An energy miracle is coming, and it’s going to change the world.

Bill Gates met with Nate Lewis, a Caltech professor who hopes to turn sunlight into fuel to power our cars, trains, and airplanes.

He visited his lab to learn more about his progress.

What’s simple is the idea behind all of his team’s research: The sun is the most reliable, plentiful source of renewable energy we have. In fact, more energy from the sun hits the Earth in one hour than humans use in an entire year. If we can find cheap and efficient ways to tap just a fraction of its power, we will go a long way toward finding a clean, affordable, and reliable energy source for the future.