In May, Denver-based ProLogis, a provider of distribution facilities, launched a rooftop photovoltaic (PV) test site on the roof of its headquarters to test solar panel technologies. The test site, which was created by the company's ProLogis Renewable Energy group, is intended to help ProLogis understand evolving PV technologies and installation difference as it continues to incorporate solar facilities at its buildings.

The test site provides 11 kilowatts in DC power at peak capacity from 99 PV modules provided by eight manufacturers. The configuration provides side-by-side comparisons of various PV module technologies, including monocrystalline, glass-on-glass thin film and membrane-applied thin film modules. The installation also contains 16 individually monitored strings; each tests to a certain parameter.

"As PV technologies evolve and new companies enter the market, it is critical that ProLogis understands the technology and installation differences to ensure we arrive at the optimal solutions for our installations at each building and location," says Walt Rakowich, chief executive officer of ProLogis.

The test site uses eight module manufacturers, including Ascent Solar Technologies, Thornton, Colo.; First Solar, Tempe, Arizona; GS-Solar, Quanzhou City, China; MiaSolé, Santa Clara, Calif.; Solyndra Inc., Fremont, Calif.; Suniva Inc., Norcross, Ga.; United Solar Ovonic, Rochester Hills, Mich.; and Xunlight Corp., Toledo, Ohio.