Panamint Capital is developing the US$1.7 billion Big Rooter Power project in Robertson County, Texas, United States. The 1.2GW solar photovoltaic development is being built at the company’s Twin Oaks power station site, approximately halfway between Dallas and Houston. Once completed, it is expected to become North America’s largest solar project constructed on an existing coal mining site.
Construction officially began on July 23, 2026. The development will be delivered in two phases: Big Rooter West and Big Rooter East. The first phase will provide 491MWdc of solar generation capacity. The second phase will add a further 658MWdc. Together, the phases represent approximately 1,149MWdc, with the project marketed at approximately 1.2GWdc.
The development will transform part of an established energy and mining site into a combined power and digital infrastructure hub. Additionally, it will use existing infrastructure to support new electricity generation and reduce the need to develop an entirely new energy site.
Construction Programme and Project Phases
Construction is underway on Big Rooter West, the first phase of the development. The 491MWdc facility is scheduled to begin commercial operations in August 2028. Meanwhile, construction of Big Rooter East, which will deliver 658MWdc, is expected to begin in December 2026. Its commercial operation is targeted for August 2029.
The two phases will be developed on land within the Twin Oaks energy complex. Furthermore, the wider site spans approximately 10,000 acres and already hosts conventional power generation and mining-related infrastructure.
Furthermore, the development will retain the wider site’s existing thermal generation operations. Panamint plans to integrate solar generation, battery storage and data centre infrastructure into the broader energy complex.
Solar Panels and Construction Materials
First Solar has been selected to manufacture approximately two million solar panels for the two phases. The panels will be produced at its manufacturing facilities in Ohio, Louisiana and Alabama. Consequently, the project will use domestically manufactured photovoltaic equipment.
Nextpower will supply its NX Horizon solar tracker systems. The installation will also incorporate Hail Pro-75 and NX Navigator software. These technologies are intended to improve solar panel positioning, operational monitoring and performance under different weather conditions.
The construction programme will also use more than 34,000 tones of domestically manufactured steel. This material will support the project’s structural and associated infrastructure requirements. In addition, the development will require electrical equipment, substations, transmission connections and supporting civil works.
Battery Storage and Wider Energy Infrastructure
In addition to solar generation, the Twin Oaks site is planned to accommodate substantial battery energy storage infrastructure. Panamint Capital’s portfolio identifies two developments: Big Rooter Storage West and Big Rooter Storage East. Each will provide 200 MW of battery power and 800 MWh of storage capacity. Consequently, the two projects will deliver a combined 400 MW and 1.6 GWh of storage, with commercial operations expected in 2028 and 2029, respectively.
The wider energy complex is also expected to incorporate more than 20 miles of new 345kV transmission infrastructure. Additionally, Panamint has identified approximately 790MW of data centre capacity under development at the site. These investments are intended to connect electricity generation, storage and digital infrastructure within one energy campus. 
Engineering, Procurement and Construction
Panamint Capital selected SOLV Energy as the engineering, procurement and construction (EPC) contractor. Its responsibilities include delivering the solar facilities, substations and transmission infrastructure. The contractor will also support project delivery and long-term asset performance.
The Big Rooter Power project will use Nextpower’s solar tracking technology and First Solar’s photovoltaic modules. Meanwhile, the use of locally manufactured steel and solar equipment supports the project’s domestic supply-chain strategy.
Project Financing and Economic Impact
The overall Big Rooter Power project carries an estimated investment of US$1.7 billion. The two phases are expected to create more than 800 construction jobs. Furthermore, Panamint estimates that Big Rooter West alone will contribute more than US$66 million to the local economy over its lifetime.
The developer is also prioritising local recruitment and regional suppliers. Its long-term power purchase agreement with an investment-grade electricity buyer is expected to provide revenue certainty for the solar development. However, the buyer has not been identified.
Project Significance
Big Rooter Power Project represents the redevelopment of an established energy and mining location. Rather than developing an entirely new site, Panamint is using existing land and infrastructure at Twin Oaks and the Calvert Mine.
Consequently, the project demonstrates how former fossil-fuel sites can accommodate new renewable generation, battery storage and electricity-intensive industries. It also adds generation capacity in Texas, where electricity demand is increasing.Texas is also addressing rising electricity demand through a proposed nuclear and natural gas power plant by Blue Energy and GE Vernova, complementing the Big Rooter solar and battery storage development.
Once operational, the wider Twin Oaks complex will combine conventional generation, solar power, battery storage, transmission infrastructure and data centre development. This integrated approach could provide a model for converting legacy energy sites into multi-purpose electricity and digital infrastructure hubs.
Big Rooter Power Project Fact Sheet
Project: Big Rooter Power
Location: Twin Oaks power station, Robertson County, Texas, USA
Developer: Panamint Capital
Project type: Utility-scale solar photovoltaic development
Estimated investment: US$1.7 billion
Announced capacity: Approximately 1.2GWdc
Developer portfolio capacity: 1,170MW
First phase: Big Rooter West ( 491MWdc)
Second phase: Big Rooter East (658MWdc)
Battery storage: 400MW / 1.6GWh across two facilities
Construction commencement: July 23, 2026
First phase completion target: August 2028
Second phase completion target: August 2029
Solar panels: Approximately 2 million
Construction materials: More than 34,000 tonnes of US-manufactured steel
Transmission infrastructure: More than 20 miles of new 345kV lines
Expected construction jobs: More than 800
Project purpose: Renewable electricity generation, energy storage and support for digital infrastructure.
Big Rooter Power Project Team
Panamint Capital: Project developer and investor.
SOLV Energy: Engineering, procurement and construction contractor.
First Solar: Solar photovoltaic module manufacturer and supplier.
Nextpower: Solar tracking technology and software supplier.
Twin Oaks Power Station: Existing energy infrastructure and host site.
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