August 1, 2006
US power grids say have enough power to weather heat wave
By Scott DiSavino
NEW YORK (Reuters) - As people cranked up their air
conditioners to escape a blistering heat wave for another day
on Tuesday, power grid operators in the U.S. Northeast said the
supply of generation was enough to meet the forecast record
institute rolling blackouts, which are aimed at preventing
uncontrolled outages, due to any lack of generating capacity.
However, in some regions power distribution cables could
fail, like those which recently left 25,000 Con Edison
customers in New York without power for as long as week.
When this heat wave began in California, the power
transmission grid and generators experienced no problems. But
the heavy demand strained some power lines in the state,
leaving two million customers in the dark from just a few
minutes to a few hours to up to a few days.
Meteorologists forecast high temperatures would near 100
degrees Fahrenheit in Detroit, St. Louis and Chicago on Tuesday
and would top 100 degrees in New York, Philadelphia and
Washington on Tuesday and Wednesday.
PJM, the nation's biggest grid operator, which serves over
51 million people in the Mid-Atlantic and Midwest states,
forecast demand Tuesday would reach 148,275 MW, breaking the
record of 139,746 MW set on July 17.
That would surpass last year's record of 133,763 MW by
almost 11 percent.
One megawatt powers about 800 homes under normal
conditions. During a heat wave, however, a megawatt powers
"We have already asked customers to conserve energy Tuesday
where possible. At this time, we do not see the need to take
any other steps to shed demand," said a spokeswoman for PJM
which is headquartered in Valley Forge, Pennsylvania.
"We have a cushion of reserve power and do not expect to
have any problem meeting the forecast demand. Of course, if
anything changes - we lose a big power plant or transmission
line - we can take steps at that time to maintain reliability,"
In addition to calling on customers to conserve power, grid
operators usually notify generators and transmission owners to
delay all nonessential maintenance and keep extra crews in the
field to deal with unexpected emergencies.
And the grid operators and utilities can call on commercial
and industrial customers, who volunteered to cut power during
emergencies in exchange for lower utility rates, to reduce
OTHER RECORDS COULD FALL
The Midwest Independent System Operator, which serves 36
million people in 15 states and the Canadian province of
Manitoba, took some steps to shed demand on Monday and met a
new record peak usage with no major customer outages.
Customers in the Midwest ISO used 136,520 MW of electricity
on Monday, up 2.9 percent from the previous record of 132,658
MW set on July 17. That also broke last year's record of
131,434 MW by almost 4 percent.
The Midwest ISO forecast usage on Tuesday would be close to
the peak on Monday.
As the heat wave moves from the Midwest into the Northeast,
the grid operators in New York and Ontario also forecast record
usage on Tuesday and possibly Wednesday.
The New York Independent System Operator, serving about 20
million New Yorkers, forecast usage Tuesday would reach 33,500
MW, besting the record of 32,624 MW set on July 17. That would
break last year's record of 32,075 MW by about 4 percent.
The Independent Electricity System Operator in Ontario,
serving more than 11 million people in the province, forecast
demand Tuesday would reach 26,925 MW, breaking last year's
record of 26,160 MW set on July 13 by 3 percent.
ISO New England, serving more than 14 million people in the
six New England states, does not expect usage to reach record
levels until Wednesday.
New England forecast demand Wednesday would reach 27,700
MW, breaking the record of 27,395 MW set on July 18. That would
surpass last year's record of 26,885 MW by 3 percent.
Meteorologists forecast the heat wave would break on
Tuesday night in the Midwest and Wednesday night in the
Mid-Atlantic and Northeast as a cold front moves across the
continent from west to east, pushing the hot weather into the
(Additional reporting by Bernie Woodall in Los Angeles)