Spearmint Energy Brings 400 MWh of Battery Storage Online in ERCOT
Event summary
- Spearmint Energy’s Tierra Seca and Seven Flags projects, totaling 400 MWh of battery storage, achieved commercial operation in late December 2025.
- The projects, located in Del Rio and Laredo within the ERCOT market, were constructed by Mortenson and utilize Sungrow’s PowerTitan 2.0 platform.
- Spearmint secured over $250 million in construction financing in Q2 2025 and received an investment from Kyuden International in January 2026.
- Spearmint now operates 350 MW / 700 MWh in ERCOT and has over 20 projects totaling 15 GWh under development across 13 states.
The big picture
Spearmint Energy’s successful deployment of 400 MWh of battery storage in ERCOT underscores the growing role of energy storage in stabilizing power grids. The projects, completed on schedule and with significant financing, highlight the increasing collaboration between developers and EPC contractors in scaling energy infrastructure. As ERCOT faces rising demand, the strategic importance of flexible storage capacity is becoming more pronounced, positioning Spearmint as a key player in the energy transition.
What we're watching
- ERCOT Reliability
- How the addition of 400 MWh of storage will impact ERCOT’s grid stability amid growing power demand.
- Execution Risk
- Whether Spearmint can sustain its project development pace with over 20 projects in the pipeline.
- Financing Dynamics
- The pace at which Spearmint secures additional funding for its expanding portfolio of energy storage projects.
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