Sunrun Building Residential Solar/Storage for Three Bay Area CCAs

February 2022

The solar/storage installations are designed to meet resource adequacy requirements

Three community choice aggregators (CCAs) in the San Francisco Bay area signed contracts with San Francisco-based Sunrun in 2020 and have already seen 850 solar plus storage systems under contract or installed in their residential service territories. The agreements are designed to meet state-mandated resource adequacy requirements imposed on CCAs and utilities by the California Public Utilities Commission.

Sunrun will do this by moving power daily from solar plus storage systems installed on residential roofs to transmission lines to satisfy the CCAs’ resource adequacy requirement.

Sunrun is paying residential owners who agree to give up a portion of their stored power. Customers are offered the incentive of $1,250 to sign contracts with Sunrun. The solar/storage systems will also provide power to residences on a daily basis and in case of utility power shutoffs.

Sunrun signed the resiliency contracts with Peninsula Clean Energy, East Bay Community Energy and Silicon Valley Clean Energy Authority. Silicon Valley Power, the City of Santa Clara’s municipal utility, was part of the 2019 solicitation in which Sunrun was chosen, but it ultimately decided to opt out of a contract with the company. It is now developing its own DER resiliency program as well as a separate microgrid. (See story below.)

After fires raged through Northern and Central California in the summer of 2018 the CCAs became motivated to protect residential power in future natural disasters, and particularly during wildfire seasons when utility power is shut off either intentionally by the serving utility or unintentionally due to fire damage.

Resource adequacy requires utilities and CCAs to have additional generation resources during high peak demand periods to provide stability such as in a heat wave. As the Silicon Valley Energy Authority (SVCE) staff report informed its Board, “The negotiated contract is an innovative alternative approach to meeting RA obligations through reducing peak demand through the coordinated dispatch of BTM (behind the meter) resources.”

SVCE signed its contract worth $7.4 million in November 2020 with Sunrun. Details were laid out in a staff report presented to the CCA’s Board of Directors that same month. The company agreed to install between 1 MW and 7.5 MW of solar systems and battery storage ranging from 4 to 30 MWh in SVCE’s service territory. Individual solar systems vary from 1 kW to 5 kW.

The SVCE Board reported at its January 12, 2022 Board meeting 300 families had signed contracts. The goal under this contract is to sign up 750 single family projects along with five multi-family buildings. However, no multi-family properties had stepped up by the end of 2021 when these numbers were tallied.

According to a Sunrun fact sheet, storage systems are designed to supply 8 to 12 hours of backup power, depending on how much is used. According to the report Sunrun will start moving power to transmission lines beginning December 31 2022 and continue through December 31, 2032.

Sunrun did not respond when asked for comments, in particular to these numbers.

The innovative arrangement between the CCAs and Sunrun to deliver power to the grid to satisfy CCA resiliency obligations was worked out with the California Energy Commission, led by East Bay Community Energy (EBCE) according to SVCA’s staff report. They developed the load modification approach. Each year, CCAs will submit peak demand forecasts to the CEC which uses it to set the annual RA procurement obligation for each CCA.  The energy storage systems will then be dispatched on a daily basis during the highest peak hours. That decreases the CCA’s peak load and reduces its RA obligation and “thereby also reduces the wholesale energy procurement volumes usually sourced from natural gas power plants.

JP Ross, vice president of local development, electrification and Innovation at EBCE, said having the residential battery resources reduces the amount of resource adequacy we have to buy. The contract with Sunrun requires the dispatch of power from the batteries between 4:00 p.m. and 8 p.m. every week day.  When the power is out – as in the case of a public safety power shutoff (PSPS) – the solar and battery power will be available to run their essential operations at individual residences.” Ross said Sunrun always leaves 20% of the battery power as a reserve margin for residents.

At EBCE’s Resilient Home program with Sunrun, in addition to the $1,250 incentive payment, customers are also offered no-cost consultations and project quotes according to Dan Lieberman, director of marketing. He said marketing and outreach is shared between Sunrun and EBCE. As of January, Sunrun has executed contracts with 400 customers, with 1.4 MW in commercial operation according to Lieberman. He said, in a February 3 email, “The associated PV capacity installed with the residential battery systems is over 6 MW since program launch.”

Lieberman expressed concern that the CPUC’s proposed changes to Net Energy Metering “may significantly reduce program enrollments going forward.” As of this writing, the CPUC is considering modifications to its proposal and it may be months before it makes a decision.

In an email exchange, Darren Goode at Peninsula Clean Energy in San Mateo County said Sunrun will install at least 1 MW by January 1 2022 on both single family and multi-family dwellings. By mid-April 2021, the company had installed over 150 systems. He explained that Peninsula began by targeting customers who were either in a high fire threat district or who were affected by utilities shutting down transmission lines as a measure to limit wildfires from starting or spreading.  First to be targeted were customers who are on utility discount programs such as CARE, FERA or Medical Baseline rates. Goode said they are now starting to target all homeowners. As of February he had no update on new contract signings or installations.

An earlier version of this story appeared in Microgrid Knowledge in July 2021.