A new solar plus storage system planned for Cochise County will help Tucson Electric Power (TEP) provide more clean energy when our customers need it most.

The Winchester Solar facility will include an 80-megawatt (MW) solar array and an 80 MW battery system that will come online in 2027. Torch Clean Energy will build, own and operate the systems for TEP on a site about 18 miles west of Willcox. The facility will produce enough energy each year to serve the annual energy needs of about 11,000 homes.

TEP expects to charge the grid-connected batteries in the morning and early afternoon, when solar resources are most abundant. This allows delivery of stored energy later in the day, when customers’ energy use typically peaks. The 320 megawatt-hour battery system can provide 80 MW of AC energy for four hours when fully charged.

“Energy storage helps us maintain reliability as we transition to cleaner energy resources,” said Susan Gray, TEP’s President and CEO. “This new system will help us make the most of an abundant, affordable energy resource by shifting solar energy to periods of greatest need.”

TEP’s expanding energy storage portfolio also helps to smooth energy imbalances throughout the day as clouds block the sun or energy use changes. The company’s latest integrated resource plan calls for expanding storage capacity from 51 MW currently to 1,361 MW in 2038.

The Winchester Solar facility will complement TEP’s recent and planned additions of clean energy resources that will help the company work toward achieving net zero carbon emissions by 2050. They include:

  • The 250-MW Oso Grande Wind Project, located in southeast New Mexico. Owned and operated by TEP, it can generate enough energy to serve the annual electric needs of about 100,000 homes.
  • The Wilmot Energy Center, which includes a 100-MW solar array and a 30-MW battery energy storage system south of Tucson International Airport. It is owned and operated by NextEra.
  • The 99-MW Borderlands Wind Project, located about 100 miles south of Gallup, New Mexico. Also owned by NextEra, it includes 34 turbines that produce enough power to serve about 26,000 homes every year.
  • The 12.5-MW Raptor Ridge solar system near Interstate 10 and East Valencia Road can produce enough power to meet the annual electric needs of about 2,500 homes. It serves homeowners and renters participating in TEP’s GoSolar Home program.
  • The 200 MW Roadrunner Reserve system, coming online in 2025, will be TEP’s largest energy storage system and among the largest in Arizona. The system, to be developed near a southeast-side TEP substation, can store 800 megawatt hours of energy, enough to serve approximately 42,000 homes for four hours when deploying at full capacity.

The Winchester Solar project was selected through an all-source request for proposals issued in 2022. This process identifies the most cost-effective project among competing proposals that satisfy certain energy requirements, in alignment with our long-term integrated resource plans. The process is overseen by Sargent & Lundy, an independent third party.

TEP and sister company UniSource Energy Services are currently evaluating proposals submitted in response to a joint all source request for proposals issued in December 2023. The request identified a need for up to 625 MW of renewable and energy efficiency resources and up to 825 MW of “firm capacity” resources that could be called upon at any time. These could include energy storage systems and demand response programs that provide incentives to customers who curtail energy use when resources are needed elsewhere.

TEP provides safe, reliable electric service to more than 447,000 customers in Southern Arizona. For more information, visit tep.com. TEP and its parent company, UNS Energy, are subsidiaries of Fortis Inc., a leader in the North American regulated electric and gas utility industry. For further information visit fortisinc.com.

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