Dramatically illustrating the gap between California's demand for electricity and its generating capacity, the state on Wednesday ordered long-threatened mandatory rolling blackouts for the first time since California's energy crisis began last summer.

For weeks the California Independent System Operator, the Sacramento-based agency that manages the capacity and flow of the state's power lines, had staved off blackouts by cobbling together enough energy from municipal utilities and out-of-state suppliers. But when reserves dipped below 1.5% early Wednesday, Cal-ISO ordered utilities in northern California to reduce usage by 500 MW in 60-minute to 90-minute blackouts. By Wednesday evening Cal-ISO declared a temporary respite on outages, but warned that more are likely.

Wednesday's blackouts again pointed up the continuing inability of the state's power grid to meet the demand power generated by its growing economy and population. Cal-ISO estimated Wednesday's projected peak demand at 32,279 Mw, and although the California Energy Commission estimates the state's theoretical generating capacity at 53,000 Mw, that figure includes municipal-owned utilities and self-generation as well as investor-owned utilities, notes Susanne Garfield, a CEC spokesperson.

A more realistic estimate of the state's capacity is well under 50,000 Mw, Garfield says. Cal-ISO estimates that at least 11,000 Mw are currently off line because of planned or unplanned outages, and additional capacity is unavailable for a variety of reasons--stretching the state's reserves to the limit.

As California braced for more blackouts, the state's two largest investor-owned utilities veered closer to bankruptcy, and state officials continued the search for solutions to the crisis. Southern California Edison and Pacific Gas & Electric are caught between rising wholesale energy prices and fixed retail prices. This week the legislature is considering a controversial proposal to authorize the state to buy electricity and sell it to consumers.