Executive Summary

MN8 Energy, a New York-based power platform, and Eos Energy Enterprises, a US-based manufacturer of zinc-based long-duration energy storage systems, are collaborating with Google on the Mammoth Solar project in Kanawha County, West Virginia. The project will combine 86 MW of utility-scale solar with 70 MW/280 MWh of lithium-ion storage and 10 MW/100 MWh of Eos Z3 zinc-based long-duration storage.

MN8 has designed Mammoth Solar as an integrated solar and storage project that combines short- and long-duration energy storage. The solar component is expected to reach commercial operation in 2028, followed by the lithium-ion storage system in 2029 and the long-duration storage system in 2030. The Eos Z3 system is designed to provide 10 hours of storage, extending the availability of solar generation beyond shorter-duration storage resources.

Under the agreement, Google will purchase the project's energy, capacity, and clean energy attributes for the grid serving its regional data centers. The project is expected to become West Virginia's first commercial-scale long-duration energy storage deployment. It is being developed on a reclaimed coal mine and is expected to involve up to $350 million in capital investment.

MN8 estimates that the project will generate approximately $4 million in property tax revenue for Kanawha County and local schools during its first 20 years of operation, with additional revenue expected over the following 15 to 20 years. Construction is expected to create approximately 200 jobs, along with additional full- and part-time roles during the project's operating life. The Eos system will be supplied under the previously announced MN8-Eos Master Supply Agreement.