GeoThermal - Hydroelectric Energy
GeoThermal energy along with hydroelectric are the only renewable energy sources that operate on a 24/7 basis. Intermittent energy generation from other renewables places a significant burden and need for new and large capacity energy storage schemes for electicial load balancing on a power grid. GeoThermal energy is generally located in ideal locations to utilize the existing formation permeability and natural geofluids for the power generation. Alternative geothermal systems have been reseached since the early 70's especially hot dry rock as a geothermal source. The hot low permeable hot rock is conventional fractured with invasive fluids and thus the potential for induced seismicity can be significant. An example is the geothermal scheme in Basel, Switzerland, which has been shut down due to induced seismicity.
An alternative GeoThermal energy source is the hot ductile formations in sedimentary basins, that exist close to infrastructure in the USA. Highly permeable inclusions can be installed in these ductile formations by the injection of a non-invasive fluid and proppant, without giving rise to any potential induced seismicity. The system could be a single well with multiple azimuth propped vertical planes, or interconnected wells. In this latter case the geothermal wells are hydraulically connected by the highly permeable installed vertical planes. A closed cycle supercritical carbon dioxide loop is used as the thermal energy transfer medium for electrical power generation, The system has considerable advantages both economically and environmentally, especially its 24/7 electrical generation capability, close to infrastructure, and with construction and operation being minimally invasive and a small surface footprint.
Clearly a pilot is required to test the limits of the inclusion propagation and its coalescense between wells if needed. There are extensive hot ductile formations in sedimentrary basins throughout the USA, especially in the southern San Joaquin basin in southern California.