Facts of the Matter
Solar energy technology begins to shine
Solar technology is really hot, and green as well!
Photovoltaic systems are being installed in more and more locations because of the high cost of electricity that is largely generated from carbon-based fossil fuels. The first generation of silicon solar panels is rapidly becoming obsolete.
First-generation photovoltaic cells are built in a clean room using a chemical process that is the same as that used to make silicon wafers for computer chips. Pure silicon ingots are produced at high cost from sand, then sliced and doped with controlled impurities at high temperature.
Second-generation photovoltaic technology uses about 1 percent of the silicon per watt by spraying a silicon vapor on glass or plastic in a vacuum. It is cost-effective only on a large scale because the technology is subject to failure.
Third-generation solar technology is a real breakthrough. It uses space-age chemicals, mostly copper-indium-gallium-selenide (CIGS) on a thin, flexible film of aluminum foil or polymer, and produces solar panels at a fraction of the cost of first- or second-generation solar technologies.
The electrical output of third-generation photovoltaic panels is priced competitively with electricity generated by fossil fuels, which some consider to be solar power's "holy grail." Third-generation CIGS promises to revolutionize the industry.
The catch is that the copper, indium, gallium and selenium must be in precise atomic ratios in order to capture photons and release electrons, and the composition is difficult to control.
Several startups have entered the market using similar technologies albeit with slightly different applications.
Nanosolar began producing thin film panels using inkjet printers to spread nano particles of CIGS for one-fifth the cost of traditional photovoltaic cells, about $1 per kilowatt. Nanosolar has demonstrated a cell efficiency of 14.5 percent, comparable to the 18.8 percent efficiency achieved by the best vapor-deposited CIGS on glass cells, and superior to the 9.8 percent achieved by amorphous silicon cells.
Nanosolar's entire order books are filled until mid-2009. Much of it will cover a field in Germany, where they will open a second production plant, with enough thin film photovoltaic panels to produce 10 megawatts. The time frame for this is one year compared with a decade to build a 10-megawatt fossil fuel or nuclear plant.
Another company, PowerFilm, sells panels 20 microns thick that produce nearly 4 watts per square foot. A small 1,000-square-foot roof could produce 4 kilowatts and would weigh only 120 pounds.
The army is testing prototype tents made by PowerFilm that produce one kilowatt to charge batteries and run low-power electronic equipment.
Commercial applications of these technologies that will allow individuals to produce their own solar energy at reasonable cost is probably 10 years away.
Hewlett-Packard has partnered with PowerFilm to expand its inkjet technology and is already making 500 million of them annually.
Imagine roofing your house with solar panels printed on site to a specified size. In Hawaii, where we have 300 or more days of sunshine per year, this could be a huge step toward energy independence.
, professor of science at Honolulu Community College, teaches earth and physical science and investigates life and the universe. E-mail questions and comments to firstname.lastname@example.org