Energy Vault Holdings has begun construction on SOSA Energy Center, a 150MW battery energy storage project located in Madison County, Texas. The project introduces a large-scale energy storage facility to the ERCOT North market.

The facility will have a storage capacity of 300 megawatt hours and is planned to start commercial operation in the second quarter of 2027.

Energy Vault bought the project in Q4 of 2025 from Savion, a renewable energy firm of Shell plc. The construction phase is currently in progress, marking the end of development and the beginning of execution for this project.

The facility is the fourth utility-scale energy storage project the developer EnergyVault has initiated in the construction or early stage of construction under the Asset Vault portfolio. Three projects initiated the process of off-site construction in the fourth quarter of 2025, and commercial operations will begin between late 2027 and 2028.

SOSA is based within the Northern Zone of ERCOT, which is a region observing a quick surge in wind and solar capacity. Larger-scale energy storage facilities within this region are also being developed at a growing pace for grid support and energy management.

Business model

Energy Vault is developing the project through an “own and operate” business model wherein they will perform the engineering, procurement, and construction of the project and then provide services for the project in the long term. The company had ended 2025 with over $100 million in cash and liquidity, up about 65% from the previous quarter.

The project has gained site control, achieved environmental and grid interconnection milestones, and is in the advanced stage of negotiations of a long-term offtake agreement with an investment-grade counterparty.

Once fully functional, the project will be among the largest battery storage facilities operating in the market of ERCOT North.

Battery energy storage development is accelerating across the U.S., with large utility-scale projects moving into construction. The SOSA Energy Center has now entered construction in Madison County, Texas, adding 150 MW of storage capacity to the ERCOT North market and supporting the region’s growing renewable energy integration.

Across Puerto Rico, SolarMax Technology has recently secured engineering, procurement, and construction (EPC) agreements for two utility-scale battery storage projects in Humacao and Ceiba municipalities. Together, the projects will provide 400 MWh of storage capacity, with construction planned to deliver renewable electricity storage for peak demand periods and strengthen grid reliability across the island.

SOSA Energy Center Project Factsheet

Project Overview

Project Name: SOSA Energy Center

Location: Madison County, Texas

Market: ERCOT North

Developer: Energy Vault Holdings, Inc. (NYSE: NRGV)

Previous Developer: Savion (Shell plc subsidiary)

Technical Specifications

Capacity: 150 MW / 300 MWh

Technology: Battery Energy Storage System (BESS)

Product Platform: Energy Vault B-VAULT™ DC (3rd Generation)

Configuration: Grid-scale energy storage solution

Project Timeline

Acquisition Date: Q4 2025 (from Royal Dutch Shell’s Savion subsidiary)

Construction Start: Q4 2025

Expected Commercial Operation: Q2 2027

Off-site Construction Commenced: Q4 2025

Financial Projections

Total Expected Revenue: $350+ million over technical life

Annual Recurring Revenue: $17-20 million (high margin)

Offtake Agreement: 6-8 year term (advanced negotiations with investment-grade counterparty)

Construction of the SOSA Energy Center: Strategic Significance

The SOSA Energy Center represents the fourth Asset Vault project under construction and a major milestone in Energy Vault’s “Own & Operate” asset management strategy. The project is part of the Asset Vault investment platform supported by a $300 million preferred equity investment from Orion Infrastructure Capital (OIC).

Key Benefits:

Fully secured site control with clean title

Completed environmental milestones

Completed interconnection milestones

Streamlined construction process

Vertically integrated EPC and service delivery

Execution Model

Delivery Approach: Self-performed by Energy Vault

Engineering, Procurement, Construction (EPC)

Long-term service agreements

Operational control for optimized returns

Multiple revenue stream capture across project lifecycle

Market Context

The project positions Energy Vault as a key infrastructure partner in the Texas ERCOT market, supporting the state’s renewable energy integration and grid modernization efforts. Texas leads the nation in renewable energy adoption, making ERCOT a cornerstone market for Energy Vault’s growth strategy.

Compliance & Regulatory Status

‘Safe harbored’ status achieved

FEOC (Foreign Energy Operating Company) compliant

Part of broader Q4 2025 investment program for multiple projects

Company Portfolio Impact

With SOSA Energy Center under construction, Energy Vault’s total Asset Vault portfolio under operation and construction exceeds 340 MW, demonstrating rapid scaling of the company’s energy asset management capabilities.