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APS Solar Research Illuminates Benefits for All Customers

October 21, 2018

Results helping industry deliver benefits reliably and affordably

Arizona is a national leader in solar energy, and APS is pursuing numerous opportunities to advance that leadership for the benefit of customers here and across the nation.

APS engineers are taking advantage through innovation, developing and deploying projects to understand solar’s potential for customers. They are also evaluating how solar interacts with energy storage and other advanced technologies.

Research from the award-winning APS Solar Partner program, Solar Innovation Study and APS Solar Communities program, among others, is being shared across the utility industry and with academic researchers, consumer advocacy groups and Arizona-based solar installers. The results are informing our company and the industry about how to bring the benefits of this clean, renewable resource and advanced technology to customers reliably and affordably.

APS is developing more clean energy resources, including innovations pairing solar energy and battery storage to deliver more solar when energy use peaks later in the day and after the sun goes down. The company announced one of the country's largest storage initiatives in February, which will add 850 megawatts of batter storage and at least 100 MW of new solar generation by 2025, for a total of 950 MW of new clean energy technology.  

On top of this announcement, APS is also partnering with another homegrown solar leader, Tempe-based First Solar, on another large solar-plus-storage project. First Solar will build and operate a 65-MW universal solar plant to charge the 50-MW/135-MWh battery, enabling more "solar after sunset" for customers.

Participation in the western Energy Imbalance Market, a real-time energy trading market covering eight western U.S. states and British Columbia, is also paying dividends for APS customers. It enables participating energy companies to buy and sell the lowest-cost energy when their customers need it in real time. The market also makes more efficient use of variable renewable energy like solar and wind, which leads to a cleaner energy grid and saves customers money.

APS has also built solar projects with creative, forward-thinking partners like the Phoenix Suns, Arizona Diamondbacks, Arizona State University and many others.

Solar Partner Program

  • The APS Solar Partner Program is the nation’s first utility-owned deployment of residential rooftop solar systems with advanced inverters and central wireless control.
  • About 1,600 customers added APS-owned rooftop solar to their homes and receive a $30 credit each month through the life of the 20-year program. Participants pay no upfront fees or maintenance.
  • Operators can manage the advanced inverters remotely – meaning that the solar installations can be operated like a power plant, ramping up or turning down power based on customers’ real-time energy needs.
  • APS works with the Electric Power Research Institute to gather and analyze program data, which is being shared across the industry and with academic researchers, consumer advocacy groups and Arizona-based solar installers. The research evaluates how to integrate solar onto the grid in areas with high penetrations of private rooftop solar while maintaining reliability for customers.

Solar Innovation Study

  • The Solar Innovation Study is a state-of-the-art initiative that integrates distributed energy resources such as rooftop solar, battery storage, home energy management systems, smart thermostats and multi-stage, variable-speed HVAC systems and couples them with demand-based service plans.
  • The study on 75 single-family homes in the Phoenix metro area tests ways customers can employ these resources to manage their energy use. It employs service plans with time-of-use pricing and a peak-usage charge that encourage customers to shift their energy use away from the peak demand hours of 3-8 p.m. on weekdays.
  • It also enables Arizona-based installers to learn how to install and maintain these emerging technologies in their early stages.

APS Universal Solar Plants

  • APS owns and operates 10 universal solar power plants across Arizona. They include nine plants built through the AZ Sun program that were designed and constructed by third-party solar developers, contractors and equipment providers. The AZ Sun plants contribute 170 MW of solar capacity for customers.
  • AZ Sun plants provide more solar for more customers at a lower cost than private rooftop solar. Customers also benefit from the savings created through renewable tax credits and the utility-operated solar plants.
  • The 40-MW Red Rock Solar Plant, APS’s largest universal solar power plant, is a partnership with ASU and PayPal. ASU and PayPal are reducing their carbon footprint by purchasing renewable energy from APS that is equivalent to the amount of energy Red Rock is projected to generate.
  • APS also plans to add 200 MW of battery storage to the AZ Sun solar plants and Red Rock. A team led by Invenergy will install six of the new battery systems at solar plants in Maricopa and Yuma counties by 2020, and the remaining two upgrades at solar plants in Pinal and Yavapai counties will be completed by 2021.


  • The Solana Generating Station, located outside of Gila Bend, is one of the largest thermal solar plants in the world. The facility, which covers three square miles, contributes 250 MW of energy capacity.
  • Its innovative technology uses the heat of the sun to create steam to power a traditional turbine and also allows the sun’s energy to be stored and used to generate power for up to six hours after sundown.
  • APS committed to buy 100 percent of the power output from Solana for 30 years, providing customers with clean and reliable energy, while supporting Arizona’s economy.

The current solar research programs continue APS’s dedication to solar energy innovation, which dates to the 1950s.

Categories: Clean
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