As always, XKCD seems to have a timely word to say.
Of course, there are other fuels and technologies as well. The energy density for Thorium-232, for instance, is even higher at around 8.2×107 MJ/kg. Deuterium-Tritium fusion is projected to have a density of around 3.3×108 MJ/kg.
To give you an idea of what that all means, the power consumption of the world (as of 2008, if wikipedia can be trusted) was just under 144,000 TW⋅h or 5.18×1020 Joules. The mass of Th232 required to provide the whole world’s energy consumption for a year would then be 5.18×1020J ÷ 8.2×1013J/kg ≅ 6,317,000 kg. That’s 6,300 metric tonnes to produce all the energy the world needs for a year with essentially no carbon footprint. This presumes total efficiency, which is unrealistic of course, but we’re talking about ideal values like what our friends at XKCD are using for the moment.
By comparison, a decent sized coal fired power plant will go through around 30-40 thousand tonnes of coal every day, just to fire one plant to serve one local area, with an immense carbon output.
Nuclear power has certainly got its drawbacks, and we’re examining some of them in our podcasts… but it’s very, very tough to deny the lure of carbon free power generation on this scale. The trick is to make sure the way that power is being generated doesn’t have the potential to be worse than the harm atmospheric carbon does.
