February 22, 2012


Making Solar Power Competitive with Coal: A study identifies early-stage technologies that could be combined to cut the cost of solar panels in half. (KEVIN BULLIS, 2/22/12, Technology Review)

The report, from researchers at MIT led by Tonio Buonassisi, a professor of mechanical engineering and manufacturing, identifies early-stage technologies that, if employed together, could reduce the cost of making solar panels to 52 cents per watt. Currently, the cost is over a dollar per watt. At 52 cents per watt, assuming similar cost reductions for installation and equipment such as inverters, solar power would cost six cents per kilowatt-hour in sunny areas of the U.S.--less than the average cost of electricity in the U.S. today. Solar power in sunny areas now costs roughly 15 cents per kilowatt-hour, according to the U.S. Department of Energy, although the cost can be sharply higher in small installations or in cloudy areas where solar installations generate less electricity.

The best way to reduce the cost per watt is to make solar cells more efficient--as a result, more power can be produced with a given amount of material and factory equipment. Increasing efficiency also decreases installation costs, since fewer solar panels are needed. But efficiency improvements aren't enough to reach 52 cents a watt. Manufacturers will also need to make solar cells from thinner silicon wafers, make wafers in a way that wastes less silicon, and speed up manufacturing. If a high-efficiency solar cell design slows down manufacturing or requires thick wafers, it likely won't lead to the necessary cost reductions.

One major way to reduce costs involves technologies that offer an alternative to the wasteful process now used to make silicon wafers. Currently, half of the high-quality silicon needed to make wafers ends up as waste. One startup, 1366 Technologies, makes thin wafers directly from a pool of molten silicon. It plans to replace conventional crystallization furnaces, sawing stations, and ingot-handling equipment with a single machine that requires fewer workers to operate. Others startups are replacing sawing with processes that free thin wafers of silicon from a larger piece of silicon using chemical etching, or by peeling them off.  

Posted by at February 22, 2012 5:38 PM

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