Updates on hot weather operations

June 21, 2024 – 9:30 a.m.

New England’s power grid remains reliable coming out of the highest demand of this week’s heat wave.

Consumer demand for electricity peaked Thursday evening at 23,324 megawatts (MW), in line with forecasts, and ISO New England’s system operators did not need to take any additional actions to maintain system reliability. At 10 p.m. Thursday, the ISO lifted the Abnormal Conditions Alert, which had been issued on Tuesday evening due to the hot weather.

With temperatures falling across much of the region, the ISO projects demand to reach 20,000 MW on Friday, a 14% decrease over the previous day. While the ISO projects adequate supplies of electricity, system operators and forecasters will continue monitoring conditions, and have tools at their disposal to handle unexpected conditions. 

Barring any unexpected developments, this will be the final system conditions update of the heat wave.

June 20, 2024 – 9:30 a.m.

New England’s power grid continues reliable operations entering the third day of a region-wide heat wave.

Consumer demand for electricity peaked Wednesday evening at 22,803 megawatts (MW), in line with forecasts. The region’s generation fleet performed well throughout the day, and ISO system operators did not need to take any additional actions to maintain system reliability on Wednesday.

ISO New England projects demand to reach 23,900 MW Thursday evening, which would mark the highest level of the season. The ISO anticipates having the necessary resources to meet consumer demand and required reserves. System operators have tools at their disposal if unexpected conditions materialize.

A region-wide abnormal conditions alert remains in effect due to the potential for the hot weather to impact system operations.

Demand on the regional system is expected to ease on Friday as the heat wave breaks in certain portions of New England, including the Greater Boston area.

June 19, 2024 – 8 a.m.

New England’s power system remains reliable despite widespread hot weather across the region.

On Tuesday evening, ISO New England declared a Power Caution after unexpected generation outages left the region short of meeting its operating reserve requirements. The timing of the outages prevented additional resources from coming online in time for the evening peak.

During a Power Caution, ISO system operators are able to utilize reserve resources to balance the power system.

The region had adequate supplies of electricity to meet consumer demand, and the power system remained reliable at all times. The ISO lifted the Power Caution at 10 p.m. as consumer demand declined.

An abnormal conditions alert was also issued Tuesday evening and remains in effect due to the hot weather.

Electricity demand during the heat wave is expected to peak Thursday evening.

June 17, 2024 – 3:30 p.m.

ISO New England anticipates normal system operations this week, despite forecasts calling for hot temperatures across the region Tuesday through Sunday.

In New England, consumer demand for electricity is highest during the summer because of air conditioning use. “One of the biggest drivers for our demand is what the temperature is,” Mike Fontaine, ISO‑NE operations forecasting supervisor, said in a recent ISO Minute. “A one degree change in temperature can impact the load, or demand, in New England significantly.”

As of Monday afternoon, the ISO expects peak demand to reach 23,750 megawatts (MW) on Thursday, June 20. Though this would represent the highest demand this year, it is within the expected range forecasted for the summer season. New England’s all-time record for electricity demand was set on Aug. 2, 2006, when demand reached 28,130 MW after a prolonged heat wave.

While the ISO projects adequate supplies of electricity in the coming days, system operators and forecasters are continuously monitoring conditions. If needed, the ISO’s highly-trained operators will follow well-established operating procedures to balance supply and demand on the regional power system.

Though the ISO is not anticipating to call for public conservation, residents interested in reducing their energy use can:

• Install window coverings to prevent heat gain through your windows during the day.
• Limit using your washer, dryer, and dishwasher.
• Unplug unused electronics.
• Turn off unnecessary lights.
• Clean air intake vents and replace the filter for air conditioners for maximum energy affordability.

Visit the U.S. Department of Energy’s website for more information and tips.