Resistance to change is always the biggest obstacle.

Oil companies earned a permanent enemy in me when they messed with the electric car the first time around, and I think they continue to do a disservice in making it seem like fossil fuels are cheaper than they really are in terms of total cost.

Obviously the horse can still do things that the gas car can never do, and the gas car will always be able to do things the electric car can't do. But they have really different uses and advantages.

I think China is set up to surpass the US on the even more critical industry of green power.

There are not a ton of people buying cars - cars are expensive. So people usually go for the cheapest car they can get. And if the price of gasoline falls again, it makes the savings that you get with an electric car harder to realize.

I like to take folks back to the turn of the century when people said 'gas cars can never replace horses because you can feed horses at your house, you get along with them, they're nice.'

Solar, for example - which has typically been thought of as so expensive - is cheap when compared with, for example, the cost of cleaning up the Fukushima nuclear disaster and the Gulf.