Spearmint Energy secures investment for 400 MWh battery energy storage across two projects
Published by Abby Butler,
Editorial Assistant
Energy Global,
Spearmint Energy, a next-generation energy company bringing stable, secure, and cost-effective energy solutions to the power grid with large scale battery storage, has closed an equity investment in Tierra Seca and Seven Flags, two 100 MW/200 MWh battery energy storage systems (BESS), located in Del Rio and Laredo, US, respectively.
The investment, which will support the addition of 400 MWh of energy storage capacity to ERCOT, was provided by Kyuden International Corp., an electricity-focused energy solutions provider and the overseas business arm of Kyuden Group, Japan’s leading energy utility company.
Andrew Waranch, Founder, President, and CEO of Spearmint, commented: “As power demand continues to rapidly increase across the US, accelerating the need for battery energy storage, we are pleased to partner with Kyuden International to advance our development of reliable and affordable energy solutions. We believe Kyuden International’s significant investment in Tierra Seca and Seven Flags underscores their confidence in Spearmint’s ability to safely and efficiently bring projects online that enhance grid stability and meet the needs of communities across ERCOT.”
Kyuden International’s investment in Tierra Seca and Seven Flags marks the firm’s first in US-based BESS following its earlier investments in a solar power generation portfolio and four gas turbine combined cycle power plants.
Takashi Mitsuyoshi, CEO at Kyuden International, added: “Our entry into the US battery energy storage market required a partner with both vision and capability, and we believe Spearmint embodies both. Spearmint’s technical expertise, scalable platform, and execution competence in complex markets make the company an exceptional fit for our investment strategy. We look forward to helping Spearmint advance critical infrastructure that strengthens grid resilience nationwide.”
The close of Kyuden International’s equity investment builds on the over US$250 million of financing Spearmint secured from Manulife, East West Bank, Investec, and Sugar Creek Capital in 2Q25 to support the construction of Tierra Seca and Seven Flags. M.A. Mortenson Company is leading construction of the projects, both of which utilise Sungrow Power Supply Co., Ltd’s state-of-the-art PowerTitan 2.0 energy storage platform. Both projects commenced operations in late December 2025.
Paul Hastings LLP and K&L Gates LLP served as legal counsel to Spearmint and Kyuden International, respectively.
For more news and technical articles from the global renewable industry, read the latest issue of Energy Global magazine.
Energy Global's Winter 2025 issue
Don’t miss out on our final issue of Energy Global this year! The Winter issue begins with a regional report on Africa’s energy future, with articles on topics such as wind turbine components, geothermal drilling & operations and energy storage technology. With contributors including Magnomatics, Flyability, Bachmann electronic GmbH, NOV, and more, don’t miss out!
Read the article online at: https://www.energyglobal.com/energy-storage/08012026/spearmint-energy-secures-investment-for-400-mwh-battery-energy-storage-across-two-projects/
You might also like
Hvalávirkjun hydropower project certified Gold under the HSS
The Hvalávirkjun hydropower project in Iceland has been awarded Gold certification under the Hydropower Sustainability Standard.