SOSA Energy Center: 150 MW / 300 MWh Microgrid in Madison
- Microgrids News On-Site Generation & Microgrids
Marin Holt
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- 5 minutes read
- 150 MW / 300 MWh, a two-hour system in Madison County, Texas, inside the ERCOT North zone
- Commercial operation targeted for the second quarter of 2027
- Energy Vault acquired the project from Shell subsidiary Savion in Q4 2025
- Built under the Asset Vault platform, backed by $300 million of preferred equity from Orion Infrastructure Capital
- Energy Vault projects $17 million to $20 million a year and more than $350 million over the project's technical life
Energy Vault Holdings has broken ground on the SOSA Energy Center, a 150 MW / 300 MWh battery in Madison County, Texas, inside the ERCOT North zone. The company is targeting commercial operation in the second quarter of 2027. Energy Vault acquired the project from Savion, a Shell subsidiary, in the fourth quarter of 2025 and is building it under its Asset Vault platform.
SOSA Energy Center Underway in Texas
Construction has officially begun on the SOSA Energy Center, a large-scale energy storage project developed by Energy Vault Holdings in Madison County, Texas. According to a January 6, 2026 report by pv magazine USA, the facility is designed to deliver 150 MW of power and store 300 MWh of energy. Savion had carried the project through permitting and interconnection before the sale.
Project Specifications and Context
The Asset Vault platform is backed by a $300 million preferred equity commitment from Orion Infrastructure Capital, and SOSA is the first project to start construction under it. Energy Vault is doing engineering, procurement and construction itself and holds the long-term service agreement, so it carries both build and availability risk rather than passing them to a third-party contractor. The system uses the company’s B-VAULT DC product. Energy Vault puts its total portfolio in operation or under construction at more than 340 MW.
Critical Perspective
The SOSA Energy Center will have 150 MW of power capacity. That is slightly smaller than the 175 MW / 350 MWh ERCOT North project Energy Vault acquired near Dallas in March 2026. Will this 300 MWh storage system truly provide the promised grid resilience at its projected cost?
Why It Matters
A two-hour battery is sized for the evening ramp and for ancillary services, not for multi-day outage cover, so SOSA’s economics turn on how often ERCOT prices spike inside a two-hour window. Energy Vault’s own projection implies the same thing: $17 million to $20 million a year against more than $350 million across the project’s technical life. The company has not broken those figures down by revenue stream, so the split between energy arbitrage and ancillary-service payments is not public, and neither is the price path it assumes for ERCOT North through 2027.
