The U.S. has broken ground on a 1.2 GW solar farm at an active coal mine, with Panamint Capital investing $1.7 billion in the project that will make it the largest solar installation at an operating coal site in North America, local media reported on July 28.

The Big Rooter Power development at the Twin Oaks power station in Robertson County will be built alongside an existing 310-MW lignite-fired plant that will remain in service, with no retirement plans announced.

The solar farm will be developed in two phases. Big Rooter West, a 491-MW facility, has started construction and is expected to begin operations in August 2028. Big Rooter East, at 658 MW, is scheduled to break ground in December 2026 and enter commercial service by August 2029.

Panamint estimates that the roughly 10,000-acre complex will host nearly 1.5 GW of combined coal and solar generation, along with over 20 miles of new 345-kV transmission lines, 1.6 GW-hours of battery storage, and infrastructure for up to 790 MW of data center capacity.

The U.S. leading solar technology company First Solar will supply around 2 million panels from its Ohio, Louisiana and Alabama factories, while SOLV Energy has been selected to oversee engineering, procurement and construction. The project will also require more than 34,000 tonnes of U.S.-made steel. Panamint has signed a long-term power purchase agreement with an undisclosed investment-grade offtaker that runs into the 2050s.

The project comes as Texas faces rising electricity demand driven by data center growth, with the Dallas-Fort Worth region among the fastest-growing markets. JLL's latest outlook identifies power availability on the ERCOT grid as a major constraint on further data center expansion across the state.