Arizona-based UniSource Energy Services (UES) said recently it will add to its renewable energy portfolio in 2016 with a large-scale photovoltaic (PV) system in Mohave County and smaller solar arrays for two area schools.

Partially supported by usage-based fees included on customers’ electric bills, known as the Renewable Energy Standard Tariff (REST), the projects were approved by the Phoenix-based Arizona Commission Corporation, which also determined a slightly lower ceiling price for next year.

The structures are included in UES' overall strategy to comply with Arizona's Renewable Energy Standard. This regulation asks utilities to gradually increase their annual use of renewable power until it reaches 15 percent of their total output by the year 2025.

UES intends to spend as much as $10 million next year on a large 5-MW array in Mohave County to supplement its existing facilities near Rio Rico and Kingman. Additionally, UniSource will allocate $60,000 from REST funds to install solar PV systems at Nogales High School and Pierson Vocational High School, also in Nogales, with each array handling approximately 10 kW and saving on the schools’ electric bills. The company has previously installed similar systems ranging from 5 to 12 kW for other Arizona high schools.