The New England power grid was put on “power caution” status Friday afternoon as the region baked for a fifth day.
The Independent System Operator that runs the grid – ISO New England – instituted its procedure for a capacity deficiency around noon as power demand zoomed past 27,000 megawatts toward a predicted high of 27,850 megawatts. Not a record, but close enough for discomfort, and the day will likely close out as at least the fourth highest power demand on record.
A spokeswoman for ISO New England said the system operator dipped into the power reserve it carries for such emergencies, and it instituted a so-called “demand response,” which calls on certain companies to curtail their power use. She said by about 1 p.m., the effects of those moves were apparent as the power demand began to flatten out.
ISO also began making preparations for power imports from neighboring regions.
The old record for power demand in New England came on Aug. 2, 2006, when demand reached 28,130 megawatts. With temperatures expected to back off and weekend electricity demands significantly lower than weekday ones, ISO New England is predicting diminished power needs tomorrow. But with a prediction of 24,200 megawatts, Saturday could actually set an all-time record for weekend power demand.
The region’s four nuclear plants remain operational after scares at the Pilgrim Nuclear Power Station in Plymouth, Mass., earlier in the week. The seawater it uses to cool the plant exceeded its allowable level for a time Tuesday and again on Wednesday. While the situation forced the plant to reduce capacity by 15 percent Wednesday, it did not have to shut down on either day.
The cooling water at the Millstone Nuclear Power Station in Waterford, averaged “on the high side of 70 degrees” Friday afternoon, according to a spokesman, still several degrees from its limit. Last summer one of its units shut down for 12 days because intake water temperature exceeded the 75-degree limit.