Google backs 100 MWh zinc, 280 MWh lithium storage capacity in US

MN8 Energy said it will build “Mammoth Solar,” an 86 MW solar project in Kanawha County, West Virginia, paired with 70 MW/280 MWh of lithium-ion storage and 10 MW/100 MWh of Eos Energy Enterprises’ Z3 zinc-based LDES system.

Google will purchase the energy, capacity and clean energy attributes of the project under a long-term agreement, according to MN8.

A company spokesperson told ESS News that the project is the same Mammoth Solar development previously permitted in Kanawha County, with battery storage added during the Public Service Commission review process after initial permitting.

Google’s participation as offtake partner came after the project was already in development, but the tech giant helped shape the technologies that were ultimately selected. The megawatt allocation for the project’s Eos storage component is drawn directly from MN8 and Eos’ previously announced master supply agreement, said the spokesperson.

The project is built on a reclaimed coal mine site. MN8 said it will own and operate the integrated portfolio, which the company says is designed to convert intermittent solar generation into a single dispatchable resource matched to the load profile of Google’s regional data centers, including a planned West Virginia facility.

MN8 said the Eos Z3 system is designed to provide 10 hours of discharge duration, extending the availability of solar generation beyond the shorter-duration lithium-ion storage in the portfolio. The company said this marks Google’s first project using Eos’ Z3 technology.

The solar component is expected to reach commercial operation in 2028, the lithium-ion storage in 2029 and the Eos LDES system in 2030, MN8 said. The company said the project represents the first commercial-scale LDES deployment in West Virginia.

MN8 estimates the project represents up to $350 million in capital investment and will generate approximately $4 million in property tax revenue for the county and local schools over its first 20 years of operation. Construction is expected to create approximately 200 jobs, said the company.

Lucia Tian, director of advanced energy technologies at Google, said the company is committed to backing solutions that serve its data center capacity needs while accelerating progress toward cleaner, more affordable energy systems, adding that the collaboration with MN8 and Eos aims to deploy a portfolio of round-the-clock technology solutions to help power its digital infrastructure.

Company officials said the project reflects MN8’s approach of building a solution around a customer’s specific energy profile, engineering proven and emerging technologies into a single dispatchable resource. The Z3 system is designed to extend the value of clean generation across more hours, strengthen the overall portfolio and deliver more dependable capacity when the grid needs it most, they said.