Google has partnered with US clean energy developer MN8 Energy and long-duration battery storage firm Eos Energy to develop a solar-plus-battery project in Kanawha County, West Virginia.

The deal will support the development of the Mammoth Solar project, which combines 86MW of utility-scale solar, 10MW/100MWh of Eos’ Z3 zinc-based long-duration energy storage, and 70MW/280MWh of lithium-ion energy storage. The project is being constructed on a reclaimed coal mine in West Virginia.

“This project reflects what MN8 does best: understanding a customer’s unique energy profile and building a solution around it,” said Jon Yoder, president and CEO of MN8 Energy. “Because Google was willing to pair next-generation storage with utility-scale solar, we could engineer proven and emerging technologies into one dispatchable resource – and deliver clean, around-the-clock power where the grid needs it most.”

The project will deliver power to the PJM Interconnection and support Google’s data centers in the region, including a planned project in West Virginia.

According to the companies, the solar project will reach completion in 2028, with the lithium-ion storage and long-duration storage following in 2029 and 2030, respectively. The partners claim the project's multi-technology solution will match data centers' load profile. When completed, it will be the first long-duration storage project in West Virginia.

“At Google, we’re committed to backing solutions that both serve our data center capacity needs and accelerate progress toward cleaner, more affordable energy systems,” said Lucia Tian, director of advanced energy technologies at Google. “This collaboration with MN8 and Eos aims to deploy a smart portfolio of round-the-clock technology solutions to help power our digital infrastructure, while creating meaningful economic benefits for West Virginia.”

Under the terms of the deal, Google will purchase the project's energy, capacity, and clean energy attributes. The hyperscaler said it forms part of its broader efforts to commercialize long-duration electricity storage (LDES) technology. The company has partnered with Italian LDES firm Energy Dome, with the companies' first project expected to come online in 2028.

The deal also represents the first joint project under the previously announced MN8-Eos Master Supply Agreement. The deal, signed in October of last year, seeks to deploy up to 750MWh of LDES systems across renewable energy projects across the US.

“The grid needs more from every megawatt of new generation,” said Nathan Kroeker, CCO at Eos. “Our work with Google is focused on deploying American-made long-duration storage where it solves real grid reliability challenges. Z3 extends the value of clean generation across more hours, strengthens the overall portfolio, and delivers more dependable capacity when it’s needed most.”

Based out of Edison, New Jersey, Eos is a BESS manufacturer specializing in zinc-based energy storage. Its flagship Znyth storage system is a long-duration battery designed for four to 16 hours of duration with a 25-year total lifespan. According to the company, it has several active commercial deployments across the US. The deal with Turbine-X would be the largest deployment to date.

MN8 Energy is an independent renewable and battery energy storage developer. The company has approximately 4GW of operational and under-construction solar projects as well as around 1.1GWh of battery storage. Earlier this year, the company signed an 80MW Power Purchase Agreement with Meta tied to a solar project in Juniata County, Pennsylvania.