This is an excerpt from EERE Network News, a weekly electronic newsletter.

July 26, 2006

Record Power Demand Sweeps the United States

The United States has seven regional independent operators of electrical grids, stretching from California to New England, and every one of them experienced record power demand in late July. A press release from a group representing the seven regional grid operators notes that the peak power demands reached a level that was 0.9 percent to 4.5 percent higher than in 2005. According to the group, regional grid operators reported a new aggregated peak record of electricity usage of 483,233 megawatts during the extreme heat and high humidity, a full 7,500 megawatts above last year's peak. Despite the high electrical loads, the grid operators were able to maintain adequate reserve margins to avoid rolling blackouts. See the press release on the Midwest Independent System Operator Web site (PDF 98 KB). Download Adobe Reader.

The grid operator group may have been premature in its announcement, however, as the California Independent System Operator (ISO), which operates the California power grid, faced a tight supply situation in the last week of July. On July 24th, the California ISO declared a Stage Two emergency, which meant that peak power demand was within five percent of the grid's capacity. The emergency required load reductions from companies that have agreed to participate in a voluntary load reduction program. The heat had already caused sporadic power outages throughout California, including an outage that left 16,000 customers without power in Los Angeles. See the press releases from the California ISO and the Los Angeles Department of Power and Water.

Despite the threats from heat, as of July 25th, storms were to blame for the largest power outage in the United States. According to Ameren Corporation, more than a million customers lost power due to storms in Missouri and Illinois on July 21st, and by July 24th, 171,000 customers in St. Louis remained without power. All of which places a heavy responsibility on the North American Electric Reliability Council (NERC), an organization that develops electric reliability standards. On July 20th, the Federal Energy Regulatory Commission (FERC) named NERC as U.S. Electric Reliability Organization (ERO), giving NERC the legal authority to enforce its reliability standards. The change was authorized by the Energy Policy Act of 2005 and was triggered in part by the August 2003 blackout that affected 50 million people in the United States and Canada. See the Ameren press releases from July 21st and July 24th and the NERC press release (PDF 75 KB).

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