First-of-its-kind partnership between California’s largest utility and nation’s leading provider of clean energy as a subscription service helped strengthen the state’s energy grid with home solar-plus-storage systems
By Paul Doherty
Peaking at nearly 32 megawatts from 8,500 solar-plus-storage residential systems, Sunrun and PG&E customers provided consistent, reliable clean energy to California’s power grid through the summer and fall of 2023 through an exclusive partnership between PG&E and Sunrun (Nasdaq: RUN), the nation’s leading provider of clean energy as a subscription service.
The Energy Efficiency Summer Reliability Program, also known as Peak Power Rewards, is a comprehensive and fully operationalized residential solar and storage distributed power plant. The program quickly achieved its maximum enrollment of 8,500 customers and provided a consistent average of 27 megawatts of power during evening peak hours for more than 90 consecutive days. With an instantaneous peak output of nearly 32 megawatts, the program frequently supplied the grid with up to 30 megawatts – sufficient power for more than 20,000 homes.
Sunrun managed the participating fleet of home batteries to provide power to PG&E in the same way that a centralized, traditional power plant would. However, Peak Power Rewards was operational within six months of contract signature, a timeframe not possible when building traditional power plants.
“The Peak Power Rewards program achieved a customer participation rate and power supply volume that’s never been accomplished before,” said Sunrun CEO Mary Powell. “PG&E was able to confidently rely on the renewing daily resource of Sunrun’s fleet of home solar and storage systems. We are rapidly transitioning to a storage-first company and the results of this partnership highlight the unique capability that distributed power plants provide communities.”
Sunrun’s distributed power plant programs use software to seamlessly manage the discharging of thousands of home batteries onto the grid in coordination with utility needs, making it so customers don’t need to take any action. Peak Power Rewards created a favorable situation for PG&E, Sunrun and their shared customers. Enrolled battery systems discharged energy back to the grid every day from 7 p.m. to 9 p.m. during the months of August through October, a critical window when energy needs are highest in California. In exchange, customers received an upfront payment of $750 and a free smart thermostat for participating. Batteries enrolled in the program retain enough energy to meet personal, essential needs in the event of a local power outage in their area.
“Working together with partners like Sunrun is a win-win-win for our customers, the electric grid and California as a whole. Solar-plus-storage plays a significant role in California’s clean energy future and we’re proud of our customers who are leading the charge with their clean energy adoption. Every day, we’re looking at new and better ways to deliver for our hometowns while ensuring safety, reliability and resiliency for our customers,” said Patti Poppe, CEO of PG&E Corporation.
PG&E is the nation’s utility leader in both rooftop solar and behind-the-meter storage, having connected nearly 820,000 customers with rooftop solar to the electric grid totaling approximately 8,039 megawatts of capacity and with nearly 75,000 PG&E customers having installed and connected storage systems to the grid in PG&E’s service area, totaling more than 670 megawatts of capacity. These customers could on average rely on over 10 hours of backup power using their storage system, a critical resource for grid resiliency, particularly during storms, heatwaves, and emergency energy alerts.
“What is happening in California will soon need to be replicated across the country,” Powell said. “Residential solar-plus-storage systems networked together as distributed power plants are answering the demand call by providing flexible, on-demand power stabilization while also guarding against increasing rates.”
Sunrun is the nation’s largest provider of distributed power plant programs with years of experience managing a fleet of tens of thousands of home batteries and assisting utilities with demand response planning. Unlike traditional power plants, Sunrun’s distributed power plants can quickly be set up and operationalized without the need for costly new infrastructure, as was the case with the PG&E partnership. Sunrun and PG&E are currently exploring possibilities for future programs that will jointly benefit customers, electric grid resiliency, and Californians overall.
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