Running Some Numbers On Rooftop Solar Energy in 2018

Solar power systems installed in the areas def...
Solar power systems covering the areas defined by the dark disks could provide more than the world total primary energy demand in 2006 (assuming a conversion efficiency of 8%). Image from Wikipedia.

I recently asked physicist Richard Muller whether he thought the price-performance of solar electricity generation would follow a Moore’s Law-type curve. He said that this would not occur due to improving the efficiency of solar collection, as the current levels of efficiency – 20-40% – are reasonably high. However, he added

“I do expect the price to drop by a factor of 10, so we will have lots of solar.”

Well, in the nature of things, there’s definitely a limit to how much energy a solar PV collector can get from a square meter of sunlight. (There’s about 1kw of energy in a square meter – as I learned in Physics For Future Presidents, by Professor Muller – so we can expect to get 400 watts or less.) The amount of this energy per square meter we can collect will go up, but asymptotically approach (at best) the physical limits.

On the other hand, I’d argue that the cost of collecting it can go down a nearly unlimited amount – certainly multiple orders of magnitude. So what will solar PV look like in 2018 – ten years from now?

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