The Pinal County Board of Supervisors approved a large battery storage facility on 25 acres inside the Town of San Tan Valley, signing off on three linked land-use cases that clear the way for the Copper Basin Energy Storage project.

The site sits at the southwest corner of East Bella Vista Road and North Attaway Road, surrounded on three sides by Salt River Project (SRP) energy land, including a 270-acre solar field and a major SRP substation. The board approved all three cases as presented, each on a voice vote with no supervisors opposed.

What a Battery Storage Facility Does

A battery energy storage system stores electricity when demand is low and releases it when demand is high. The developer, Plus Power, told the board the facility would help steady the power supply during peak times, such as hot Arizona afternoons when air conditioning drives up demand. Storing power for those peak hours can also help hold down costs, the company said.

Plus Power said the system would be rated at 250 megawatts and 2,000 megawatt-hours. According to the company, if the grid went down, the facility could power up to 100,000 homes for at least eight hours, and as long as 12 to 13 hours depending on demand. These figures were provided by the applicant. The facility will connect directly to SRP's nearby Able substation, less than a mile away.

Three Approvals in One

The project required three separate actions, which the board heard together but voted on one at a time:

A change to the county's comprehensive plan, shifting the land's designation from suburban neighborhood to general public facilities and services. The board approved this with no conditions.

A rezoning of the property from general rural and single-residence zoning to industrial (I3) zoning. The board approved this with one condition.

A planned area development (PAD) overlay, a tool that fine-tunes how the industrial zoning applies to this specific site. The board approved this with 18 conditions.

Senior planner Tanya Bedward told the board the main change tied to the new zoning was a request to remove the 25-foot setback — the buffer normally required between an industrial site and neighboring rural or residential land — and allow a zero-foot setback on one side. She said that side borders a parcel slated for similar energy development, so it made sense for the two to operate closely. The site will still include a landscaped buffer, and an 8-foot decorative wall will surround the facility.

Safety and Fire Questions

Supervisors asked about safety and fire response. Brian Schultz, a safety engineer for the project and a retired Phoenix firefighter, told the board that battery storage technology is now heavily tested and regulated, and that today's batteries are safer than in the past. He referenced the 2019 McMicken battery fire at an Arizona Public Service (APS) facility as a turning point that led to stronger standards.

"The batteries that we're putting in today are highly tested and highly regulated," Schultz said. [Brian Schultz, ~2:20:52]

Matthew Look of Plus Power told the board the nearest fire station is a Rural Metro station about 5 miles to the west, with additional stations to the north and south. He said the site itself uses no water, and that while there is no water line directly to the site, water is available in the area for fire service and the company would truck in water for its own operations building.

Town of San Tan Valley Backed the Project

Although the county board cast the votes, the Town of San Tan Valley supported the project. The applicant's attorney, Nick Wood, told the board that the town's interim planning advisory committee and the Town Council both recommended approval unanimously, and a letter of support from the Town of San Tan Valley was entered into the county's record. San Tan Valley Mayor Daren Schnepf sits on the county Planning and Zoning Commission, which recommended approval of the cases 9-0 at its May 21 meeting.

Look said Plus Power would work with the town's planners on landscaping around the facility.

Before the vote, the county received seven letters of support, and three people spoke in favor at the Planning and Zoning Commission hearing. No letters of opposition were received. A representative of the Arizona Technology Council also spoke in support at the board meeting.

What Happens Next

With all three cases approved, Plus Power can move forward with the Copper Basin project. The company said the facility is expected to operate for about 25 years.