The exponential growth of solar power will change the world

It is 70 years since AT&T’s Bell Labs unveiled a new technology for turning sunlight into power. The phone company hoped it could replace the batteries that run equipment in out-of-the-way places. It also realised that powering devices with light alone showed how science could make the future seem wonderful; hence a press event at which sunshine kept a toy Ferris wheel spinning round and round.

Today solar power is long past the toy phase. Panels now occupy an area around half that of Wales, and this year they will provide the world with about 6% of its electricity—which is almost three times as much electrical energy as America consumed back in 1954. Yet this historic growth is only the second-most-remarkable thing about the rise of solar power. The most remarkable is that it is nowhere near over.