QuoteThe key is that the resulting solar cell has efficiencies--or the amount of sunlight the solar cell can turn into electricity--that are closer to crystalline silicon solar cells than thin-film alternatives such as amorphous silicon or copper indium gallium selenide or CIGS. Crystalline solar cells have higher efficiencies than thin films. Commercial crystalline panels can convert up to 22 percent of sunlight into electricity, without concentrators. CIGS makers are initially shooting for the mid to low teens. The catch is that making crystalline solar cells is expensive. The patterning and other processes is similar to what is used in making LCD panels. Innovalight says it could conceivably cut the production price by around 50 percent or more. Many start-ups, however, had hit bumps in bringing new (albeit different) manufacturing techniques for solar cells to market.
QuoteSince solar energy can't be harvested all the time, the panel is actually far larger than would be necessary to simply power the router. In Florida, which gets about 4.5 hours of peak solar energy a day, Solis installs a 220-watt solar panel that measures about 4 feet by 5 feet. Ordinarily, a router only needs about 24 watts of power, he said. All that extra power goes to recharging the batteries, which run all night. The batteries in the system let the routers survive cloudy periods and can actually keep the router going for seven days without a recharge, Reynolds said.
QuoteUsing a novel technology that adds multiple innovations to a very high-performance crystalline silicon solar cell platform, a consortium led by the University of Delaware (UD) has achieved a record-breaking combined solar cell efficiency of 42.8 percent. The current record of 40.7 percent was attained in December 2006 by Boeing's Spectrolab, Inc. Honsberg said the previous best of 40.7 percent efficiency was achieved with a high concentration device that requires sophisticated tracking optics and features a concentrating lens the size of a table and more than 30 centimeters, or about 1 foot, thick. The UD consortium's devices are potentially far thinner at less than 1 centimeter.
QuoteInstallation is one of the major problems with solar energy. The electricity generated by solar panels is free, but solar systems are not: typically it takes about eight years of free electricity before a consumer breaks even. The solar industry wants to reduce the break-even point to about four years. The industry spends millions in R&D every year to come up with solar cells that can convert more of the sun's energy into electricity or reduce the cost of producing solar cells. These systems, however, mostly get installed the old-fashioned way: contractors hoist panels onto the roof and drill and screw them into place. About half of the cost of a solar system goes to the inverter (a device that converts the direct current from the solar panel into alternating current) and to installation, said John Langdon, vice president of marketing at HelioVolt.
QuoteOverall, these changes result in a 43 percent increase in power, said Julie Blunden, vice president of external affairs at SunPower. Each panel can generate 315 watts of electricity and will have roughly the same cost per watt as the existing line, she said. The theoretical limit of monocrystalline silicon cell efficiency is about 25 percent, Blunden said.