Nuclear power

Types

Type	Problems if scaled up
	Fuel scarcity	Weapons proliferation	Nuclear waste
Conventional nuclear power	Problem	Low risk	Problem
Small nuclear reactors	Problem	High risk	Problem
Uranium-238 breeder reactors	Abundant	High risk	Almost none
Thorium-232 breeder reactors	Abundant	Low risk	Almost none
Hydrogen fusion (not viable yet)	Abundant	Low risk	Almost none

So far, it seems that thorium is the only nuclear power that could really scale up enough to replace all fossil fuels.