In a summer that has brought little but sweat for Commonwealth Edison Co., the state’s largest utility managed with few problems Tuesday to meet near-record demand from its customers amid soaring heat and humidity.
At midafternoon, ComEd supplied 18,820 megawatts of power to its 3.4 million customers, or 94 percent of the utility’s 20,000 megawatts of available electricity. Tuesday’s peak demand still fell short of ComEd’s record of 19,212 megawatts used on Aug. 10, 1995, and this summer’s record of 19,012 megawatts on June 25.
But ComEd spokesman Don Kirchoffner said that, though the company ended the day $30 million poorer after having to buy 4,000 megawatts generated by other utilities, Tuesday generally was no problem.
“All over the country, utilities were appealing to their customers to cut back, yet we weren’t even close to the dreaded involuntary curtailments, or rolling blackouts,” he said. “But we didn’t get cocky. We knew that demand was going to be very high, the heat was very high and the humidity was very high.”
The temperature hit 94 degrees at O’Hare International Airport, just short of the 95 degrees recorded on June 25 and 27. Tuesday’s 103-degree heat index, a measure of heat and humidity, also fell just short of this summer’s high of 106 degrees, reached on June 27.
Helping hold down demand for electricity was a line of strong thunderstorms that swept through parts of northeastern Illinois on Tuesday afternoon.
Near the Wisconsin-Illinois border, the storms packed such intense winds that they knocked over seven semi-trailer trucks traveling along Interstate Highway 94. The storms also knocked out power to more than 17,000 ComEd customers.
Downtown along the Chicago River, tourists and locals armed themselves, many unsuccessfully, as they tried to beat the heat.
“It’s an oven out here,” said Hakyung Kim, a 27-year-old from the North Side whose double-scoop ice cream cone practically melted to soup moments after she left a Baskin-Robbins store. “The cone’s not doing much good.”
Though ComEd was able to meet demand for electricity without cutting service to any of its residential customers, it did pull the plug on six large industrial and commercial companies to gain an extra 340 megawatts. In exchange for discounted electricity rates, the companies agree to have their service interrupted in times of peak demand.
ComEd also said early weather forecasts predicting temperatures in the mid-90s helped give the utility plenty of time to buy extra power on the open market, enough to compensate for one of its coal-fired plants that remains shut down after a fire last week.
The Powerton plant, in Downstate Pekin, normally generates 820 megawatts of electricity, which Kirchoffner called significant on such a hot day. Powerton is expected to be back in service July 29.
The violent but brief thunderstorm that struck shortly after 3 p.m. whipped through communities from as far north as Waukegan and Rockford to as far south as Pontiac.
High winds and fallen tree limbs from the storm knocked out power for 13,197 residents in the north suburbs, primarily in McHenry and Lake Counties; 3,805 in the Rock River area; 518 in Chicago; and 323 in the south suburbs.
Crews were working Tuesday night on scattered weather-related outages that affected about 3,500 customers in the Yorkville and Woodridge areas.
In addition, about 1,900 customers on Chicago’s North Side lost power about 8:45 p.m., but not because of the weather. A ComEd spokesman said the outage in the area bordered by Wellington Avenue, Addison Street, Sheridan Road and Sheffield Avenue near Belmont Avenue and Halsted Street was caused by a problem with an underground cable.
“The normal crews of about 200 will be out working to restore power,” said Kirchoffner.The utility expects to have power restored to most customers by Wednesday morning.
The weather created a traffic nightmare in Kenosha County, Wis., just north of the Illinois border, after the seven trucks were blown over by high winds. Traffic along I-94 between Wisconsin Highways 142 and 11 had to be rerouted for three hours. Kenosha County sheriff’s police reported no serious injuries.
Chicago Mayor Richard Daley expressed guarded satisfaction that ComEd had arranged to buy enough extra electricity from other power companies and brokers to make it through the current hot spell.
Daley said he is “a little more confident” in the company’s ability to supply what is needed, but “not 100 percent.”
Still of concern to city officials, only a month after ComEd came perilously close to not meeting the area’s power demands, are the utility’s plans to impose temporary blackouts should it again find itself in a power crisis.
City Environment Commissioner Henry Henderson said Tuesday that he expects by week’s end to have a list of 1,000 critical city buildings and street intersections and how they fall within ComEd’s rolling blackout plan.
The buildings include hospitals, schools, police and fire stations, city cooling centers, pumping stations and elderly housing.
ComEd technicians have been of little help in matching street addresses to circuits that would be shut down under each of the company’s 26 blackout scenarios, Henderson said, and the city has assigned 25 computer specialists to examine the information.
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