The Big Rooter solar project in Robertson, Texas is set to add 1.2 gigawatts of solar capacity to the state’s grid at a cost of $1.7 billion, with energy investment firm Panamint using the existing infrastructure of a neighbouring coal plant to cut both cost and construction time.
The project sits adjacent to the Twin Oaks coal-fired plant, a placement that Panamint CEO Apolka Totth described as being made ‘with the express intention of leveraging the site’s existing characteristics to massively and rapidly expand generating capability at the lowest possible cost’, in an email to Canary Media. That infrastructure, which would cost tens of millions of dollars to replicate from scratch, includes grid connection points, transmission equipment, and site access that would otherwise require years of permitting and capital expenditure.
Two Phases, One of the Largest Solar Builds in the Country
Big Rooter will be delivered in stages. The first phase is already under construction, with 491 megawatts of solar panels scheduled to come online in August 2028. According to BIC Magazine, the second phase, known as Big Rooter East and rated at 658 MWdc, is expected to break ground in December 2026, with commercial operation targeted for August 2029.
Together, the two phases will be paired with 1.6 GW of battery storage and 20 miles of new high-transmission power lines. Long lead-time components, including transformers and circuit breakers, have already been ordered. The project is believed to qualify for a federal investment tax credit worth 50% of its total costs, a financial cushion that helps explain the pace at which procurement has moved.
‘We believe deploying new capacity at existing energy sites is the clearest way to benefit communities, ratepayers, and the environment alike,’ Totth said.
The Big Rooter Solar Project and the Brownfields Approach
The strategy Panamint is pursuing belongs to a wider shift in how the United States develops clean energy. Brownfields development, which means building on land already converted for extractive or industrial use, is substantially cheaper than breaking ground on undeveloped greenfield sites. Canary Media recently catalogued similar projects in Illinois, Kentucky, and Louisiana, all built on or planned for reclaimed mine land.
Robertson, Texas fits the pattern: the Twin Oaks site already carries decades of industrial footprint. Rather than remediate and walk away, Panamint is using what is already there to wire in solar at scale.
Texas provides useful context for how large ‘at scale’ can get. The state accounts for 30% of national wind energy production, and its installed solar capacity, while not yet leading the country, sits close to California’s 55 installed gigawatts. Big Rooter, once complete, would rank among the largest solar installations in the United States.
The Complication: Twin Oaks Is Not Closing
The project is not without tension. Panamint, which is backed by investment fund KKR, has no current plans to shut the Twin Oaks coal plant. More than that, the company is investigating expanding both the plant and the associated mine, part of a broader strategy of extracting value from ageing fossil fuel assets while simultaneously building large-scale solar and wind capacity.
That dual approach will sit uneasily with some. Using coal infrastructure as a bridge to renewables is one thing; continuing to operate and potentially grow the coal side is another. Totth has not publicly addressed how long Twin Oaks is expected to remain active alongside its solar neighbour.
Construction on Big Rooter’s first phase is already under way, with the August 2028 target for the initial 491 MW now driving procurement and site work.
