Shale gas is an extension of classical hydrocarbon technology, whereas geothermal energy is a sustainable and renewable energy resource.
An Enhanced Geothermal System is an underground reservoir that has been created or improved artificially. EG systems generate geothermal electricity without the need for natural convective hydrothermal resources. Until recently, geothermal power systems have exploited only resources where naturally occurring heat, water, and rock permeability are sufficient to allow energy extraction. However, by far the most geothermal energy within reach of conventional techniques is in dry and impermeable rock. EGS technologies enhance and/or create geothermal resources in this hot dry rock (HDR) through ‘hydraulic stimulation’.
Both EGS and shale gas extraction technologies have a shared objective: to use stimulation techniques based on the high pressure injection of water in order to extract as much mass flow as possible. However, the target is different, either heat or gas. Shale gas is locked in rocks,
typically with low permeability in sedimentary basins, in a dispersed form without fluid.
From what I have gathered, this application seems to be more popular and widespread in the European region, and not in the States. This may due to the fact that the permeability of rocks is insufficient enough to where the net energy is that of what we gain from solar panels and wind farms, which is relatively low compared to crude oil. Whether or not Europe is taking full advantage of these systems, it should be note worthy to apply some form of them here.