High heat drains electric power

September 17, 1991|By Frank D. Roylance | Frank D. Roylance,Evening Sun Staff

The late-summer heat wave that continued to smash record in Baltimore and Washington today has caught the region's utility managers with their plants down.

Routine plant shutdowns, timed for the slack periods between the demand peaks of summer and winter, left the power grid with barely enough reserve generating power to cope with record-breaking heat and humidity, officials said.

"We've just got everything loaded to the hilt," Charles B. Woodward said as demand peaked yesterday. Woodward is operations manager at the Pennsylvania, New Jersey, Maryland Interconnection, which manages the electrical power grid serving 21 million people from New York to Washington.

Today, with temperatures falling in the Midwest, the power grid has been able to import more electricity from Indiana, Ohio and western Pennsylvania. "We're in better shape," he said.

Although the demand for power in the PJM grid was running 1,000 megawatts higher than yesterday, "we've got a couple thousand more available to us."

No emergency cutbacks should be needed today, he said, "unless we have a large unit trip off line unexpectedly."

Yesterday, the supply of power was so tight that the Baltimore Gas and Electric Co. was forced to ask key industrial users to switch to alternate fuels. And 120,000 residential customers had their air conditioners switched off briefly by remote control.

Despite the improved power supply picture today, BG&E reissued yesterday's appeal to 1 million residential customers to raise their thermostats to 80 degrees, postpone the laundry until after 8 p.m., and cook outdoors on the grill if possible.

The National Weather Service said today's 19-year-old temperature records were kayoed before 11:30 a.m., as the mercury pushed past 92 degrees at the airport and 93 degrees downtown.

By 1 p.m., it was 96 degrees downtown, up from a 6 a.m. low of 81 degrees. It was 95 at the airport.

Schools in Anne Arundel, Baltimore, Carroll and Harford counties, which toughed out yesterday's heat, threw in the towel today and dismissed students one to three hours early.

So did those in Talbot, Allegany, Frederick, Caroline and St. Mary's counties. City schools closed at 12:30 p.m. for a second day. Howard County closed only its Gateway special education school, at noon.

The revised forecast for tomorrow calls for some relief, with temperatures in the upper 80s and continued high humidity.

Thunderstorms tomorrow afternoon and evening will precede the passage of a cool front early Thursday, said forecaster Bob Melrose.

The new Canadian air behind the front is expected to bring milder weather Thursday with highs near 80. By Friday, highs will barely reach 70, with overnight lows from the mid-40s in the colder suburbs, to the mid-50s the city.

But, for now, the Southern discomfort is at full strength, leaving the utilities scrambling to slake the region's thirst for electricity.

"The forecasted [demand for electricity] was nowhere near what we got," Woodward said last night. "I've never seen the load pick up from what we call the 'midnight valley' to the load we have now."

Normally the demand for power across the regional power grid would climb 40 to 60 percent over the course of the day, he said.

Yesterday, Woodward said, "it probably doubled. That's a very healthy amount of electricity to come up with."

Temperatures in Baltimore reached a record 98 degrees at Baltimore-Washington International Airport at 3:13 p.m. yesterday, breaking the 97-degree record set in 1970. The high downtown reached 95 degrees at 2:25 p.m., tying a 1970 record for the date there.

New record highs were also set in Philadelphia (94 degrees), at Washington's National Airport, (96) and at Dulles Airport in Virginia (97).

The demand for power from BG&E customers reached 5,135 megawatts at 5 p.m. yesterday. That broke the previous September record of 4,930 megawatts, set in 1989, said BG&E spokesman Art Slusark.

The all-time peak demand at BG&E was 5,910 megawatts, set on July 23 of this year.

Slusark said the utility easily met the record demand in July, partly because it had all its biggest generators in operation, including both 642-megawatt coal-fired generators at Brandon Shores in Anne Arundel County, and both nuclear generators at Calvert Cliffs.

But last Friday, Brandon Shores I, the older of the two units there, was shut down for four months so that its control panels can be replaced with updated equipment.

"It's a regional problem right now," Slusark said. "It's sort of the beginning of the time when plants start to go off-line for planned outages and upgrades."

Utilities try to schedule routine maintenance for off-peak months when the generating capacity probably won't be missed.

Several generating stations in Pennsylvania, New Jersey and New York are also shut down now for routine maintenance, including the Peach Bottom 3 nuclear station in Delta, Pa., which is being refueled, Slusark said. Several unscheduled shutdowns complicated the picture.

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