An Arizona electric and natural gas utility will soon issue a request for proposals to develop new renewable energy, energy storage, and energy efficiency projects.

UniSource Energy Services said it aims to issue an All-Source Request for Proposals on April 19 with a deadline of July 1.

The request for bids will seek up to 170 MW of renewable and energy efficiency resources, which could include solar and wind generating systems as well as new energy efficiency initiatives and demand response programs.

The utility said it is also looking for up to 150 MW of energy storage systems capable of dispatching at least four hours of energy every day during the summer. This category could also include demand response initiatives for customers to cut demand during peak load times, UniSource said.

UniSource set new peak energy demand records in both 2020 and 2021, highlighting the need for additional generating capacity, energy efficiency programs, and demand response initiatives to meet customer needs.

UniSource Energy Services' 5 MW Steven H. Jacobson Solar Facility (Courtesy: UniSource)

Proposed projects are expected to enter service as soon as May 1, 2024, but no later than May 1, 2025. UniSource said it would announce the winning proposals late this year.

The utility's integrated resource plan calls for 50% of the energy provided to retail customers to come from renewable sources by 2035. In 2019, clean energy resources provided around 22% of retail electricity sales.

UniSource currently has about 142 MW of solar and wind resources in its community-scale portfolio.

The IRP also calls for UniSource to reduce its reliance on wholesale markets by increasing its use of owned or contracted generating resources.

UniSource provides natural gas to 165,000 customers in northern and southern Arizona, as well as electric service to more than 100,000 customers in Mohave and Santa Cruz counties. The utility and its parent company, UNS Energy, are units of Fortis Inc.