Overview
- The agreement, announced Wednesday, Sept. 2, 2026, commits Google to buy the energy, capacity and clean attributes from Mammoth Solar, an 86 MW solar project paired with 70 MW/280 MWh of lithium-ion batteries and a 10 MW/100 MWh Eos Z3 long-duration system.
- Eos’s Z3 uses an aqueous zinc chemistry designed for about 10 hours of discharge to extend solar output well beyond daylight hours while lithium-ion units provide shorter, faster response.
- MN8 will own and operate the facility on a reclaimed coal-mine site in Kanawha County and estimates the build could total up to $350 million in capital, create roughly 200 construction jobs, and deliver about $4 million in property taxes over the first 20 years.
- Company-provided timing puts the solar plant in service in 2028, the lithium-ion batteries in 2029, and the Eos Z3 system in 2030, but those dates are estimates that depend on permitting, construction and execution.
- Eos stock jumped in reaction to the announcement, giving the company a market boost while analysts and filings note persistent financial pressure from Q2 losses and a narrowed 2026 revenue outlook that leave delivery risks for its manufacturing-consolidation plan.