Are we wildly underestimating solar and wind power?

Posted by Brad Plumer on June 19, 2012

Right now, renewable energy sources like solar and wind still provide just a small fraction of the world’s electricity. But they’re growing fast. Very fast. Three new pieces of evidence suggest that many policymakers may be drastically underestimating just how quickly wind and solar are expanding.

1) Solar is growing exponentially. Let’s start with this chart from Gregor MacDonald, using data from BP’s 2012 Statistical Review of World Energy, showing that global use of solar power has grown exponentially in the past few years. Watch that graph go parabolic:

Across the globe, 55 terawatt-hours of solar power had been installed by the end of 2011. That may not seem like much in itself — the United States by itself, after all, needed about one hundred times that much power in 2011. But solar has been growing at a stunning rate, as panels keep getting dramatically cheaper. If these exponential growth rates, MacDonald notes, solar could provide nearly 10 percent of the world’s electricity by 2018.

2) Official agencies keep underestimating the growth rate of renewables. Perhaps MacDonald’s predictions sound like a wild fantasy. After all, the International Energy Agency is forecasting that solar will catch on much more slowly — providing a mere 4.5 percent of the world’s electricity by 2035. But here’s the hitch: The IEA has almost alwaysunderestimated how quickly wind and solar can grow.