Demand for electricity in New England is about to start rising for the first time in two decades, causing potential problems in winter when solar power is weak, but for the time being we’re in good shape.

That’s the opinion from ISO-New England, the organization that oversees the six-state power grid, as part of its seasonal and annual forecasting.

For the upcoming summer, ISO-NE said the region has more than enough power plants – gas-fired, nuclear, hydropower, solar and wind – to meet the region’s expected needs. 

A contributing factor is the growing importance of rooftop solar, officially known as behind-the-meter, which reduces demand from power plants by producing electricity locally. The amount of rooftop solar has been steadily increasing in New England and at times in April it was generating five times as much electricity as the Seabrook Station nuclear plant. 

Rooftop solar cutting into demand is one reason the total amount of electricity generated by power plants in New England has fallen steadily for 20 years. ISO-NE says this “net energy use” has gone from 136,425 gigawatt-hours during 2005 to 116,813 in 2024 – a decline of almost 15%. 

Other programs such as demand response, when customers are paid to reduce their power draw during heavy-usage days, have also contributed to the drop in demand.

But that historic pattern is ending, ISO-NE says. It expects a small uptick in usage this year followed by steady increases that will raise demand to 130,000 gigawatt-hours within a decade. 

Increased demand will be caused by more air conditioning as the climate heats up, more use of electric vehicles, induction stoves and heat pumps as part of efforts to reduce greenhouse gas emissions, and growth in data centers and other large users of power.

Meeting that need will be most difficult in winter, when solar power declines sharply. ISO-NE says that in the next few years, New England will shift from its longtime pattern of “summer peaking” – meaning power plants need to produce the most electricity at one time during mid-summer days – to “winter peaking.”

This is a potential problem because New England’s electrical system is heavily dependent on natural gas as a fuel. In winter much of that gas goes to heat homes, making it harder and more expensive for gas-fired plants to keep running.

For this summer, ISO-NE predicts demand to reach 24,803 megawatts (MW) under normal weather conditions, with one megawatt being the electricity used by between 700 and 1,000 homes. Demand could rise to 25,886 MW during extended heat waves but the region has plants that can generate 29,000 MW at a time, more than the all-time highest demand New England has seen.

ISO-NE cautions that extreme weather events such as a storm that knocks out a power plant could cause brownouts or other problems.

David Brooks can be reached at dbrooks@cmonitor.com