Kristina Werst, a spokeswoman for the California Independent System Operator, said the power grid was able to secure enough power to avoid blackouts for the day.

IN DEPTH California's Power Crisis   The Energy Crunch

"It's going to be tight," she said. "Conservation is critical."

A statement from ISO said the state's appetite for power is 1,000 megawatts over forecast due to high humidity and temperatures.

MESSAGE BOARD The Energy Crisis

A Stage Two emergency is declared when operating reserves dip below five percent. At this level, large commercial customers who have signed on to a special program will curtail their power demand voluntarily. If the operating reserve drops to less than one-and-a-half percent, a Stage Three power emergency is declared and rolling blackouts may occur.