As you go deeper under the surface of land or oceans the crust gets hotter ocean water adds about .4 PSI per increased foot of depth but rock adds about 1.4 PSI per foot of depth. Somewhere between about 5 to 7 miles deep under most land areas and about 2 to 5 miles deep under most ocean bottoms that are on average about three miles in depth you can start to efficiently extract geothermal energy. Over time and with improving technologies it will be possible from one shaft starting point to diagonally drill down to access tens of thousand years of hot electric generator operating rock for most local needs. Large metro areas will need to reach out a little at a time over the centuries but will mostly for the first hundred years get all of their energy from points within their boundaries.
CO2 and not the classic water to steam generator is proposed because it is not likely to migrate minerals that corrode and foul up equipment and plug passages.
Side flame cutting drill packs are needed to drill 500 to 4000 foot side holes from the expanded diameter production thermal zone shafts. These side holes might only be 1to2 inches in diameter and might be drilled slightly up grade to help remove rock dust and even pressurized super critical water from them.
the flame cutting drill strings might be left in place after drilling is complete to carry CO2 thermal extraction super critical pressurized gas to the end of the holes. Think of these holes as low conductive energy underground boiler tubes or passages in a nuclear reactor.
This is a nonproprietary open source presentation.
mist of these ideas in their basic form are already covered by long used and publicly demonstrated devices and components that have occasionally been patented decades to over a century ago.
All ideas in here are free to be used by anybody. All word combinations above can be copied, exchanged or edited for improvement without any permission and claimed as your own if you choose.
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People as individuals and institutions or industries are encouraged to write their own versions and engineer, build, test and sell their own systems specifications and products.
A final standard will evolve or the human race will cease to progress along these lines and take the deteriorating human economy directions that we can all read about in libraries full of minute details.
Jim Burden 2019