Efficient, Cheap Solar Cells

A cheap new way to attach mirrors to silicon yields very efficient solar cells that don't cost much to manufacture. The technique could lead to solar panels that produce electricity for the average price of electricity in the United States.

Suniva, a startup based in Atlanta, has made solar cells that convert about 20 percent of the energy in the sunlight that falls on them into electricity. That's up from 17 percent for its previous solar cells and close to the efficiency of the best solar cells on the market. But unlike other high-efficiency silicon solar cells, says Ajeet Rohatgi, the company's founder and chief technology officer, Suniva's are made using low-cost methods. One such method is screen printing, a relatively cheap process much like the silk-screen process used to print T-shirts.

So far, the high cost of solar cells has limited them to a marginal role in power production, accounting for less than 1 percent of electricity worldwide. Rohatgi calculates that the company's low-cost manufacturing techniques will make solar power competitive with conventional sources, producing electricity for about 8 to 10 cents per kilowatt-hour--the average cost of electricity in the United States and far less than prices in many markets.

To be sure, significant work remains before the goal of 8 to 10 cents per kilowatt can be achieved. Suniva has demonstrated the crucial first step, which is to show that it can make solar cells that are more than 20 percent efficient using screen printing. The results have been confirmed by the National Renewable Energy Laboratory, in Golden, CO. But for those tests, Suniva used cells with 200-micrometer-thick silicon wafers, and reaching 8 cents a kilowatt will require 100-micrometer wafers. That this is technically possible has been established.

via Technology Review via FuturePundit