The U.S. Midwest power grid operator issued an emergency warning for the FirstEnergy service territory in Ohio due to unplanned generation outages and heavy power usage for air conditioning during a heat wave blanketing the eastern half of the nation.
Meteorologists forecast temperatures would reach the low 90s Fahrenheit on Monday and Tuesday in Cleveland before dropping to normal levels in the 70s on Wednesday.
The Midwest ISO, which operates the Midwest grid, said the problem was primarily in the Cleveland area.
A spokesman for FirstEnergy said it was preparing all of its available power plants for service as per the ISO request.
He could not say which facilities were out of service for unplanned work due to competitive reasons.
Electricity traders noted the ongoing outage at the company's 1,235-megawatt Perry nuclear plant located about 35 miles northeast of Cleveland, which could meet the power needs of about a million homes, was certainly part of the problem.
The company shut Perry on June 29 to replace a 20-ton motor in the reactor recirculation system.
To reduce the stress on the system, FirstEnergy said it reduced its own power usage and told those primarily industrial customers that signed interruptible contracts to cut their usage, in addition to asking all customers to conserve energy voluntarily, the spokesman said.
The power company estimated it could save about 500 MW to 600 MW by cutting power to the interruptibles and its own facilities.
Interruptible customers buy power at a discount for agreeing to reduce usage when needed.
The spokesman said that none of its customers were without electricity due to the heat. Real-time prices in the FirstEnergy hub meanwhile jumped to over $500 per megawatt hour several times on Monday. Prices in the hub usually trade in the $60s and $70s.
FirstEnergy, of Akron, Ohio, owns and operates nearly 14,000 MW of generating capacity, markets energy commodities, and transmits and distributes electricity to about 4.5 million customers in Ohio, Pennsylvania and New Jersey.
The Midwest ISO operates the power grid in Illinois, Indiana, Iowa, Kentucky, Michigan, Minnesota, Missouri, Montana, Nebraska, North Dakota, Ohio, Pennsylvania, South Dakota, Virginia, Wisconsin and Manitoba, and administers the wholesale electric market with a generating capacity of more than 132,000 megawatts.