Volts Podcast - Very interesting geothermal discussion

This is a great episode about geothermal, very technical and practical. I'm curious about the fracking side of it - this has been controversial in traditional oil fracking, not only because of the fossil fuel side of it but also the effect it has on nature.

What do you think? Is it a necessary evil if (as they say) it would provide enough energy to last until the heat death of the universe?