As rooftop solar gets hammered, virtual power plants offer a way forward

But the fact remains that solar panels — and the lithium-ion batteries that increasingly accompany them — remain the cheapest and most easily deployable technologies available to serve the ever-hungry U.S. power grid.

Sachu Constantine, executive director of nonprofit advocacy group Vote Solar, thinks that the rooftop solar and battery industries can survive and even thrive if they focus their efforts on becoming ​“virtual power plants.”

Hundreds of thousands of battery-equipped, solar-clad homes across the country are already storing their renewable energy when it’s cheap and abundant and then returning it to the grid when electricity demand peaks and utilities face grid strains and high costs — in essence, acting as ​“peaker” power plants.

In places like Puerto Rico and New England, these VPPs have demonstrated their worth in recent months, preventing blackouts and lowering costs for consumers, and the approach could be scaled up dramatically. ​“If we do that, despite the One Big Beautiful Bill, despite the headwinds to the market, there is space for these technologies,” Constantine said.

Right now, there aren’t many other options for meeting soaring energy demand, he added. The megabill signed by President Donald Trump this month undermines the economics of the utility-scale solar and battery installations that make up the vast majority of new energy being added to the grid. And despite the Trump administration’s push for fossil fuels, gas-fired power plants can’t be built fast enough to make up the difference.

Solar and batteries, clustered in small-scale community energy projects or scattered across neighborhoods, may be ​“the only viable way to meet load growth” from data centers, factories, and broader economic activity, Constantine said. And by relieving pressure on utility grids, they can help bring down costs not just for those who install them, but for customers at large.

Where VPPs are already saving the day

This summer has brought new proof of how customers can turn their rooftop solar systems and batteries to the task of rescuing their neighbors from energy emergencies. Over the past two months, Puerto Rico grid operator LUMA Energy has relied on participants in its Customer Battery Energy Sharing program to prevent the grid from collapsing.

“Last night we successfully dispatched approximately 70,000 batteries, contributing around 48 megawatts of energy to the grid,” LUMA wrote in a July 9 social media post in Spanish. Amid a generation shortfall of nearly 50 MW, that dispatch helped avert ​“multiple load shedding events” — the industry term for rolling blackouts.

“There were tens of thousands of batteries already there that just needed to get connected in a more meaningful way,” said Shannon Anderson, a policy director focused on virtual power plants at Solar United Neighbors, a nonprofit that helps households organize to secure cheaper rooftop solar. ​“The numbers have been really proven out this summer in terms of what it’s been able to do.”

Puerto Rico’s VPPs are managed by aggregators — companies that install solar and battery systems and control them to support the grid. Tesla Energy, one such aggregator, provides live updates on how much the company’s Powerwall batteries are contributing to the system at large.

The impacts of distributed solar and batteries aren’t always so easy to track — but clean-energy advocates are busy calculating where they’re making a difference.

During last month’s heat wave across New England, as power prices spiked and grid operators sought to import energy from neighboring regions, distributed solar and batteries reduced stress on the grid. Nonprofit group Acadia Center estimated that rooftop solar helped avoid about $20 million in costs by driving down energy consumption and suppressing power prices.