Google backs solar-storage project at former West Virginia coal mine

Google is buying power from a new solar-and-storage project planned for the site of a former coal mine in Kanawha County, West Virginia. The project, called Mammoth Solar, will pair 86 megawatts of solar panels with two kinds of battery storage: 70 MW/280 megawatt-hours of standard lithium-ion batteries and 10 MW/100 megawatt-hours of zinc-based batteries, a newer, nonflammable technology that can discharge power for more than eight hours at a stretch. The solar portion is set to start operating in 2028, with the batteries following in 2029 and 2030. The developer is MN8, and the zinc batteries come from Eos Energy Enterprises.

This is a large-scale grid project, not something tied to any home upgrade or rebate program. Google says the power will help meet demand from its data centers in the region, and the companies note it will also add capacity to the PJM grid, which covers much of the mid-Atlantic and parts of the Midwest and has recently faced tight supply and high costs at electricity auctions. For homeowners in that grid region, more power capacity coming online, especially storage that can run for many hours, is one factor that can help keep the grid stable during high-demand periods.

Google has a similar, even larger project underway in Minnesota, a battery installation paired with a data center there. Both are part of the company's broader push to line up clean power sources near its data centers rather than any program aimed at residential energy use.