Breakthrough Solar Concentrator:low cost with high efficiency

Morgan Solar has the Light-Guide Solar Optic (LSO), a thin optical structure made of acrylic and/or glass that internally concentrates sunlight. They are targeting less than $1 per watt by 2011 and close to 30 percent efficiency at costs competitive with thin film. So two to three times cheaper and 50% more efficient that most competition.

* revolutionary new way to capture, transport and concentrate sunlight
* Up to 1400 suns of concentration, with a clear path to many thousand suns in the future
* Ultra thin optical structures that capture, transport and concentrate sunlight
* Light is redirected onto tiny slivers of PV at the edge of the optic – not underneath
* Eliminates the bulkiness of traditional CPV systems
* Not affected by thermal expansion
* Extremely low cost
* Light-weight and rugged
* Easy to manufacture

Morgan Solar’s high-precision optic–part acrylic and part glass–is molded so that light is trapped and bounces toward its center. A secondary glass optic concentrates the light to 1,000 suns and directs it to a tiny, high-efficiency solar cell. The low-profile design promises to reduce the cost of manufacturing and transportation.

Most concentrators tend to be complex systems that use special lenses, curved mirrors, and other optical components with a “nonzero” focal length. This means that there must be enough distance–an air gap–between the solar cell and the optic to properly focus the light. As a result, concentrator-based systems are usually packaged within bulky enclosures, with enough depth to accommodate the focal length and protect all components during shipping. This means higher material and assembly costs and more expensive shipping.

A couple of years ago, Nicolas’s brother John Paul Morgan came up with the idea of a solid-state solar concentrator system: a flat, thin acrylic optic that traps light and guides it toward its center. Embedded in the center of Morgan Solar’s concentrator is a secondary, round optic made of glass. With a flat bottom and convex, mirrored top, the optic receives the incoming barrage of light at a concentration of about 50 suns and amplifies it to nearly 1,000 suns before bending the light through a 90-degree angle.

Morgan Solar’s technology still requires a tracking system to keep it facing the sun. Researchers at MIT have eliminated the need for trackers by developing special dye coatings that can absorb diffuse light, but Morgan Solar’s technology is closer to market. Nicolas Morgan adds that trackers today are precise, reliable, and add “marginal” cost for 44 percent more power. Some business and engineering decisions must still be made, but he expects that the company will be able to build its system for less than $1 per watt by 2011–“and with some vertical integration, considerably less.” This would lead to a product close to 30 percent efficient at costs competitive with thin film.

“I think the concept should be pursued,” says engineering professor Roland Winston, an expert in nonimaging optics at the University of California, Merced. He does, however, question the use of acrylic as a concentrator material: “Acrylic has not been proven for long-term use, especially under concentrated sunlight.”

John Paul Morgan says that’s the main reason why the company is using both acrylic and glass in its system. The company has intentionally limited concentrations within the acrylic portion to 50 suns and has the smaller glass optic doing the heavy lifting. “We want this system to last for 25 years, so we’re trying to really understress the material,” he says. “Once we’ve proven we can push the acrylic further, we’re going to shrink the glass optic.”

A number of pilot projects planned for 2009 will test the concentrator in the field. The company expects commercial production to begin sometime in 2010.