Rising Skepticism

Instapundit linked to this story about the rise of solar power. Here is a problematic excerpt:

"We also see an exponential progression in the use of solar energy," he [Ray Kurzweil] 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."

Except that an exponential rate of expansion is not generally sustainable forever. "If trends continue" is one of those phrases that should light warning signs and sound sirens. Especially when these trends must continue for over a generation. The growth curve for new technologies is generally exponential growth up to point followed by a decline in growth until they hit the market saturation threshold. I expect this to happen with solar power just like it has happened with everything else.

Why? Well among other things, roughly half the planet is dark at any given time. Even more is getting weak sunlight in the morning or evenings. Electrical power transmission is lossy and power storage technologies on an industrial level also stink. So you can't move the power around well or store it well. While I could be wrong, I don't see either of those things changing in the next 20 years because they haven't changed in over a hundred. When it is dark you need another power generation option. You also can't do electrical load balancing with solar. The sun is shining or it isn't. You need generators somewhere that you can throttle up or down to meet supply needs in real time.

The other problem is that outside of cities and suburbs, increasing solar electrical generation capacity will have to compete with arable farm land. Solar makes for a great bottom feeder generation technology in urban and suburban areas. It costs (or will cost) very little to throw it on the roof of your house or factory. Why not do it? But out in the country, most of the land is actually used for growing food. Which is important. Nature and agriculture are also solar powered.

I'm not saying that we aren't on the cusp of a solar power revolution. I actually think we are. New manufacturing processes are set to both drop costs and raise efficiency, but there is an upper limit to what we can achieve. A canna' change the laws of physics. I haven't seen any sort of analysis that realistically addresses that generation threshold. Kurzweil essentially just waves his hand and assumes the problem away, which is just sloppy thinking.