Sunrun is landing contract after contract to put solar-charged residential batteries to work serving grid needs. On Thursday, it picked Silicon Valley energy management software startup AutoGrid to help it optimize this growing fleet. 

Sunrun, the country’s leading solar installer, joins a roster of AutoGrid clients using its Flex software to manage distributed energy resources, ranging from smart thermostats for utility demand response programs to industrial cooling and heating systems and commercial microgrids.

In Sunrun’s case, it’s using features of AutoGrid’s software to manage the Brightbox batteries being installed by its solar customers as they are pledged to support utility grid needs in projects ranging from Hawaii and California to Massachusetts and New York.

“Sunrun has tens of thousands of batteries they’re deploying,” Amit Narayan, AutoGrid CEO, said in an interview. “You really need the power of big data and machine learning to do this in a scalable manner.”

Fleets of batteries, meet optimization software

Sunrun’s move into grid services is an outgrowth of its increasing emphasis on adding batteries to its residential solar systems. Storage can increase value for customers in certain markets where storing solar energy can be more lucrative than sending it back to the grid under changing net metering regimes. It’s also a way for Sunrun and other residential solar and inverter players like Tesla, Vivint Solar, SolarEdge and Enphase to boost revenue from each installation. 

Sunrun officially launched its Grid Services business in 2017 in search of ways to increase the value of those batteries by tapping their potential to serve grid needs, ranging from reducing household load as part of utility demand response programs to bidding into grid operator capacity and ancillary services markets. Sunrun’s grid services pipeline recently hit a value of $50 million, CEO Lynn Jurich said last month.

But managing fleets of batteries to maximize grid services revenue is a complex task, particularly when those grid needs have to be met with the same stored energy that’s being held in reserve to shift customers’ energy consumption to times of the day when that energy is less costly, or for use as backup power during grid outages. 

Creating the software to enroll batteries in utility and grid operator programs, analyze the value of multiple grid opportunities and dispatch them to optimize that value is an expensive and time-consuming task — and one that requires expertise across multiple utility and market jurisdictions. 

“That’s something that Sunrun did try some internal solutions [for], and they realized this problem is very challenging,” Narayan said. AutoGrid has already done this work with dozens of utilities and energy services providers, which “reduces a lot of overhead for the project developers.”   

"AutoGrid will enhance our capabilities to offer utilities an aggregated fleet of home solar and battery resources to make the electric grid cleaner and more resilient, while reducing costs for all energy consumers," Jurich said in a prepared statement. 

A growing market for optimizing distributed energy 

AutoGrid, which provides its software as a service, has been shifting from its early focus on utility customers to serving renewable energy developers such as NextEra, French oil major Total and China’s CLP Group, as well as developers of aggregated "virtual power plants" consisting of on-site generation and flexible loads. More than half of AutoGrid's business is now with non-utility companies, Narayan said. 

“We’re the plumbers behind the scenes, connecting everything and making sure the money is flowing," he said. "Our customers have a lot of options in terms of how they set up their programs.” 

The Redwood City, California-based startup, which has raised more than $75 million in venture funding, competes with companies such as Enbala and EnergyHub in the field of connecting and managing behind-the-meter energy assets to serve grid needs. 

Sunrun isn’t AutoGrid’s first behind-the-meter battery customer. In 2016 it partnered with sonnen, the German solar-battery startup acquired last year by Shell Energy Services, which is an investor in AutoGrid. Sonnen landed its first U.S. grid services contract in August 2019, after building similar virtual power plant arrangements in Germany. 

And in 2018, AutoGrid partnered with Swell, a Los Angeles-based startup that’s installing batteries in 3,000 homes to provide grid services to Southern California Edison, a utility that AutoGrid is also working with on electric vehicle charging pilot programs. Sunrun just announced a new pilot program with SCE to offer existing battery-equipped customers $250 to turn over their batteries to utility control, so the program can test different combinations of dispatch strategies. 

Similarly, Sunrun is one of the earliest participants in a “bring-your-own-battery” program with utility National Grid in Massachusetts and Rhode Island. While that residential program is run by EnergyHub, National Grid is working with AutoGrid to manage about 400 megawatts of commercial and industrial demand resources across its New England and New York service territories.