Comment by LikeBeans
9 hours ago
I admit I don't know enough, but does it negatively affect the underground water a negative way? I read a while back that geothermal plants (can) use fracking like technique to heat up the water but it has negative effects on the local geology and underground water. But not sure if that's true hencey question here.
Huh, my first reaction was to say that Enhanced Geothermal is actually just a polite way of saying fracked geothermal but it turns out that's not quite accurate. Hydro-shearing (which EGS uses) doesn't intentionally create new cracks in the rock, which fracking does, but will cause existing cracks to grow. Potentially still negative local effects for sure but not as violently, hopefully.
Every project has risks, of course. EGS projects are basically two wells making a circulation loop: inject cold water down one well under pressure, circulate it through hot rocks using the fracked channels, and pull out hot water up the other well.
Theoretically, a leak into groundwater aquifers would make keeping the system pressurized harder or would dillute the amount of heat they're extracting, so seems like a stronger commercial incentive not to f up the groundwater.
In oil fracking they're just trying to pull the oily goo up from underground. And in theory you could do heat extraction using just water instead of shale goo solvents so any contamination would be less impactful?
I dunno, I'm just internet armchair quarterbacking this until a real geologist chimes in, but I can see how this is a somewhat different beast that shale fracking wells.