I would just guess off the top of my head that, because of the sheer volume of the earths interior and the amount of energy stored there as heat, the energy to

I would just guess off the top of my head that, because of the sheer volume of the earths interior and the amount of energy stored there as heat, the energy to run our entire civilisation for 1000's of years would be trival compared to it. http://hyperphysics.phy-astr.gsu.edu/hbase/Geophys/imggeo/earthsect2.gif http://hyperphysics.phy-astr.gsu.edu/hbase/Geophys/imggeo/ea... The 4.7 km well is still in the earths crust, not even reached the lithosphere. As far as the earths interior is concerned it might just be like an era of slightly increased vulcanism.