Google, MN8 Energy and Eos are pairing solar, lithium-ion and zinc-based long-duration storage at a West Virginia site to power its data centers, offering a cleaner alternative to the diesel generators fueling pushback elsewhere.
In sum – what to know:
A three-way clean power deal – MN8, Google and Eos are building an 86MW solar, 70MW/280MWh lithium-ion and 10MW/100MWh zinc-based LDES facility in West Virginia, coming online in 2028-30, to power Google’s regional data centers.
Grid strain is forcing the issue – PJM, which manages the grid across 13 states, is 6.8GW short on capacity and has proposed a framework requiring data centers without their own power supply to curtail consumption or draw on backup resources during emergencies.
A cleaner alternative to diesel – Where Amazon and Duke Energy turned to hundreds of backup generators at their Hamlet, NC site, Google is betting on storage-plus-renewables as a way to add dispatchable capacity without the community and environmental fallout.
With grid networks coming under increasing strain from data center demand, hyperscalers are exploring all possible options to get their sites up and running. For Amazon and its utility partner Duke Energy, that meant looking at diesel generators for its Hamlet, NC facility. Google is taking a different path, having announced in early September the Mammoth joint solar and lithium-ion storage project in West Virginia, in partnership with MN8 Energy and Eos Energy Enterprises. The facility, which is set to come on stream through 2028-30, will combine around 86MW of utility-scale solar, with lithium-ion energy storage totalling 70MW/280MWh and zinc-based long-duration energy storage (LDES) offering 10MW/100MWh of capacity.
Pairing short and long-duration storage
The project represents the first deployment of LDES in West Virginia, pairing short and long-duration storage into an integrated renewable energy system. MN8 will own and operate the facility, with Google purchasing the energy and capacity to power its data centers in the region. With the 10MW/100MWh Eos system designed to provide up to ten hours of storage, the facility will deliver clean and dependable capacity at a time of mounting grid accessibility challenges across the US.
Moe Hanifi, Head of Revenue & Commodities at MN8, said the strength of this particular storage architecture lies in the combination of low-cost solar with both short-duration and long-duration storage, which provides added reliability and flexibility when compared with the use of any of these technologies in isolation. Another crucial benefit, he added is the use of lithium-ion batteries, which “shift solar energy into higher-demand hours, while long-duration storage can sustain output over longer periods and provide additional reliability value during extended grid stress events.”
Hanifi believes this combined renewables and storage arrangement is likely to become more commonplace in future. “We’re seeing an evolution in how these customers [hyperscalers] think about energy procurement,” he said. “It’s no longer only about purchasing renewable energy. Increasingly, they’re looking for solutions that can add new generation and provide dependable capacity in the regions where their facilities operate. Projects like Mammoth are a reflection of that shift.”
No winner-takes-all
For Google, Mammoth reflects a broader long-duration storage strategy rather than a one-off move. The company has previously backed LDES deployments using different technologies, including CO2-based storage with the Salt River Project in Arizona. “We think of storage on a spectrum,” a Google spokesperson said. Lithium-ion batteries remain central to that mix, but its economic dispatch tops out around eight hours. Beyond that, the company says, different chemistries are needed, which is where technologies like Eos’ zinc-based system come in. Notably, Google is careful not to frame this as a bet on one singular technology. “In each technology category, including LDES, we believe there is no winner-take-all,” the spokesperson said, adding that it sees LDES as a near-term solution to help global electricity systems grow more flexibly, cleanly and reliably.
Backstop arrangement
Just as important as the technology mix itself is the geographic market in which Mammoth solar operates. The project falls under the purview of PJM Interconnection, which manages the grid across 13 Mid-Atlantic and Midwest states and Washington DC. The operator has repeatedly flagged capacity shortfalls as data center demand climbs. Facing a 6.8GW reliability shortfall from its most recent capacity auction, PJM proposed a backstop arrangement in July to close the gap. In mid-August, it followed with a separate framework that would require data centers without their own power supply to curtail consumption or draw on backup resources when the grid nears emergency conditions.
As Amazon has found with its project in Hamlet, NC, leaning on generators can put operators on a collision course with the communities living alongside them. That makes combined renewables-storage projects like Mammoth an increasingly attractive proposition, as they provide clean and dispatchable supply in that market rather than just offsetting data center-related emissions. In addition, LDES systems like Eos’ zinc-based Z3 are built to discharge energy over a period of hours, unlike shorter-duration lithium-ion batteries that discharge in a matter of minutes. This makes these systems better suited to covering prolonged grid stress events, which is precisely the scenario that is of concern to utilities as AI-driven demand strains aging infrastructure.
