Tucson Electric Power is preparing to build new grid-tied solar arrays on the roofs of large public buildings to help serve a growing demand for renewable power.

Through its new TEP Bright Roofs program, the company plans to lease space atop schools and other public facilities for the development of 11 MW of new TEP-owned solar generating capacity over the next three years. TEP Bright Roofs will feed solar energy directly into TEP’s local distribution grid, generating enough clean power to serve more than 1,800 Tucson homes.

“Our new TEP Bright Roofs program offers schools and other public agencies an opportunity to put their unused rooftop space to good use, generating both clean energy for our community and lease payments that can help support education and other public services,” said Paul Bonavia, Chairman, president and CEO of TEP and its parent company, UniSource Energy.

The program is designed for buildings with at least 50,000 square feet of flat rooftop space, enough room for a photovoltaic system that generates about 250 kW. A high school with 200,000 square feet of available roof space could host a 1 MW system that generates enough power to serve about 170 homes.

TEP Bright Roofs will incorporate low-profile, high-efficiency T5 Solar Roof Tile systems from SunPower Corp. of San Jose, California. The system can be installed without roof penetrations, making it relatively easy to remove for roof maintenance or recoating. Tilted at a five-degree angle, the T5 Roof Tile system approximately doubles the energy generated per square meter compared to systems that are mounted flat onto commercial rooftops.

TEP Bright Roofs will be part of more than 125 MW of new solar generating capacity that TEP and its partners are developing in the Tucson area over the next three years. The output of those systems will help TEP satisfy Arizona’s Renewable Energy Standard, which calls on utilities to increase their use of renewable energy each year until it represents 15 percent of their power in 2025.

The total installed cost of TEP Bright Roofs will be comparable to TEP’s other utility-scale systems. The energy generated by TEP Bright Roofs will be available to TEP customers through the company’s Bright Tucson Community Solar Program. Participating customers can purchase 150 kWh “blocks” of solar energy, offsetting an equivalent amount of conventional power at a price that adds $3 apiece to their monthly bills. TEP customers can purchase some or all of their energy through the program, reducing or eliminating their use of fossil-fueled energy.

TEP customers have subscribed to more than 1,100 blocks of solar energy since the Bright Tucson Community Solar Program was launched Feb. 1. Solar power for the program currently is generated by a 1.6 MW solar array in the Solar Zone at the University of Arizona’s Science and Technology Park in southeast Tucson.