That's the part where the governments have a unique role, and then when it progresses well enough, then existing companies or new startup companies should take it. In the $3 trillion a year energy market, the rewards will be quite fantastic.

There was a concept a long time ago that you would do a different type of reactor called a "fast reactor," that would make a bunch of another element called plutonium, and then you would pull that out, and then you would burn that. That's called "breeding" in a fast reactor. That is bad because plutonium is nuclear weapons material. It's messy. The processing you have to get through is not only environmentally difficultly, it's extremely expensive.

At Microsoft there are lots of brilliant ideas but the image is that they all come from the top - I'm afraid that's not quite right.

If I hadn't given my money away, I'd have had more than anyone else on the planet.

The nuclear approach I'm involved in is called a traveling-wave reactor, which uses waste uranium for fuel. There's a lot of things that have to go right for that dream to come true - many decades of building demo plants, proving the economics are right. But if it does, you could have cheaper energy with no CO2 emissions.

Whenever there is hard work to be done, I assign it to the laziest man as he is sure to find an easy way of doing it. Be lazy, think crazy.

Giving money effectively is almost as hard as earning it in the first place.