GreenField’s solar concentrators are engineered to track the sun from dawn to dusk, gathering every available ray of sunlight and generating power long before — and long after — traditional solar panels would generate any significant power.
Most of the concentrator’s large parts are either off-the-shelf or have been designed for inexpensive fabrication.
But its most important components — the computerized electro-mechanical sun tracking system and its solar cells — have been designed from the ground up. The company has seven patents pending on the system engineering and four pending on the solar cells.
The man who perfected the solar cell that makes the GreenField concentrator possible got the idea 34 years ago.
Bernard Sater, a retired NASA Glenn engineer, GreenField’s chief science officer, came up with the design as a graduate student at Cleveland State University.
Sater, Neil Sater’s father, retired early from NASA and incorporated his own research engineering company in 1994, PhotoVolt, to work full-time developing this one-of-a kind solar cell — and an inexpensive process to manufacture it.
Bernard Sater turned to his old employer for assistance under the Space Act, which allows NASA to assist private companies under a contract
Forget about big panels on your roof. Think chips.
Each chip contains 40 layers of solar cell — engineered to sit on their edges, allowing light to penetrate the silicon wafer edge and electrical power to be easily routed through low-resistance junctions out of the cell’s other end.
One chip is dwarfed by a penny, and to the naked eye the layers appear to be a series of closely drawn straight lines. Because it is so concentrated, the PhotoVolt cell generates high voltages.
The cell structure is like a stack of pancakes, cut in half and then turned on edge, said Sarah Kurtz, a chemical physicist at the U.S. Department of Energy’s National Renewable Energy Laboratory in Colorado and an expert on solar technology.
Each GreenField solar concentrator contains 200 such chips laid out in two strips, each measuring roughly 10 inches by 1¾-inch — generating a whopping 1,500 watts of power.
The cells are about 20 percent efficient at generating electricity, compared with 12 percent to 14 percent for conventional flat solar panels.
Sater thinks the concentrators can be mass produced, delivered and installed for about $6,000 a copy. The company has already sold 15, hand-built concentrators at $10,000 each.
A $6,000 price tag boils down to $4 per watt.
Two Ohio utilities — Duke Energy of Ohio in Cincinnati and American Electric Power in Columbus — have already ordered GreenField concentrators for testing.
The city of Mentor has purchased 10 Greenfield concentrators to showcase the technology and to provide power to the city’s senior center. Construction is under way. The city won grants from the Cleveland Foundation and the Ohio Department of Development to pay for the project.
– from blog.cleveland.com