US electric company Southern Power has started commercial operations at the 180MW second phase of its Millers Branch Solar Facility in Haskell County, Texas.
The second phase is marginally smaller than the first phase of the project—which stands at 200MW—and was announced by Southern Power in 2024 following its acquisition of the Millers Branch project from EDF Renewables. The successful completion of construction work and start of commercial operations at the second phase is in line with Southern Power’s initial timeline for the project, and the phase is notable for the multi-party offtake deal that has been signed to acquire renewable energy credits generated by the project.
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Southern Power has signed a series of virtual power purchase agreements (VPPAs) with seven buyers for the project’s output. These include Cisco (which will acquire certificates generated by a 50MW portion of the project); Juniper Networks (40MW), Bio-Rad Laboratories, Cadence and IDEXX Laboratories (20MW); and PTC (10MW). A further unnamed “large healthcare company” was also identified as offtaker for the remaining 20MW of capacity.
This multi-buyer approach was coordinated by the Sustainability Roundtable, a US-based platform that aims to facilitate such deals through its ‘Net Zero Consortium for Buyers’ (NZCB) structure. Southern Power has already signed an offtake agreement for the third phase of the Millers Branch project, with a capacity of 132MW, which also uses the NZCB structure, with Synopsys and Keysight signing VPPAs for the project’s output.
Sustainability Roundtable notes that its NZCB structure has facilitated deals for 1GW of renewable energy capacity and plans to add another gigawatt of capacity in the coming years.
The news follows a number of advancements in the massive Texas solar PV sector, including the completion of construction work at a phase of Origis Energy’s 2GW solar-plus-storage project in the state, and the signing of a plethora of more conventional PPAs. Among the offtakers are tech giants Tesla, Meta and Microsoft.

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