Daytime Power Demand Dipped Below Night For A Moment — And New England Solar Advocates Are Cheering

Jun 4, 2018

Solar power’s emergence as an important feature of New England’s energy landscape just hit an important milestone.

Normally the amount power drawn from the regional grid is lowest at night. But one sunny day this spring, residential solar arrays flipped that pattern around — and the phenomenon will likely become more frequent in New England.

It happened on April 21.

“It was a Saturday, it was the weekend and we had relatively mild weather, so there was light consumer demand on the electricity system. And it was a particularly sunny day,” says Anne George, a spokeswoman for ISO-New England, the group that runs the region’s bulk transmission grid. “We saw record high output from solar installations in the region, which led to the first-time ever in New England seeing load and demand of the electricity system at a lower level in the middle of the day as opposed to overnight when everybody’s sleeping. That was a first for us.”

For solar power advocates in New England, it’s a moment to savor.

“You are seeing the promise of a distributed, renewable electric grid in the charts and graphs coming from ISO-New England,” says Steve Hinchman, general counsel for a regional solar company called ReVision Energy, standing by the inverter system of a 5,000-panel solar array the company recently installed at a growing business park in Brunswick. “It shows that renewables deployed at the bottom of the grid can offset demand and lower our overall need for electricity, because we are generating the power that we need where we use it, without having to have the grid deliver it.”

Solar power’s ability to drive grid-scale reductions in demand was expected: The capacity of off-the-grid solar installations in New England — mostly rooftop solar panels — has grown almost tenfold since 2012, to 2,400 megawatts. Roughly speaking, that’s enough to power almost 2 million homes — when the sun is shining.

“The longtime rhetorical flourish that environmentalists have liked to use about how fast the electricity grid is changing turns out to actually be true now,” says Jeremy Elmer, a Rhode Island-based attorney with the Conservation Law Foundation.

Elmer says that as behind-the-meter solar lowers demand on the grid, that can avert the need for costly new long-distance transmission lines and upgrades. And when daytime demand drops, he adds, that can lower overall electricity prices in real-time markets.

And most importantly, from the environmentalists’ perspective, it lowers the amount of carbon dioxide pollution created in electricity production.

“It’s paying off in terms of lower consumer costs, it’s paying off in terms of lower carbon emissions. It’s paying off in terms of real tangible change on the electricity grid,” Elmer says.

Policymakers around New England continue to debate whether all electricity users should help pay for poles, wires and other distribution services that rooftop solar power users need from time to time. But even with that issue in flux, it’s expected that solar capacity will almost triple over the next several years.

That will create some challenges, with grid managers deciding what kind of quick-response power plants might be needed — including fossil-fueled facilities — to manage the rapid surge in demand on the grid that appears when the sun goes down.