Texas BESS: GridStor inks tolling agreement for 350 MWh project, Sunrun teams up with NRG Energy for low-cost home storage

There has been a lot of activity in the Texan BESS market – which some would describe as saturated – and this momentum is continuing with BESS developer GridStor announcing the completion of a tolling agreement for its 150 MW/300 MWh battery facility in Hidalgo County.

In February 2025, ESS News reported that GridStor purchased the BESS from Balanced Rock Power.

It did not name the partner in the new tolling agreement but specified they are a Fortune 500 company. Construction has already begun on the BESS, dubbed the Gunnar Reliability Project. It is expected to begin operations by the end of 2026 and it will provide the power equivalent to serving approximately 95,000 Texas households during the ERCOT grid’s peak demand times.

“At a time of rapidly increasing power demand, battery energy storage helps ensure affordable, reliable power to households and Lower Rio Grande Valley businesses,” said Chris Taylor, CEO of GridStor. “We are proud to increase our commitment to building battery storage facilities that help Texas sustain its historic economic expansion and deliver cost-effective power.”

GridStor already has one BESS operating in Texas. The 220 MW Hidden Lakes Reliability Project in Galveston County began operations earlier this year.

The Goldman Sachs-backed company has a pipeline of more than 3 GW of BESS projects in development or under construction in the United States – the region it primarily targets.

In addition to GridStor’s tolling agreement and construction announcement in Hidalgo County, other energy storage players have been making moves in the Texan market.

Residential battery storage, solar, and home-to-grid power plants provider Sunrun is partnering with NRG Energy to deliver distributed energy solutions to Texan consumers.

Sunrun will combine its solar-plus-storage systems with optimized rate plans and smart battery programming through Reliant, NRG Energy’s retail electricity provider.

Together, the companies will be developing offers to aggregate and dispatch these distributed power assets to provide electricity to Texas’s grid during periods of peak demand. Sunrun will be paid for aggregating the capacity and participating Reliant customers will be compensated by Sunrun for sharing their stored solar energy.

“This partnership demonstrates the scale and strength of Sunrun’s storage and solar distributed power plant assets,” said Sunrun CEO Mary Powell.

By focusing on distributed energy systems, the companies hope to meet Texas’ growing demand for energy and ease the pressure on the ERCOT grid.

“We are delivering critical energy infrastructure that gives Texas families affordable, resilient power and builds a reliable, flexible power plant for the grid,” said Powell.

“Texas is growing fast, and our electricity supply must keep pace. By teaming up with Sunrun, we’re unlocking a new source of dispatchable, flexible energy while giving customers the opportunity to unlock value from their homes and contribute to a more resilient grid,” said Brad Bentley, EVP, President of NRG Consumer. The executive added that the partnership with Sunrun is a “major step” in achieving NRG Energy’s goal of creating a 1 GW virtual power plant by 2035.