Although we all should cheer the fact that energy derived from solar power increased dramatically in 2011, champions of alternative energy aren’t quick to boast about the total power it supplied. That’s because it didn’t supply very much.
Solar power capacity (not delivery) increased from 18 gigawatts to 24 gigawatts between 2010 and 2011. The world’s energy consumption was 15 terawatts.
So one burning question about solar is will growth be arithmetic or logarythmic. If the pace is 1, 2, 3, 4, we’ll need to get our coal-digging shovels out. If on the other hand it’s 1, 2, 4, 8 then the magic of compound growth will have solar providing significant energy.
Since all the figures for solar are always given in watts capacity, let’s stay with that measurement instead of my preferred quad.
If energy consumption does double by 2075, we’ll need about 30 terawatts. A bit more than 1,000 times growth. (Oh, don’t gulp yet… it’s undignified. Whimper, moan and beg for mercy…)
If the past–since 1978–is any indication, we’ll actually get there. Solar has increased in capacity by an average of 36% annually–and we only need an increase of 11.6% every year to get there.
Here’s historical performance, courtesy of Professor Emanuel Sachs at MIT:
Now, nobody should think that innovation and penetration can improve at an incredibly high rate forever. Moore’s Law doesn’t cover every industry, and the logistical chain for microprocessors is infinitely more complex (and therefore amenable to continuous improvement) than the chain for solar power.
But it doesn’t have to improve forever–if it improves for four more years it’ll be cheaper than electricity provided by coal in most places and it’ll be off to the races. Increased installations of solar will cease to be driven by improvements and begin to be driven by comparative advantage.
We won’t mind.