Sian Crampsie

Arizona Public Service (APS) says it will be able to maximize its use of solar energy through a new programme for the roll-out of large-scale battery-based energy storage plants.

The US utility says it will install 850 MW of battery storage and at least 100 MW of new solar generation by 2025.

The battery storage will be added to APS’ existing fleet of solar energy plants as well as new solar capacity, and will help to ensure that it can deliver clean energy to customers at times of peak energy usage, as well as when the sun has set.

“Arizona is already a national leader in solar energy. The challenge is, no one has figured out how to stop the sun from setting at night,” said APS Chairman and CEO Don Brandt. “As storage technology improves and declines in cost, we will increasingly be able to store the power of the sun cost-effectively to deliver when our customers need it.”

APS’ plans were welcomed by the Energy Storage Association (ESA). “We especially applaud APS for partnering with third parties in this effort, sending a strong signal for businesses to invest in energy storage in Arizona,” said Kelly Speakes-Backman, CEO of ESA. “We look forward to that day when energy storage is the central tool for maintaining a reliable and resilient, efficient, sustainable and affordable grid.”

APS owns and operates large-scale solar plants throughout Arizona that will be upgraded with 200 MW of battery storage systems. A team led by Invenergy will install six of the new battery systems at solar plants in Maricopa County and Yuma to be in place by 2020. The remaining two upgrades will be completed by 2021.

APS plans to build an additional 500 MW of solar storage and stand-alone battery storage by 2025. The first project will be a 100 MW solar-storage plant for which APS expects to issue a request for proposals this summer.

APS is already partnering with First Solar to build a first-of-its-kind solar-plus-storage project that will be one of the largest in the USA when completed in 2021.