NRG Energy, Tucson Electric Power (TEP) and First Solar celebrated the completion of the 25-megawatt (MW) Avra Valley Solar Generating Station near Tucson, Ariz. on Dec. 13. The project was developed and is owned by NRG Energy, and the electricity will be sold to Tucson Electric Power under a 20-year power purchase agreement, making it the single largest PV system in TEP’s renewable energy portfolio. First Solar designed and constructed the power plant using its trackers and 410,000 of its Series 3 thin-film PV modules, and it will provide Operations and Maintenance (O&M) services for the facility.