Spearmint Energy Secures Investment from Kyuden International Corporation for 400 MWh Battery Energy Storage Across Two Projects in ERCOT

Marks Kyuden International’s Inaugural U.S. Battery Energy Storage Investment

Follows Spearmint’s Successful Close of $250 Million in Financing for Tierra Seca and Seven Flags Projects in Q2 2025

Both 100 MW / 200 MWh BESS Commenced Operations in Late December 2025

MIAMI--(BUSINESS WIRE)--Spearmint Energy (“Spearmint” or the “Company”), a next-generation energy company bringing stable, secure and cost-effective energy solutions to the power grid with large-scale battery storage, has successfully 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, respectively. The investment, which will support the addition of 400 MWh of energy storage capacity to ERCOT, was provided by Kyuden International Corporation (“Kyuden International”), 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 Chief Executive Officer of Spearmint, said, “As power demand continues to rapidly increase across the U.S. 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 U.S.-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 U.S. 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 $250 million of financing Spearmint secured from Manulife, East West Bank, Investec and Sugar Creek Capital in Q2 2025 to support the construction of Tierra Seca and Seven Flags. M.A. Mortenson Company is leading construction of the projects, both of which utilize 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.

About Spearmint Energy

Spearmint Energy (“Spearmint” or the “Company”) is a leading energy company focused on developing, owning, operating, and optimizing battery energy storage systems (“BESS”) to reduce grid volatility and increase system resiliency. Spearmint currently operates a 150MW/300 MWh BESS project in West Texas, and has 23 projects, totaling over 15GWh of capacity, under development in 12 states across 5 U.S. regions. Headquartered in Miami, with an additional office in Minneapolis, the Company employs over 70 professionals and is guided by strong values rooted in people, partnerships, and the planet.

For more information, please visit: https://www.spearmintenergy.com/

About Kyuden Group and Kyuden International

Kyushu Electric Power Company, also known as Kyuden Group is a leading energy company in Japan, reporting a net income of $1.5 billion in FY2024. The Group has been supplying electricity to more than 8.5 million customers and businesses for over 70 years in the Kyushu region in the south of Japan. Its primary goal is to provide safe, reliable, and affordable energy while striving to achieve Carbon Neutrality by 2050. Kyushu Electric Power is actively driving the transition to a sustainable society by operating nuclear power generation, expanding renewable energy production, and implementing climate-smart energy solutions.

Leveraging the technology, expertise, and network developed through the Group’s domestic and global operations, Kyuden International engages in power generation, power distribution, and other businesses across Asia and beyond. Kyuden International intends to expand business development opportunities by cooperating with various business entities and promoting initiatives that contribute to low-carbon and decarbonization efforts tailored to the specific circumstances in each country. These efforts support the Group’s vision of achieving a carbon-neutral society.