Geothermal power generation is the only economic renewable energy class that can be deployed on a wide scale.
That being said, investors should know that subsurface teams have the transferable skills to work on both conventional hydrocarbon reservoirs and apply the same knowledge to high enthalpy geothermal developments. Essentially the only difference is in the reservoir engineering analysis, which in oil&gas deals with dual phase flow, relative permeabilities, fluid PVT and material balance.
Finding geologies with optimal conditions helps in advancing project economics. So, from a viability point of view, high-temperature high-permeability sedimentary structures (or fractured igneous rocks) at shallow depths will be preferred.
From a private equity point of view, such projects should be developed and sold to power companies in order to have the shortest payback time.