Last fall, community-choice aggregators serving three Northern California counties announced plans to deploy thousands of solar-battery systems to provide backup power to residents facing the threat of fire-prevention blackouts. Now they’ve picked Sunrun, the leading U.S. rooftop solar installer and behind-the-meter battery aggregator, to get it done. 

Under the terms of the deal, Sunrun will install up to 20 megawatts of solar-battery systems for about 6,000 homes served by CCAs East Bay Community Energy, Peninsula Clean Energy and Silicon Valley Clean Energy. 

The goal is to offer vulnerable customers backup power in the likely event that utility Pacific Gas & Electric is forced to shut off power to reduce the risk of starting a catastrophic wildfire, such as the Nov. 2018 Camp Fire that killed 86 people, caused billions of dollars of damages and drove the utility into bankruptcy last year. 

Sunrun and the CCAs are already enlisting customers and want to deploy the systems as rapidly as possible, with the aim of getting at least some installed in time for this year’s fire season and the majority done in time for next year’s likely blackouts.

Sunrun’s batteries will help ease peak demand

Last year’s blackouts left millions of residents without power, some for days at a time. PG&E, which exited bankruptcy protection last month, has said it will need to continue these fire-prevention shutoffs for years to come. And this year’s fire season is expected to be more dangerous than last year’s due to reduced precipitation and drier conditions, making shutoff events potentially more likely this year. 

That grim reality is putting pressure on PG&E and the communities it serves — including the increasing number served by CCAs — to find cost-effective backup power options to ride through outages. 

The contracts with Sunrun are designed to do that by offering a $1,000 discount to customers buying one of Sunrun’s Brightbox battery-solar systems, and tapping the grid services value of the batteries to pay for the discount, JP Ross, a senior director at East Bay Community Energy, said in an interview. 

“We are paying Sunrun and the end customer for the ability to use those batteries to manage our peak load,” he said. Sunrun will aggregate 5 megawatts of capacity to reduce EBCE’s peak demand forecast with the California Energy Commission, as well as serve system resource adequacy requirements set by the California Public Utilities Commission. 

Bidding the systems as resource adequacy will help the CCAs reduce their reliance on the natural-gas-fired power plants that still provide most of the state’s peaking power needs. “We want those batteries to be discharged during the highest-cost periods, and that tends to be the same times as the highest carbon emissions,” Ross said.

Sunrun’s contracts represent the residential portion of the 30 megawatts initially targeted by the three CCAs and municipal utility Silicon Valley Power in their November joint solicitation. The remainder will be announced when SVP finalizes its plans and all four commit to a commercial storage vendor, Ross said. 

Sunrun already seeking participants in Bay Area

To help their most vulnerable customers, the three CCAs have carved out a portion of their deployments for low-income and disadvantaged communities. In EBCE’s case, at least 20 percent of its capacity will go to low-income single- and multifamily housing, Ross said. 

The CPUC has directed hundreds of millions of dollars from the state’s Self-Generation Incentive Program (SGIP) to cover almost the entire cost of battery backup systems for low-income and medically vulnerable residents and critical facilities in high fire-threat areas. That’s “a program that we’ll be focused on” to lower costs for those customers, he said. 

Sunrun is in charge of balancing CCAs’ grid services needs with their customers’ backup power needs. The 5 megawatts of capacity that Sunrun will provide EBCE is smaller than the total battery capacity it will be installing, to ensure an ample supply of stored energy to serve both purposes. 

Sunrun is already seeking out customers in the Bay Area to reach its 6,000-home target, Nick Smallwood, Sunrun’s vice president of business development and grid services, said in an interview. Being able to tap CCA data to identify customers who stand to be most harmed by preventative blackout events, such as those who lost power during last year’s outages, will speed up its outreach, he said. 

Meanwhile, Sunrun is tapping state programs like SGIP, or the SOMAH program that offers battery incentives for low-income multifamily housing, to reduce the cost for low-income residents, Smallwood said. It’s also looking for existing customers to add to each CCA’s grid service capacity, he added. 

A test case for behind-the-meter solar-storage grid resiliency 

Sunrun is in the midst of deploying solar-battery systems for grid services in multiple states, including a 20-megawatt deployment in New England to provide capacity starting in 2022 and a contract to install up to 1,000 of its Brightbox batteries by 2024 to provide grid services to utility Hawaiian Electric

Last month it won contracts with California utility Southern California Edison and New York utility Orange & Rockland, a Con Edison subsidiary, each of which will target up to 300 Brightbox-equipped homes to turn their systems over to utility control in exchange for credits or installation discounts. 

But this new deployment represents Sunrun’s largest aggregation to date along such an aggressive timeline and the first to prioritize backup power. That could help test the company’s long-standing proposition that solar-storage systems could become a central part of California’s long-term grid resiliency goals. 

PG&E withdrew its plan to deploy hundreds of megawatts of natural-gas-fired generators at substations earlier this year amid opposition from CCAs, communities and environmental groups. As a stopgap measure, the utility has readied up to 450 megawatts of mobile diesel generators for communities in high-fire-threat regions. But the CPUC has ordered PG&E to come up with alternatives to using these polluting generators as quickly as possible. 

Networks of solar-battery systems could provide a cleaner option, and CCAs and solar and battery industry groups have pressed for policies that could integrate them into broader utility efforts to mitigate the worst impacts of fire-prevention blackouts. 

While there are questions about whether individual solar-battery systems can be relied on for backup power during outages that last days, the 9.8-kilowatt-hour capacity of a Brightbox battery can last for days as long as it’s able to recharge from its solar panels by day and is powering a reduced set of essential loads, Smallwood said. And unlike a centralized microgrid or emergency backup power system, even newly installed systems can “actually impact households within days of when we reach them.”