drilling the well is about $1 million per km. only a few spots around the world make 1-2 km wells cost effective for extracting energy for electricity. this is even worse with the costs of PV installed now 100 fold less than the marginal cost of geothermal.

having said that, a resilient system would have a baseload of electricity from geothermal, some peaking from hydro and plenty of PV/wind. mind you, i'm biased since i live in NZ and we're well on the way to 95+% electricity renewables...

Two things:

1. Capital expenses are quite high, even though running expenses are low.

2. It's only viable in specific geographic places, where heat is brought up close to the surface by magma and water flows. Otherwise you just need to drill too deep to get useful heat. So the big sites are at places like The Geysers in California, the hot springs of Iceland, and the places the site mentions in Kenya.