MN8 Energy, Google, and Eos Energy Enterprises have announced a three-way collaboration to deliver clean, around-the-clock energy resources to the PJM grid in West Virginia, combining utility-scale solar power with two distinct battery storage technologies in what will be the first commercial-scale long-duration energy storage deployment in the state.

Project Overview and Technology Mix

The project, called Mammoth Solar, is located in Kanawha County, West Virginia, and is owned and operated by MN8 Energy.

It integrates 86 megawatts of utility-scale solar generation with 70 MW of lithium-ion energy storage providing 280 megawatt-hours of capacity, and 10 MW of Eos Energy's Z3 zinc-based long-duration energy storage system providing 100 megawatt-hours of capacity.

The zinc-based system is designed to deliver 10 hours of storage duration, extending the availability of solar generation beyond what the shorter-duration lithium-ion system alone could provide.

MN8 custom-designed the integrated portfolio to convert intermittent renewable generation into a single, dispatchable resource matched to data center load profiles.

The solar project is expected to reach commercial operation in 2028, with the lithium-ion storage following in 2029 and the long-duration storage system coming online in 2030.

Google's Role and Energy Commitments

Under the terms of the agreement, Google will purchase the energy, capacity, and clean energy attributes of the entire project.

The project is intended to serve Google's data centers in the PJM region, including a planned facility in West Virginia.

Google described the collaboration as part of its broader efforts to bring new capacity to the grids where it operates and to accelerate the commercialization of long-duration energy storage technology.

Lucia Tian, Director of Advanced Energy Technologies at Google, said the collaboration aims to deploy a portfolio of round-the-clock technology solutions to help power Google's digital infrastructure while creating economic benefits for West Virginia.

The company stated its intention to use projects like this to make reliable, affordable electricity available around the clock and to support grid resilience as renewable energy sources grow in scale.

Jon Yoder, President and CEO of MN8 Energy, said the project reflects MN8's approach of understanding a customer's unique energy profile and building a solution tailored to it.

He noted that Google's willingness to pair next-generation storage with utility-scale solar allowed MN8 to engineer proven and emerging technologies into one dispatchable resource.

First Deployment of Eos Z3 Technology for Google

The West Virginia project represents the first time Google has used Eos Energy's American-made Z3 technology, and it is also the first project executed under a previously announced Master Supply Agreement between MN8 and Eos.

The Z3 system relies on aqueous zinc chemistry rather than lithium-ion chemistry, and Eos manufactures its systems in Pittsburgh, Pennsylvania.

Nathan Kroeker, Chief Commercial Officer at Eos, said the company's work with Google is focused on deploying American-made long-duration storage that addresses real grid reliability challenges.

He said the Z3 system extends the value of clean generation across more hours of the day and strengthens the overall portfolio's ability to deliver dependable capacity.

The project is intended to demonstrate how Eos' zinc chemistry can support critical grid infrastructure at commercial scale.

Site History and Economic Impact

The Mammoth Solar project is being built on a reclaimed coal mine in West Virginia, a state with a long history in the energy sector.

MN8 estimates the project represents up to USD 350 million in capital investment. Over the first 20 years of operations, the project is expected to generate approximately USD 4 million in property tax revenue for Kanawha County and local schools, with additional tax revenue projected to continue in the 15 to 20 years that follow.

Construction activity associated with the project is expected to create approximately 200 jobs, with additional full- and part-time positions supporting the project throughout its operating life. MN8 did not specify a total number of permanent operating positions.

Regional Manufacturing and Grid Connections

Both MN8 and Eos maintain operations and workforces across the Mid-Atlantic and Northeast regions.

MN8 has projects spanning those areas, while Eos is headquartered and manufactures its storage systems in Pittsburgh, Pennsylvania.

The companies stated that together they support domestic supply chains and regional economies across the PJM Interconnection, which connects energy infrastructure in West Virginia with broader markets in the region.

MN8 describes itself as a scaled power platform that develops, owns, and operates energy assets. The company has more than 4 gigawatts of operating and under-construction assets across 29 states and serves more than 200 customers, including artificial intelligence and hyperscale technology companies, Fortune 500 corporations, and government agencies.