thanks, I love getting information from folks based on their personal experience.

I sort of (but not fully) knew about the corrosive aspects in that if I recall, notable drawbacks include "hard" (mineralized) water damage to equipment. I think another drawback may be seismic activity caused by the plant? Or just happening around the area?

The stories though covering very deep geothermal are new to me though.

@kmaz I doubt any geothermal well will be "wet" if too deep (need to be "wet" for steam). They are very corrosive mainly after the well is producing. Add water + heat + mainly carbon dioxide/ H2S then expose to air and metal rusts very quick, which is what wells are cased with. After we completed the wells, used to let them rip for a day to blow all sand/ grit out so it didn't sand blast the pipelines to the turbine/ power station. 112 decibels we recorded one at, like standing next to a jet engine going full bore. Silicon also a hazard.
I did drill a dry geothermal well near Innaminka in Australia. A thermal Geo incline comes near the surface there with hot granite. As granite is dry, had to drill 2 wells and join them at the bottom ie water down one, steam comes up the other. Geothermal is usually drilled in metamorphic rock around the edges of the tectonic plates, the "ring of fire" where active volcanoes are found and are earthquake prone areas.

@puff

Thanks for the further info, very useful.

I think for this new approach to trying to go miles deep, they are trying to develop new technology which would address the list of reasons that it is difficult or impossible. I guess time will tell. I've only recently heard of these types of efforts, and haven't formed a strong view.

@kmaz Think we need to adapt to where we are eg constant steady breeze go wind generators, in a geothermal area go geothermal, lots of sun solar, big tides then chuck a turning paddle wheel there. Have generators that work on waves/ swell now. Use vegetive composting gases, build insulated housing and face them the optimum way for heating/ cooling etc. Use our big brains a bit.
Saying this, should never put our eggs in one basket so a combination of ways to generate power is wise so you have a backup plan.
It all comes down to economics. Drilling deep wells has a lot more risk, takes more time and is expensive. Would suggest if geothermal is not obviously present in your area, a bit bizarre to keep drilling until you find it and not cost effective.

@puff

yes in my work i've always advocated for keeping many low carbon (and energy conserving) energy options open. there is no need or smartness in my opinion to advocating for just one as "the answer" to the climate emergency.

in this case the idea of much deeper geothermal is one i didn't know existed or was being researched until the recent stories. so it is to my eye a new additional option that has been added to the toolbox, at least at the research level. we''ll see if they pull it off at all. if they do i predict inadequate attention will be paid to precautionary principle considerations and research in bringing it to market