Four years ago the lights went out across California as power demands outstripped supply. Electricity prices went through the roof. Later we learned that the culprits were several generating companies -- including Enron -- that withheld generating capacity to drive up prices.

Something reminiscent of that may be happening now in the Washington area: On Aug. 24 the Potomac River Generating Station in Alexandria was shut down voluntarily by its owner. Without this 482-megawatt plant, the power supply in the District and adjacent Maryland suburbs is dangerously close to the edge. A late heat wave could create rolling blackouts.

The now-idle Potomac River plant is owned by Mirant Corp., one of the five generating companies that allegedly manipulated California's energy markets in 2000 and 2001. After being accused of curtailing output at its power plants in the San Francisco Bay area, Mirant agreed to pay almost a half-billion dollars to aggrieved California consumers and utilities. Despite recent documentation of potential emissions violations at the Potomac River plant, Virginia environmental regulators did not order Mirant to close the Alexandria facility. But instead of pursuing a cleanup plan with the Commonwealth, Mirant chose to close the plant with barely 48 hours' notice.

While Mirant said that the closure is about "protection of public health" (per a full-page ad in The Post), such altruism rings a bit hollow. Mirant is aware of the strategic value of withholding capacity, and it has asked for a federal preemption of Virginia's air pollution requirements if it is ordered to restart the plant.

Mirant, some may recall, filed for bankruptcy court protection two years ago and is engaged in a bitter financial struggle with Pepco. Through its bankruptcy filing, Mirant seeks to get out from under its money-losing power supply contracts while keeping the four lucrative power plants it bought from Pepco.

In shutting down the Potomac River plant, Mirant appears to be violating federally approved operating procedures requiring 90 days' notice before deactivating a generator. Such rules are meant to prevent conduct that could potentially bring down the grid or send electricity prices soaring.

Rather than put D.C. consumers -- including critical federal facilities -- at risk of California-style blackouts, I joined my colleagues on the D.C. Public Service Commission last month in asking the Federal Energy Regulatory Commission (FERC) for an emergency order to restart the Potomac River plant while searching for a long-term solution to pollution issues. The D.C. commission's petition -- which is supported by public officials, utilities, regulators and the region's grid manager -- is pending at FERC and the Department of Energy.

As a former environmental regulator, I take seriously the pollution concerns raised by Virginia officials and Alexandria residents. To protect our air quality, the region urgently needs to explore alternatives to the Potomac River plant as it is configured.

But that doesn't justify Mirant putting citizens and the federal government at increased risk of power outages. The future of the Potomac River plant must be determined through an orderly process that keeps the grid intact. Otherwise, we might suddenly find ourselves in the dark.

-- Richard E. Morgan

is a commissioner at the Public

Service Commission of

the District of Columbia.