The third phase of Copper Mountain Solar, or Copper Mountain Solar 3 got underway earlier this week, according to ClimateProgress. The project is the third, and largest, phase of Sempra U.S. Gas & Power’s Copper Mountain solar project. And is reputed to be the single largest polysilicon PV project in the world, according to project module supplier Trina Solar.

Each phase of the project has gotten larger. The first phase of Copper Mountain was a 58 megawatt installation completed in December 2010. The second phase is a 150 megawatt project. “The first 92 MW of solar panels at Copper Mountain Solar 2 were installed in late 2013, with the remaining 58 MW expected to be completed by 2015,” Sempra said. The third project, on which construction recently began, is a 250 megawatt project. The first two phases are under power-purchase agreements with Pacific Gas & Electric. The third is under a PPA with Los Angeles Department of Water and Power and the City of Burbank. Once all three projects are completed they will provide roughly 485 megawatts of solar energy for California.

Sempra chose AMEC to serve as the engineering and consulting firm on the project earlier in August. The company said that construction on the project has already begun and will create over 300 jobs during build-out, with 12 permanent operations positions.

Trina Solar is providing roughly 1,133,550 PV modules, which are expected to start shipping at the end of the year. "The selection of Trina Solar for this record-breaking project is a strong endorsement of our capabilities in meeting the evolving demands of our customers in a maturing market," said Mark Mendenhall, president of Trina Solar Americas. "We look forward to completing this project and powering tens of thousands of homes with clean, reliable solar power."

This is just one of the giant PV projects that Sempra is building in the U.S. Southwest. The company also is building the Mesquite Solar 1 project outside of Phoenix, Ariz. The first phase of the project, which is already underway, is 150 megawatts. The project could be up to 700 megawatts in size by the time it’s finished, according to Sempra. The company also is building out the Rosamond Solar project in California. That project is slated to start construction in 2014. However, all of the Sempra plants are slated to come completely online sometime in 2015. That’s largely inline with other giant solar projects being built in the southwest desert that are starting to come fully online this year and next year.