First Solar partners on 50MW solar plus Arizona’s largest battery storage project to serve APS customers

Phoenix-based Pinnacle West Capital Corp subsidiary Arizona Public Service and cadmium telluride (CdTe) thin-film photovoltaic module maker First Solar Inc of Tempe, AZ, USA say they are bringing what is claimed to be a first-of-its-kind 50MW solar-fueled battery to the desert to provide renewable energy to Arizonans on hot summer days. The project will include one of the largest battery storage systems in the USA. The design models how the future of solar and storage can work together to supply power during peak hours.

First Solar will build and operate the flagship facility, which includes a 65MW solar field to charge the battery. A 15-year power-purchase agreement with First Solar will enable APS to use the stored battery power when energy use is at its peak later in the day.

By pairing solar energy with advanced battery technology, First Solar and APS will be able to store power when the sun is high in the sky and deliver it to customers at 3-8pm when the sun is on its way down but energy use is peaking, enabling APS customers to get more of their peak power from solar.

The project adds to the more than 1 million solar panels and three grid-scale batteries currently on APS’s system. Over the next 15 years, the firm plans to adopt more than 500MW of additional battery storage.

“Partnering with an Arizona company such as First Solar to pair solar power with advanced battery storage is good for our customers and continues our state’s national leadership in clean energy innovation,” says APS’ chairman, president & CEO Don Brandt.

For First Solar, the addition of battery storage to utility-scale solar allows the sun’s power to be used in the evening when the energy is needed most (logical use of technology in a state that sees nearly 300 days of sunshine per year).

The project was developed in response to APS’s request for peaking capacity resources to serve customers between the peak hours of 3-8pm during the hot summer months. APS has full use of the 50MW battery and is able to maximize hourly capacity until it is fully discharged. The facility is set to begin service to customers in 2021 and will be built directly adjacent to the existing APS Redhawk Power Plant in western Maricopa County.