Largest Commercial Solar Rooftop System in Arizona Unveiled

Empire Power Systems this week completed the installation of an $11.5 million, 2.4 megawatt SunPower solar rooftop system on the Cowley Industrial Park building in South Phoenix. The project is the largest commercial solar rooftop system in Arizona and the second largest in U.S.

Cowley Companies, a Phoenix-based real estate investment firm, decided to install the solar system on this 850,000-square-foot warehouse because it houses food-service tenants that require large refrigerator and freezer units, which translate into high electricity bills. This was the company’s second solar undertaking; last year, Cowley added a 40kW, 188-module fixed mount system to the parking structure at its headquarters on Jackson Street in downtown Phoenix.

“We wanted to provide our tenants with a source of renewable energy that would reduce the property’s electric bills by approximately 40 percent annually,” said Mike Cowley, president of Cowley Companies. “When you consider that last year’s total electric bills for this property exceeded $1 million, you begin to understand how over time this solar system will realize significant cost savings that we can eventually pass on to our tenants.”

Since the system was commissioned Aug. 18, it has produced more than 600,000-kilowatt hours of electric power. It is expected to produce more than 4 million kilowatt hours per year, enough to completely power 340 homes. Additionally, it will offset 3,900 tons of carbon dioxide each year – the equivalent of taking nearly 700 cars off the road.

“This solar system will provide Cowley Companies with a competitive edge in today’s challenging commercial real estate market,” said Brett Burns, Empire Power Systems general manager. “Now the company has a performing asset on its rooftop that is making a positive impact on our environment. The company has a real opportunity to attract new tenants to the space who may not have previously considered it.”

The solar rooftop system features 7,872 ballasted SunPower T-5 panels, the industry’s first non-penetrating rooftop product, which are connected to an above-grade electrical conduit that runs into the inverter room, where four 500kW SatCon inverters convert the direct current energy into usable commercial electricity. Tilted at a five-degree angle, the T5 solar roof tile system approximately doubles the energy generated per square meter compared to systems that are mounted flat to commercial rooftops.

Empire Power Systems, a division of Mesa-based Empire Southwest LLC, served as the solar integrator for this project. Subcontractors (all of which are Arizona-based) include Buehler Brothers Electric, Cannon-Wendt Electrical, Progressive Roofing, Phasor Energy and Fifer Design. The installation was facilitated, in part, by the APS Renewable Energy Incentive Program.