Drilling cost is usually estimated for drilling in sedimentary rock with assumptions about how casing is run ;)
It is possible that drilling 30,000' of granite has conditions that make the estimation model irrelevant. 5 km isn't really deep enough, anyway. My next post will cover the thermo. It is pretty dang hard to get down to anything approaching $50/MWh. Definitely need more than cheap drilling.
It is important that we discuss cost, but I think the urgency of our need for mass generating non-intermitent power should override costs.
As an example Solar energy as it exists now would have been ridiculed in the late 80s as something that would never be cost effective.
It was the massive subsidies/tax rebate schemes in Germany and later on in other EU countries that open the window for manufacturers to produce at scale and make it the cost competitive source of energy that we see now.
I mentioned this in a previous comment on a biomass thread. We would be better off with EU funds allocated to solving the massification of geo-thermal or the massification of small vessel nuclear reactors, than to continue to pour money into converting coal plants into natural gas plants and opening up new biomass furnaces.
Natural gas and biomass are just a means for governments to play with statistics on 'renewable' pie-charts. Until we solve the problem of mass energy storage of intermitent renewables or a far away nuclear fussion we need to start _now_ deploying non-carbon emitting non-intermitent energy generation.
We have to be realistic and accept that we need to find a means of replacing coal and not all regions have the resources for hydro-generation, geo-thermal is the next best bet considering the time and friction it would take to roll out more nuclear for example.
So, a 1km geothermal well? Break even, and you are limited to only a few places in the world.
A 5km geothermal well (needed for broad power availability)? 25x the cost...
So, sure, if you can get a 25x cost reduction in an already cutthroat industry, all power to you (no pun intended).