The ‘battery-only’ model enables households without their own photovoltaic systems to participate in the virtual power plant. Sonnen entered the Texas market at the beginning of 2025 together with partners Solrite and Abundance Energy, and the programme has since grown to around 3,000 customers. The company aims to add approximately 10,000 more households by the end of 2026.
No upfront investment
The battery-only model provides households with a 60 kWh SonnenBatterie without requiring upfront investment. The system also functions as a backup unit, maintaining power supply during outages. Instead of an initial payment, customers pay a monthly fee of 20 US dollars and a fixed electricity rate of 12 cents per kilowatt hour, below the state average. In return, the batteries are integrated into the virtual power plant, where they provide grid services and participate in energy trading, helping to refinance the programme.
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“Flexibility is becoming one of the most valuable resources in modern energy systems. This is particularly evident in a market such as Texas, where rising consumption and growing renewable generation meet constrained grid capacity. What is unfolding here offers a preview of challenges other energy systems are likely to face. Unlike Germany, the market is comparatively technology-neutral, allowing the most cost-effective solutions to compete. That is a key reason for our success here,” said Oliver Koch, CEO of Sonnen.
Electricity consumption in Texas is rising sharply, driven by strong population growth and the rapid build-out of new data centres, particularly for AI applications. At the same time, the share of wind and solar generation continues to increase. While these sources provide large volumes of low-cost electricity, their output remains weather-dependent and variable. Rising demand combined with fluctuating supply is a typical driver of price volatility in wholesale power markets.
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There is also a structural factor to consider: the Texan power market operates largely independently of the wider US grid. In periods of tight supply, the state has limited ability to import electricity from neighbouring regions or export surpluses. This relative isolation contributes to higher price volatility and increases the risk of supply disruptions.
Supply security and affordability
Networked SonnenBatteries are designed to help address this challenge by operating collectively as a virtual peaking resource. They store electricity when supply is abundant and feed it back into the grid when demand rises, helping to balance the system. This supports grid stability while offering participating households greater supply security and predictable energy costs.
In this way, residential storage assumes functions traditionally associated with conventional power plants, including load shifting during periods of high solar and wind output, provision of balancing services, frequency support and congestion management. Such aggregation facilitates the integration of large-scale renewables, reduces reliance on fossil-based peaking capacity and enhances overall grid management.
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Sonnen operates virtual power plants across several US states and Canada, and has also aggregated residential storage fleets in Germany and Belgium. (hcn)
