[–] rocket-surgeon 0 points 1 point 1 point (+1|-0) ago (edited ago)
Only a very minor fraction of the energy we use is from geothermal sources. Losing the sun would be game over more or less immediatley. Getting radioactive materials from the core is impossible due to gravity causing pressure; we can't dig even more than a small part of the outer crust of the planet.
That being said, the small concentrated area that is the best candidate would probably be Iceland. You could perhaps last a few more minutes if you are close to a volcano.
[–] dozensofish 0 points 5 points 5 points (+5|-0) ago
Good luck with that.