Tucson added to its growing solar-energy credentials Thursday with the dedication of one of the world's most efficient photovoltaic systems at the University of Arizona Science and Technology Park.
The 2-megawatt photovoltaic system, designed and built by California-based Amonix Inc., is the largest of its kind in the nation.
The so-called concentrating photovoltaic system, at the UA tech park's Solar Zone, uses flat lenses to focus sunlight on high-efficiency photovoltaic cells, which convert the light to electricity.
The 12-acre system consists of 36 massive solar panels - each about the size of an IMAX movie screen - towering up to about 50 feet off the ground on dual-axis pedestals that track the sun horizontally and vertically.
The concentrator design allows the use of far fewer PV cells, cutting construction costs, while the tracking system assures maximum light collection.
"This really is cutting-edge technology - there is to my knowledge nothing like it in the country," Amonix CEO Brian Robertson told a crowd of about 100 attendees at Thursday's dedication.
Tucson Electric Power Co. is buying power output from the system under a 20-year power-purchase agreement approved by state regulators. The system will generate enough electricity to power about 500 homes.
The Amonix system is the second solar array installed at the tech park's 222-acre Solar Zone, which is being developed as a working solar demonstration site. In January, Solon Corp., the Tucson-based U.S. arm of Berlin-based Solon SE, dedicated a 1.6-megawatt silicon photovoltaic array built for TEP on the site. Four other installations are currently planned for the site.
While concentrating PV systems have been installed elsewhere, Amonix's array at the Solar Zone is the biggest to use high-efficiency semiconductor cells known as multijunction cells, Robertson said, noting that all its components were made in America.
Multijunction cells, consisting of many layers of semiconductor material, use more of the light spectrum to generate the highest power-conversion efficiencies known. The technology was pioneered by the National Renewable Energy Laboratory and previously used to power satellites.
Amonix, which has been working to commercialize concentrating PV technology since its founding in 1989, has installed smaller systems using multijunction cells in Nevada, where it opened a solar panel plant in North Las Vegas last fall.
The panels used in the Tucson array are "the most efficient, most powerful solar electric generators in the world," Vahan Garboushian, Amonix founder and chairman, said in his dedication remarks.
The concentrator cells have produced energy efficiencies of more than 40 percent in the lab and 27 percent in the field, said Garboushian, who received an undergraduate degree in electrical engineering from the UA in 1966.
By comparison, most production PV panels have an efficiency rating of 20 percent or less, according to the National Renewable Energy Laboratory.
Amonix's systems can produce power for about 14 to 15 cents per kilowatt-hour on an unsubsidized basis, or 11 to 12 cents per kWh with current government subsidies, Garboushian said.
Power from TEP's overall grid costs customers about 10 cents per kWh. The utility's renewable-energy projects are subsidized through surcharges assessed on customers' bills.
While heat degrades the efficiency of other PV cell media - particularly common crystalline silicon - the Amonix semiconductor cells are designed to maintain most of their efficiency in the high heat generated by concentrated sunlight, Garboushian said.
Several local officials, including UA tech park chief Bruce Wright, said Amonix's presence can only help recruit other solar companies.
"We want to develop the R&D (research and development) component, assembly and manufacturing and workforce training on the site," said Wright, UA assistant vice president for research parks.
Garboushian said Amonix already is considering Tucson as a site for future company facilities.
Meanwhile, the company and TEP continue to plan for a 12-MW concentrating PV system at a rock quarry on South Swan Road, to begin construction this fall.
At a glance
Location: University of Arizona Science and Technology Park, on South Rita Road near Interstate 10.
Size: 222 acres.
Operational systems: 2 MW Amonix concentrating, dual-axis tracking photovoltaic system; 1.6 MW Solon single-axis tracking, silicon photovoltaic (PV).
Planned projects: 5 MW solar thermal system with storage (Bell Independent Power Corp.); 5 MW fixed PV (CTC Electric); 2 MW concentrating PV (Emcore Corp.); 5 MW PV (Foresight/Solar Point).
Contact David Wichner at firstname.lastname@example.org or 573-4181.