Exhibit 23

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in Registration Statement No. 333-231982 on Form S-3 of our report dated February 11, 2021, relating to the financial statements of Tucson Electric Power Company and subsidiaries, appearing in this Annual Report on Form 10-K for the year ended December 31, 2020.

/s/ Deloitte & Touche LLP

Phoenix, Arizona

February 11, 2021