how much thorium would power the world

How much thorium would it take to power the whole world?
“Thorium, if efficiently utilized in a reactor, is an energy source of such magnitude that it is not difficult to conceive of an entire planet powered by thorium. It is worth considering for a moment that the thorium required to fuel the entire world's electrical needs would fit in a reasonably sized room, and the thorium required would only be about 2% of the mass of uranium mined today.

In a fission reaction, thorium-232 (having been transmuted to uranium-233) will release roughly 190 MeV of energy per fission reaction. Assuming that the original thorium had a mass of 232 atomic units (u), then that is equivalent to 190 MeV/232 u = 820 keV/u.

How much energy is that? If converted to electricity at 50% efficiency (which can be achieved through the use of a helium gas turbine power conversion system), 820 keV/u is equivalent to 11 billion kilowatt-hours per metric ton of thorium. (Note that a billion kilowatt-hours [BKWH] is equivalent to a terawatt-hour [TWH].)

In 2003, it was estimated that the world produced 16.5 trllion kilowatt-hours of electricity. If this had all been produced by liquid-fluoride thorium reactors, this would have required 1500 metric tonnes of thorium. Future energy projections foresee electrical production reaching 21.4 trillion kilowatt-hours by 2015. To bring the entire world's population up to the level of the average American's electrical consumption would require 80 trillion kilowatt-hours.

Is 1500 metric tonnes a lot? Thorium is a very dense material, and 1500 metric tonnes of thorium metal would only occupy 130 cubic meters of volume, or about the volume of a room 23 ft on a side and 9 feet high."
To put the above numbers in perspective a 2000 lb ton (a short ton) of the highest grade coal contains about 20,000,000 btu of energy; a kilowatt is equal to 3,410 btu/hr. This means that if coal could be converted to heat energy at 100% efficiency (the ‘real’ conversion efficiency in the production of electricity is at best about 39%) then it would take 2,000,000 short tons of coal to produce as much thermal energy as 1 metric ton of thorium! Keep in mind also that the thorium fueled reactor would produce NO greenhouse gases at all while the coal fired power stations produce nearly 8,000,000 short tons of carbon dioxide to produce the equivalent heat. Clearly the world needs to take a hard look at producing energy from thorium.