APS, First Solar to install Arizona’s largest battery system

Arizona Public Service is partnering with First Solar to provide a 50 MW, 135 megawatt-hour (MWh) battery storage project to the state.

The module manufacturer, whose headquarters are in Arizona, will construct a 65 MW solar farm to charge the battery. The state’s largest utility has signed a 15-year power-purchase agreement to buy the stored electricity to use mid-day electricity to meet peak afternoon demand, which APS says is between 3 p.m. and 8 p.m. in its service territory.

50 MW is one of the largest battery projects to date in the United States, and will be the largest single-site battery project in Arizona.

Under its long-term solar plans, APS says it will add at least 500 MW of battery storage over the next 15 years in addition to the First Solar project.

“Through this innovative project, we are excited to partner with APS to demonstrate the capabilities of solar coupled with large-scale battery storage,” said Mark Widmar, First Solar’s CEO. “Together, these technologies highlight the significant role for solar in providing reliable, cost effective energy.”

The project is expected to be completed by 2021 and will be built directly adjacent to the existing APS Redhawk Power Plant in western Maricopa County.