Google backs 100 MWh zinc, 280 MWh lithium storage project in West Virginia

Google has agreed to buy power from a large solar and battery project planned for a reclaimed coal mine site in Kanawha County, West Virginia. The project, called Mammoth Solar, is being built by MN8 Energy and combines an 86 MW solar array with two kinds of battery storage: 70 MW/280 MWh of lithium-ion batteries and 10 MW/100 MWh of a longer-duration zinc-based battery system made by Eos Energy, called Z3. The zinc battery can discharge power for 10 hours at a time, longer than typical lithium-ion systems, which helps stretch out solar power into more hours of the day.

This isn't a program homeowners can sign up for. It's a utility-scale project meant to supply power to Google's data centers in the region, including one planned in West Virginia. The solar part is expected to start operating in 2028, the lithium-ion batteries in 2029, and the zinc battery system in 2030. MN8 says it will be the first large-scale long-duration storage project of its kind in the state.

The project is expected to cost up to $350 million to build, create about 200 construction jobs, and generate roughly $4 million in property tax revenue for Kanawha County and local schools over its first 20 years. For nearby homeowners, the practical impact is mostly local: jobs during construction, some added tax revenue, and a large energy project reusing old coal mine land rather than new open space. It does not come with any rebate or incentive for home energy upgrades.