Ray Kurzweil: “One of my primary theses is that information technologies grow exponentially in capability and power and bandwidth and so on. If you buy an iPhone today, it’s twice as good as two years ago for half that cost. That is happening with solar energy — it is doubling every two years. And it didn’t start two years ago, it started 20 years ago. Every two years we have twice as much solar energy in the world.

Today, solar is still more expensive than fossil fuels, and in most situations it still needs subsidies or special circumstances, but the costs are coming down rapidly — we are only a few years away from parity. And then it’s going to keep coming down, and people will be gravitating towards solar, even if they don’t care at all about the environment, because of the economics.

So right now it’s at half a percent of the world’s energy. People tend to dismiss technologies when they are half a percent of the solution. But doubling every two years means it’s only eight more doublings before it meets a hundred percent of the world’s energy needs. So that’s 16 years. We will increase our use of electricity during that period, so add another couple of doublings: In 20 years we’ll be meeting all of our energy needs with solar, based on this trend which has already been under way for 20 years.

People say we’re running out of energy. That’s only true if we stick with these old 19th century technologies. We are awash in energy from the sunlight.”

The Sun – The Big Picture – Boston.com