Which is why its easiest to normalise everything to surface area, mW/m2
Which requires quite complex FEM modelling or 160 IQ intuition to actually do. You don't currently have any real model either, just lots of talk and some intuition.
I just see someone coming back time and time again with outrageous/misleading/bonkers claims who won't even look at the established figures or simple models. If most of the geothermal energy sources were distributed through the crust then it wouldn't have a linear temperature vs depth profile, but almost everywhere does have a close to linear gradient.
It looks linear to the depth we can drill ... which isn't all that deep.
But we're talking about geothermal energy extraction with wells we
can drill, which as I said reach depths where approximations to the models are valid. I provided the links to the FEM modelling paper which does all the fancy stuff and still predicts close to a trivial model (one single storage with one input and output).
With enough assumptions matching measurements with the accepted levels of radiogenic heating isn't a big problem.
It's accepted science that radiogenic heating makes up a large part of the heat flux in the crust, the paper I linked has plenty of references if you want them. This isn't fringe science, it's just a corner of science which escaped your attention before.
Even if half the energy comes from the crust (as example: "Controls of Radiogenic Heat and Moho Geometry on the Thermal Setting of the Marche Region (Central Italy): An Analytical 3D Geothermal Model"
https://www.mdpi.com/1996-1073/14/20/6511) it doesn't change the fundamental limit of the surface flux. If you pull more than the surface flux out of the area, you are reducing the temperature of the thermal storage. Unless you want to argue that we have an imbalance of thermal flux and the earths core is currently increasing in temperature, then all (100%) of the thermal energy produced (from any depth) is released as the surface flux.
Yes you can have a deep well and suck up heaps of power, but thats flux that
doesn't come up where it used to. Hence sticking to mW/m
2 as the measure of available sustainable resource. Which the paper you link to here leads with as Fig 1. Its not surprising they can point to locations with high crustal activity and low flux across the Moho discontinuity, such as the South Australian Heat Flow
Anomaly. But the sustainable power production is still 100mW/m
2 (even in that unusual and "highly active" [for the geological age] region)