India and China are exploring throium. There is still a long way to go for developing a viable system. Its one thing getting something to work, its quite another have a standard model that you can economically replicate.
They have the ores, so they might as well. We don't, so we may as well stick with uranium, as its an estalished technology.
However, we are exploring fusion, which you could argue is a much further end game, as at least we know thorium works. But I guess we also know that thorium is unlikely to become a cheap energy source, while fusion has the potential to be.
Meanwhile some numbers for people to consider:
Average world GDP grew by 3.7% in 2011. Lets be nice and say its 3% growth each year.
If we keep this rate of growth, and increase our energy demand accordingly year on year, how long will it be before we equal the total energy that the sun delivers to the Earth?
Well, in 2008 - Total Energy production was 143851TWh (143.85*10^15) or 16.4TW every hour
Total energy hitting the Earth from the sun per year: 1524.24EWh (1524*10^18 ) or 174.0 PW (174*10^15) every hour
Total energy the sun produces every year: 3369096YWh (3369096*10^24), or 384.6 YW (384.6*10^24) every hour
Total output of the milkyway galaxy: 4.38*10^40Wh annually or 5*10^36W every hour
If global energy growth stays at 3% per year, then by the year 2794 our energy demands will exceed what hits the Earth from the sun
By 3985 it will exceed the total output of the sun. We would need a Dyson sphere or the surface of the Earth will be hotter than the surface of the sun. OK, this is a bit silly, but theoretically true.
By 4773 it will exceed the output of the milkyway galaxy!
OK, a bit of fun.
Reasons why this won't happen include:
Population should level out due to urbanisation, development, conflict [delete as appropriate]. Population growth is currently at 1.1%.
We would need to have enough resources to use that much energy
It assumes constant growth, when we don't need to - OECD countries do not grow that much, it is developing countries that is pushing the growth rate, and when they develop up to a certain point, energy demands should level out.
We have to make sure it doesn't.
Add your own reasons on top of these.
Basically, the world needs to work towards a steady state economy. Not easy, and will take generations.
