FLORENCE, AZ — The Florence Town Council on June 16 unanimously approved a land use change for the Copper Crossing energy storage research site in northern Florence, just south of San Tan Valley. The vote advances SRP’s plans for non-lithium battery research on 33.546 acres of land it owns.
The Copper Crossing energy storage decision principally affects ESS Tech’s planned battery pilot and space for future research projects. Salt River Project’s (SRP) first planned pilot, CMBlu Energy’s Desert Blume, was already allowed under the existing zoning and is in site-plan review. Together the two pilots are designed to store enough energy to power about 2,250 average homes for 10 hours.
Council Clears Industrial Designation for the Battery Site
The action relabels the 33.546 acres in the town’s long-range land use plan, moving the parcel from a residential category to an industrial one that fits energy facilities like battery storage. The Planning and Zoning Commission voted 4-0 on May 21 to recommend the change.
The site is part of the larger Copper Crossing Energy and Research Center, which also includes solar generation and gas turbines on adjacent SRP land.
Two Non-Lithium Pilots Anchor Copper Crossing Energy Storage
Two long-duration energy storage (LDES) pilots anchor the research site. Each is a 5-megawatt, 10-hour-duration project. The application and the battery manufacturers cite several advantages of the non-lithium chemistries over lithium-ion batteries: longer storage windows, reduced fire risk, supply chains that avoid lithium, cobalt, and other rare metals, and components that are largely recyclable at end of life.
CMBlu Energy’s Desert Blume will use Organic SolidFlow battery technology. The system relies on a non-flammable mixture of solids and water-based electrolytes housed inside buildings. According to the application, CMBlu expects its batteries to cost-effectively store and deliver energy two to three times longer per cycle than lithium-ion technology, which typically targets a four-hour duration.
ESS Tech, Inc.’s Project New Horizon will use iron flow battery technology. Reese Anderson, the Pew & Lake attorney representing SRP, described it to the council as “a mixture of salt, iron, and water.” Furthermore, the non-flammable Energy Base system is designed to deliver 10 hours of discharge, with charging in 10 hours or less.
Both companies will build, own, and operate the batteries on land leased from SRP. The pilots will store energy during daytime solar-generation hours and release it to the grid at night, when customer demand stays high but solar generation falls off.
Three Potential Future Project Areas on the Parcel
Councilmember Tony Bencina asked Anderson to clarify a related request to raise the building height from 30 to 40 feet that will appear in the upcoming zoning case. He wanted to know whether the taller structures would be office buildings.
Anderson explained that the additional height would accommodate research equipment, including water towers for fire suppression. He then pointed to three potential future project areas on the parcel beyond CMBlu and ESS, labeled three, four, and five. SRP has not yet issued requests for proposals for those future sites. “We’re really trying to set the stage and the parameters for these future projects,” he said.
Why SRP Came to the Town at All
Anderson opened his presentation by explaining why SRP appeared before the council in the first place. As a political subdivision of the State of Arizona, the utility usually does not seek local permission for projects on its own land.
However, the agency chose to follow the local process for this parcel because it plans to lease the land to outside operators. “Where they are going to lease to a third party that’s a private operator, they’ve made a policy decision to work with the local authorities on getting land use entitlements and permits,” Anderson said.
Vice-Mayor Adam Praises Transparency, Flags Safety Unknowns
Vice-Mayor Cathy Adam thanked SRP for bringing the project to the council early. “This is about as transparent as you can be,” she said. “These are future plans. They’re letting us know way in advance.”
At the same time, she voiced caution about the unknowns of the new chemistry. “I’m very, very supportive that SRP is trying these new technologies. I love that it’s in Florence,” Adam said. “But flip side of that is it’s new, we don’t know what the issues are. We don’t know how dangerous it is.”
In closing, she urged residents to track upcoming Planning and Zoning Commission meetings. “Everybody who’s interested in battery storage, solar, whatever, please pay attention to the planning and zoning calendar,” she said. “Because it’s going to go there first, before it comes to council, so there’s plenty of time to understand, ask the questions.”
Mayor Eaton Praises 2024 Codes, Criticizes State
Mayor Eaton praised SRP for engaging the town voluntarily. At the same time, he accused state lawmakers of taking away public comment and public input. “What we’ve got taken away from us lately from our state legislators, who apparently are more smart than we are, is the public comment and the public input,” Eaton said.
He also highlighted Florence’s recent adoption of updated 2024 codes. Staff documents say both projects plan to build to the 2024 International Fire Codes. “We finally were able to do something proactive and we adopted the 2024 codes that apply to this,” Eaton said. “Your submittals will now be under the new codes.”
According to the staff report, ESS met with the Town Fire Marshal in a pre-application meeting. The company pledged to help train Florence Fire Department personnel on firefighting practices for the battery systems.
Zoning Case Returns Within Two Months
A follow-up zoning case tied to the Copper Crossing energy storage site is expected to return to the Planning and Zoning Commission and Town Council within roughly one and a half to two months, Anderson told the council. The case will seek to expand the project’s existing zoning by about 26.66 acres and raise the height limit Anderson described, and will require new public hearings before both bodies.
