US retail giant Walmart has made a strategic investment in home battery storage firm Base Power, while Sunrun has doubled the size of its home battery VPP in Puerto Rico.
Base Power announces strategic agreement with Walmart
Retail giant Walmart has announced a strategic investment in Texas-based energy storage company Base Power.
The investment was announced 30 October alongside a commercial agreement that will make Base’s home battery energy storage system (BESS) and electricity offerings available to Walmart customers and Sam’s Club members.
The partnership is designed to widen access to residential BESS, with Base’s home battery systems intended to lower household energy costs while the grid is operating normally and to provide backup power during outages.
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From November, customers and members who sign up for an eligible Base home BESS at participating Walmart and Sam’s Club locations will receive a 20% discount on Base Power’s standard upfront installation fee.
Under Base’s business model, the company installs, owns and maintains its BESS, with customers paying only an upfront installation fee rather than the full cost typically associated with traditional whole-home backup solutions.
In parts of Texas, Base also offers retail electricity plans aimed at helping customers reduce their bills.
The rollout will begin in Texas, where Base already has an established presence. Walmart has said it expects to expand the offering to additional US markets over time, though availability, pricing, and savings will vary by location, utility service area, and individual customer circumstances.
Customers and members will be able to speak with Base representatives in person at participating Walmart and Sam’s Club stores to learn more about the available services and enrol.
The Walmart partnership follows a period of rapid expansion for Base Power. In August, the company announced a US$1 billion Series D funding round at a US$13 billion post-money valuation, alongside the commercial launch of its new residential battery, Base Core, which began production at the company’s Austin, Texas factory.
The Series D round was led by Ribbit, Addition, Valor Equity Partners, and JPMorganChase’s Strategic Investment Group, with participation from a range of other venture and investment firms, following an earlier US$1 billion Series C round closed in October 2025.
Sunrun’s Puerto Rico VPP doubles to over 60,000 customers
Residential solar and battery installer Sunrun has announced that participation in its virtual power plant (VPP) in Puerto Rico has doubled to more than 60,000 customers.
Announced 3 November, the figure represents close to 70,000 home batteries connected to the VPP.
The VPP can deliver 45MW of dispatchable power for four-hour periods, supporting the island’s electric grid during periods of strain.
Since April, Sunrun has dispatched the power plant more than 60 times to help address energy shortfalls and avoid rolling blackouts. During an extended spell of unseasonably warm weather this autumn, the company dispatched its fleet of home batteries to the grid for 18 consecutive days from 13 October.
Sunrun’s Puerto Rico VPP has grown rapidly since 2024, when roughly 4,000 customers were enrolled. Enrolment rose to more than 30,000 by 2025 and has since climbed past 60,000, making Sunrun the largest aggregator participating in Puerto Rico’s Customer Battery Energy Sharing (CBES) programme.
Puerto Rico’s grid operator, Luma Energy, has publicly stated that energy drawn from home batteries has helped maintain system stability, prevent outages, and avoid previously announced load-shedding measures during periods of generation shortfall.
Participants in Sunrun’s VPP choose how much of their stored energy to share, with most customers contributing only a portion of their total battery capacity in order to retain sufficient reserve power for their own use during grid outages.
Participants receive financial compensation for the energy they share, while Sunrun earns recurring revenue from operating the aggregated resource.
The CBES programme, which underpins Sunrun’s Puerto Rico operations, was established by the governing board of the Puerto Rico Electric Power Authority (PREPA) and is overseen by the Puerto Rico Energy Bureau (PREB).
In April, PREB approved a motion from Tesla, Sunrun, and SunStrong Management to continue auto-enrolling customers into the programme on an opt-out basis for summer 2026, following what the companies described as the successful use of the same approach in summer 2025, when participation expanded from a few thousand to around 81,000 customers.
With this latest approval, aggregators have suggested participation could rise beyond 120,000 customers.
The approved capacity accessed through CBES represents only a fraction of the total battery capacity installed on participating homes, with aggregators balancing residents’ need for backup power against the grid’s need for dispatchable capacity.
