Heat keeps power tight on East Coast

With the continuing heat wave on the East Coast, grid system operators called for conservation and warned of extremely tight power conditions continuing for several more days.

New York, New England, and the PJM Interconnection area are suffering from hot humid weather causing these grid operators to issue calls for voluntary conservation.

The New York Independent System Operator (NYISO) upped its peak load forecast for Tuesday to 30,995 Mw from yesterday’s forecast of 30,558 Mw. In either case, the peak would set an all time record for the state, said Carol Murphy, spokeswoman for NYISO.

“The cumulative effect of heat in the city really drives the load up,” said Murphy. “Thursday will be even more interesting.” Murphy said hot temperatures are expected to hover over the East for several more days.

“Our biggest concern is Long Island,” she said. “Long Island will be very tight because it is difficult to get more power in there.”

Inadequate transmission capacity to the island means extra power shipped into the state won’t help the situation. But the ISO maintains an 18% reserve margin required by law. It is also exporting about 2,000 Mw of power to neighboring areas that are worse off, she said.

“That power is recallable, if we need it,” Murphy said.

In neighboring New England, the ISO New England had counted on 427 Mw of scheduled power contracts from New York. But the NYISO has already cut back its exports to New England to 300 Mw.

Because of the tight conditions, the ISO New England has requested load serving entities acquire additional power of 300-400 Mw for the peak hours today, said Ellen Foley, spokeswoman for ISO New England.

The ISO issued a type of emergency allowing very short-term power purchases not otherwise allowed without penalties. The $1,000/Mw-hr bid cap is not in place for this power, she said.

The New England area is bumping up against the maximum amount of power it can import from outside the region. Hydro Quebec can transfer at most 2,225 Mw of power into New England. There are scheduled contracts for 1,987 Mw. Imports from New Brunswick are at the maximum of 700 Mw.

Despite the ability of the transmission system to accommodate 1,600 Mw of exports, New York can’t spare more than 300 Mw. ISO New England has 558 Mw of surplus capacity beyond the required reserve. Only if that surplus goes to zero will further steps such as voluntary load reduction take place, Foley explained.

PJM issued and then canceled transmission line overload warnings today for western Pennsylvania. GPU Energy a unit of GPU Inc., Morristown, NJ, called for voluntary reductions and received 15 Mw of load reduction from its interruptible load customers, said spokesman Scott Surgeoner. He said GPU doesn’t expect any problems meeting today’s demand.

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