[hn_throwaway_99]

4th paragraph of TFA:

> Several companies are now building upon existing techniques for accessing geothermal resources by integrating enhanced geothermal systems (EGS) into operations. While conventional geothermal systems produce energy using hot water or steam, pumped from naturally occurring hydrothermal reservoirs trapped in rock formations underground, EGS use innovative drilling technologies, such as those used in fracking operations, to drill horizontally and create hydrothermal reservoirs where they don’t currently exist.

[nandomrumber]

Sounds like marketing hype to me.

Geothermal reservoirs exist at depth.

Drilling horizontally doesn’t magically reduce the depth, nor the problem that drilling in to hot rock is like drilling in to plasticine, at least for temperatures worth working with.

[micro2588]

In traditional fault hosted (not magmatic) geothermal the convection of the water up the fault brings the thermal energy closer to the surface where drilling depths are economical. This convection heats the surrounding rock and over hundred thousand - million of years brings the background temperature around a large volume at depth surrounding these systems considerably above traditional background geothermal gradients. By drilling into a much larger volume of impermeable hot rock surrounding a very small permeable fault hosted section you can considerably enhance the power potential of a traditional fault hosted geothermal system (the E in EGS). That is what Fervo is doing and why their projects are situated right next to traditional geothermal power plants.

The assumption is that if you can increase drilling efficiencies enough then you don't even need a fault hosted or similar system to bring that energy close to the surface, you can just drill down deep enough to get at similar temperatures. That is a big assumption in the economics.

[sunshinesnacks]

EGS has been around for at least 15 years. See AltaRock Energy as an example (I’m sure there are others). They started almost 20 years ago. https://en.wikipedia.org/wiki/AltaRock_Energy

[nusl]

So it basically says nothing useful other than try to generate hype and make them look good.

[thinkcontext]

No. Current geothermal projects need very specific geology to work, its very rare which is why geothermal is such a small blip in the overall energy picture. Enhanced Geothermal Systems (EGS), the technique Fervo is using, can create the conditions to be able to generate electricity. The hope is this will greatly expand the number of projects that can be developed.

Doesn't that sound useful to you?