I believe he was referencing the Uranium required for Nuclear Reactors that currently is the most efficient/green standard for generating electricity at scale,

I believe he was referencing the Uranium required for Nuclear Reactors that currently is the most efficient/green standard for generating electricity at scale, althought Thorium-based nuclear power could well solve the "rare" issue http://en.wikipedia.org/wiki/Thorium-based_nuclear_power http://en.wikipedia.org/wiki/Thorium-based_nuclear_power