Some Experts Say “Moore’s Law Does Not Apply To Solar PV” – Kurzweil (and Page) Disagree

Exponential growth of computing. 20th to 21st ...Image via Wikipedia

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.

ComputerWorld, in an article two weeks ago, assesses this comparison as flawed. (As did Harry Gray of Cal Tech, as I reported earlier today.)

“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.

However, there are other opinions. The best explainer and interpreter of Moore’s Law, and exponential growth in general, is Ray Kurzweil. His Law of Accelerating Returns is essentially a generalization of Moore’s Law that applies to all information technologies. (Learn a lot more about accelerating returns and exponential growth in his recent book, The Singularity Is Near: When Humans Transcend Biology.)

A panel convened by the National Association of Engineers, including Kurzweil and Larry Page of Google, concluded that:

“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!)

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Is this solar energy analysis is too simplistic?

According to this analysis from Clean Edge, (which I saw originally in the San Jose Mercury News, Solar energy cost may rival other forms soon, study says –

Solar energy will cost the same as power produced by coal, natural gas and nuclear plants in about a decade, a report released Tuesday suggests. By then, the price parity could propel solar adoption so that it accounts for 10 percent of U.S. electricity generation by 2025

If you listen to this kind of thinking, solar energy (which is defined as what, by the way?) is still far more expensive than other kinds. But solar energy, even today, has a finite payback time – if I put solar collectors on my roof, for example, eventually they will pay for themselves.

So that’s one way it’s wrong.

Secondly, the study assumes that conventional energy prices will go up by 3% per year. That could be a slight underestimate. Didn’t we just experience a three month period where gas prices nearly doubled? (That’s 100%, folks!).

I can’t make any argument about the assumption that solar energy prices will come down 18% per year. That’s a lot, by one metric, but we’ve certainly seen large and faster price drops in high tech in the past. Even the iPhone last month, which dropped in price by almost 50% in less than a year. Sure, that was partly through some magic AT&T financial pixie dust, but to the user, it’s a clear 50% price cut. There’s no reason similar magic pixie dust, whether from the government or from the utilities themselves, won’t contribute to market price declines.

The claim that solar currently accounts for less than 1/10th of a percent of the U.S. energy supply today is fine. But the assumption that it will still be less than 1 percent in 2015 (seven years from now) is curious. If we start at .1 percent, and double our solar usage every year, we end up at 128 times as much – 12.8% of today’s total. This is the amazing power of Ray Kurzweil’s “Law of Accelerating Returns.” Even if it takes two years for each doubling, we’re still up a factor of 32x in seven years. That means 3.2% today’s usage. Our total energy usage may also go up (although there are very good reasons to think it may not go up much and and will be starting a downward trajectory), but for a 32x increase in solar supply to translate to 1% of our total energy use, total energy use would have to double. Not too likely in the U.S., where population growth has stopped, and SUVs are starting their long decline.

Finally, there’s good reason to believe that solar energy will actually have a much larger share of U.S. energy usage, due to the power of “negawatts” (as explained brilliantly by Amory Lovins in this series of talks at Stanford in 2007), in which efficiency turns out to be the most cost effective way to power industry and create profits. Oh, and by the way, it significantly reduces our energy usage, by as much as a factor of five to seven!

The article combines a couple of types of fallacious thinking – that technological progress is linear, for example, rather than geometric, and that other factors, such as the desire to reduce greenhouse gases or realizing the benefits of negawatts throughout the economy, don’t have an additional accelerating effect on technology changes.