New England rooftop solar cut heat wave power costs by $130 million, and at times beat nuclear

As temperatures surged in early July, solar panels on New England rooftops were supporting more than the buildings beneath them.

While homes and businesses used that power locally, the systems also took some of the burden off the regional grid as air-conditioning demand climbed.

Analysis connected rooftop solar to at least $130 million in reduced wholesale energy costs for electric customers during the weeklong hot spell.

Jamie Dickerson of the Acadia Center, who oversees climate and clean energy programs, said the savings resulted from rooftop systems reducing the amount of power the regional grid had to provide.

The effect was strongest during the hottest hours of the day. At certain points, the Acadia Center found, rooftop solar was meeting about 25% of the region’s total electric demand.

“It’s distributed solar, it is close to where the load is, you know the actual electricity consumption, that means that it effectively reduces the peak demand that is seen on the regional grid,” Dickerson said.

Solar’s summer payoff isn’t limited to New England. During a Level 1 grid emergency two summers ago, the same regional grid operator leaned on the same kind of relief as demand spiked with the heat.

Dickerson said the biggest cost effects showed up during the most intense heat of the week.

“Basically, we saw between 28% and 43% of daily costs were avoided by the distributed solar in the region,” Dickerson said. “Between 2 p.m. and 7 p.m. on that hottest day of July 2, the distributed solar actually contributed more to the fuel mix than the region’s nuclear fleet.”

To read the full article from the Cool Down, click here.