APS, First Solar Partner on Arizona’s Largest Battery Storage Project

50-MW solar plus storage facility will serve APS customers during hot summer months

PHOENIX — Two homegrown leaders in renewable energy, Arizona Public Service and First Solar (Nasdaq: FSLR), are bringing a first-of-its-kind 50-megawatt (MW) solar-fueled battery to the desert to provide clean power to Arizonans on hot summer days. This project will make Arizona home to one of the largest battery storage systems in the country. The innovative design models how the future of solar and storage can work together to deliver power to customers during peak hours.

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

By pairing clean 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 between 3 and 8 p.m. when the sun is on its way down, but energy use is peaking. This means that APS customers can get more of their peak power from solar.

Arizonans want clean and reliable energy. This project adds to the more than one million solar panels and three grid-scale batteries currently on APS’s system. Over the next 15 years, APS plans to adopt more than 500 MW 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,” said Don Brandt, Chairman, President and CEO of APS.

For First Solar, the project represents the next step in solar energy. Utility-scale solar is a clean energy resource, and the addition of battery storage allows the power of the sun to be used in the evening when the energy is needed most. This is a logical use of technology in a state that sees nearly 300 days of sunshine per year.

“First Solar has long been a global leader in the deployment of utility-scale solar,” said Mark Widmar, First Solar’s Chief Executive Officer. “Through this innovative project we are excited to partner with APS to demonstrate the capabilities of solar coupled with large-scale battery storage. Together, these technologies highlight the significant role for solar in providing reliable, cost effective energy.”

The project was developed in response to APS’s request for peaking capacity resources to serve customers between the peak hours of 3 and 8 p.m. during the hot summer months. APS has full use of the 50-MW 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.

Arizona has always been a state powered by the sun. Whether it is growing cotton and citrus or an enviable climate, the sun is at the center of Arizona’s economy. With this project, APS and First Solar will continue that tradition.

About APS
APS serves about 2.7 million people in 11 of Arizona’s 15 counties, and is the Southwest’s foremost producer of clean safe and reliable electricity. Using a balanced energy mix that is nearly 50 percent carbon-free, APS has one of the country’s most substantial renewable energy portfolios, and owns and operates the Palo Verde Generating Station, the country’s top power producer and largest producer of carbon-free energy. The company is also a proven leader in introducing technology and services that offer customers choice and control over their energy consumption. With headquarters in Phoenix, APS is the principal subsidiary of Pinnacle West Capital Corp. (NYSE: PNW).

About First Solar, Inc.
First Solar is a leading global provider of comprehensive photovoltaic (PV) solar systems which use its advanced module and system technology. The company’s integrated power plant solutions deliver an economically attractive alternative to fossil-fuel electricity generation today. From raw material sourcing through end-of-life module recycling, First Solar’s renewable energy systems protect and enhance the environment. For more information about First Solar, please visit www.firstsolar.com.

Forward-Looking Statements
This release contains forward-looking statements which are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These forward-looking statements include statements, among other things, concerning the construction and operation of a 50MW solar-fueled battery by First Solar. These forward-looking statements are often identified by words such as “estimate,” “predict,” “may,” “believe,” “plan,” “expect,” “require,” “intend,” “assume” and similar words. Forward-looking statements are only predictions based on our current expectations and our projections about future events so you should not place undue reliance on these forward-looking statements. A number of known and unknown factors could cause future results, levels of activity, performance or achievements to differ materially from those expressed or implied by these statements. Discussions of some of these factors are contained in the “Risk Factors” and related sections of Pinnacle West’s and First Solar’s most recent Annual Reports on Form 10-K and their respective other periodic filings with the Securities Exchange Commission, which we urge you to review carefully. We assume no obligation to update any forward-looking statements, even if our internal expectations and projections change, except as may be required by applicable law.