## November 7, 2011

### ...AND CHEAPER...:

Smaller, cheaper, faster: Does Moore's law apply to solar cells? (Ramez Naam | March 16, 2011, Scientific American)Over the last 30 years, researchers have watched as the price of capturing solar energy has dropped exponentially. There's now frequent talk of a "Moore's law" in solar energy. In computing, Moore's law dictates that the number of components that can be placed on a chip doubles every 18 months. More practically speaking, the amount of computing power you can buy for a dollar has roughly doubled every 18 months, for decades. That's the reason that the phone in your pocket has thousands of times as much memory and ten times as much processing power as a famed Cray 1 supercomputer, while weighing ounces compared to the Cray's 10,000 lb bulk, fitting in your pocket rather than a large room, and costing tens or hundreds of dollars rather than tens of millions.

If similar dynamics worked in solar power technology, then we would eventually have the solar equivalent of an iPhone - incredibly cheap, mass distributed energy technology that was many times more effective than the giant and centralized technologies it was born from.

So is there such a phenomenon? The National Renewable Energy Laboratory of the U.S. Department of Energy has watched solar photovoltaic price trends since 1980. They've seen the price per Watt of solar modules (not counting installation) drop from $22 dollars in 1980 down to under $3 today.

Is this really an exponential curve? And is it continuing to drop at the same rate, or is it leveling off in recent years? To know if a process is exponential, we plot it on a log scale.

And indeed, it follows a nearly straight line on a log scale. Some years the price changes more than others. Averaged over 30 years, the trend is for an annual 7 percent reduction in the dollars per watt of solar photovoltaic cells.

Posted by oj at November 7, 2011 6:31 AM

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