This piece was originally published in the Arizona Central on January 30, 2024 and can be accessed here.
How Arizona sends solar power to your light switch, long after the sun goes down
By Andy Tobin
Markets that have more choice and competition are better for consumers.
The energy market is no different.
In the past, our choices were mostly limited to a handful of fuels — coal, oil, natural gas, nuclear and hydroelectricity.
But the falling cost of renewable electricity — a roughly 60% to 80% reduction, in the case of wind and solar — has given power companies and consumers more options to choose from.
Now, another technology is entering the marketplace — the battery energy storage system — and Arizona is playing a leading role in its wider adoption.
Batteries store electricity from solar panels
In Arizona, batteries can store electricity generated by solar panels in the middle of the day until times of peak demand in the late afternoon and evening. Just as the cost of solar-powered electricity has fallen, so has the cost of batteries — by around 80% over the past decade, in fact.
With even greater cost reductions predicted in the coming years, there’s been a surge of interest in battery energy storage projects in Arizona, especially those built alongside large-scale solar facilities.
Utilities are building numerous projects, and they have also reached agreements with private energy storage developers to dramatically scale up battery energy storage capacity in the greater Phoenix area.
Utility initiatives have played a primary role in driving the advancement of the state’s energy storage marketplace, surpassing the influence of government policies.
Most recently in Coolidge, Salt River Project (SRP) cut the ribbon on their largest battery energy storage project yet. The new Saint Energy Storage II project, developed and operated by NextEra Energy Resources for SRP, adds a 100-megawatt battery energy storage system, creating enough energy to power about 22,500 homes for four hours during times of peak demand.
NextEra Energy Resources has also pursued other projects in the Phoenix area, including the $210 million Storey Energy Center in Pinal County, which pairs 88 megawatts of solar energy with 88 megawatts of battery energy storage.
The much larger, $600 million Sonoran Solar Energy Center in Buckeye combines a 260-megawatt solar array with 260 megawatts of battery energy storage, making it the largest battery energy storage project in the state.
In north central Arizona, a massive 1,200 megawatt solar and battery energy storage facility is being developed outside Flagstaff. The CO Bar Solar facility will provide electricity to Arizona Public Service and SRP.
Utilities are rapidly adopting this technology
SRP has been operating a 25-megawatt battery energy storage facility in Peoria since 2021, next door to its Agua Fria Generating Station, which produces electricity from both natural gas turbines and solar panels.
The battery facility can power approximately 5,600 residential homes and enhances grid reliability by storing excess energy during low-demand periods and supplying it during peak hours, reducing costs while meeting customer demands.
In Avondale, SRP is working with Plus Power to build the Sierra Estrella Energy Storage facility, a 250-megawatt battery installation.
Battery energy storage projects are also being pursued in southern Arizona as well.
Tucson Electric Power is planning a $294 million 200-megawatt battery energy storage facility — the Roadrunner Reserve System — with enough capacity to power 42,000 homes for four hours during peak evening usage times.
And in Cochise County, Arizona Electric Power Cooperative recently announced plans for close to 300 megawatts of battery energy storage to be built alongside the existing Apache power station.
It stabilizes the grid, keeps power affordable
This isn’t meant to be an exhaustive list of all the battery energy storage projects that are either in service or being pursued in Arizona today.
In fact, so much is happening in this area, it’s hard to keep up.
But it’s crystal clear that battery energy storage is rapidly expanding in Arizona, which will benefit the stability of our power grid and allow the state to make even more cost-effective use of its natural resources.
Put another way, thanks to energy storage, you’ll still be able to use solar power after the sun goes down in Arizona. That’s quite an accomplishment, not to mention a victory for consumer choice.
Andy Tobin is former speaker of the Arizona House and a former member of the Arizona Corporation Commission. He is president and owner of Tobin Business Solutions LLC, and director of The Western Way’s Arizona Rural Energy Network. Reach him atandy@tobinbusinesssolutions.com.