In his call to action two weeks ago, Al Gore compared the future development of solar electricity sources to the development of the semiconductor industry. His implication was that Moore's Law, which reliably predicted that the price/performance of semiconductors doubled every 18 months, would also apply to photovoltaics.
"But does Moore's Law also apply to the solar energy industry? The short answer is no. As with microprocessor technology, the price and performance of photovoltaic solar electric cell is improving. And Gore can clearly point to price drops of solar cells to make his case. But the efficiency of those solar cells — their ability to convert sunlight into electric energy — is not increasing as rapidly."
The article goes on to suggest reasons that Moore's Law might not apply - there's a lot more to solar panels than just silicon, while the price/kilowatt has been coming down, it doesn't seem to be coming down fast, etc.
"We are not that far away from a tipping point where energy from solar will be [economically] competitive with fossil fuels."
Kurzweil characterizes solar energy technologies as "information technologies," especially as nanotech gets into the picture.
"We also see an exponential progression in the use of solar energy," he said. "It is doubling now every two years. Doubling every two years means multiplying by 1,000 in 20 years. At that rate we'll meet 100 percent of our energy needs in 20 years."
I think we may be at one of the most interesting points in human history, when technology is changing so fast around us that in twenty years the world will almost literally be unrecognizable compared to today. (One of the side effects of the Law of Accelerating Returns is that the world changes completely on a regular basis - it just gets faster and faster!)