The word entrepreneur is associated with success and adventure. From my life, the only thing I can tell you that's consistently associated with entrepreneurship is failure, and the only thing consistently associated with invention is frustration. There is a long road between the idea and the reality.

My biggest worry is I'm running out of time and energy. Thirty years ago I thought 10 years was a really long time.

The city needs a car like a fish needs a bicycle.

Clearly, there are many places where diesel is king or gas-turbine is king, or IC engines will win, but there are many places in the world where, as we've seen, they just won't do the job. The modern version of the Stirling engine has some very, very attractive characteristics, and we're trying to optimize it for some of those applications.

Education, actual learning - it is hard work. It's very personal. Your parents don't teach you anything. Your teachers don't teach you anything. The government doesn't teach you anything. You read it. You don't understand it; you read it again. You break a pencil and read it again.

To me, innovations are the wheel, fire, language, movable type. There are not 3 million innovations; there are 3 million inventions

It’s not what you do – it’s what you are becoming.