Project: Enhanced Geothermal Systems Review.
This CATF project, working with partner Energy Options Network (EON) ( http://www.energyoptionsnetwork.org) is looking to the future of geothermal energy, beyond today’s technologies. Today’s geothermal energy production relies on circulated hot groundwater (hydrothermal), such as at the Geysers geothermal field in California, and therefore hydrothermal applications are highly limited geographically. However, researchers and companies are taking geothermal energy to the next stage with “hot dry rock” (HDR) , which began with research efforts in the 1970s.
In HDR, injected water is circulated through engineered/naturally fractured rock and heated at depth and transported back to the surface through a production well to turbines generating electricity at the surface. There are a number of HDR pilot projects and testbeds, yet we are aware of no commercial examples of HDR.
If HDR can be successfully commercialized, and then the next step would be to combine HDR engineering with ultra deep drilling methods such as plasma drilling (which must be scaled up from the laboratory to the field), which would allow tapping into deep geothermal energy nearly anywhere in the world. The premise is that if wells can be drilled deep enough, supercritical water (temperature: 374 deg C, pressure 22 MPa) can be tapped into, then high-pressure turbines (such as at many of today’s newer coal plants) could be utilized to provide nearly an order of magnitude (10x) more energy than subcritical systems.These innovations would radicalize energy supply because they would allow widespread conversion from fossil energy (including retrofitting existing plants) to unlimited renewable geothermal energy–unlike today’s geothermal systems which must be located near areas of very high geothermal flux, usually near volcanic regions. The technology is currently only a vision, the various components in development stages. With this project, CATF is looking to better understand what innovations are needed to move supercritical geothermal hot dry rock forward from the laboratories into the demonstration and ultimately the commercialization stages.
The summer intern would conduct a comprehensive international literature review highlighting the state of the science, and significant worldwide projects in several areas for technological development. The goal would be to outline the state of the technological development in several areas, including: 1) deep subsurface geo-engineering/fracturing research & demonstration projects (e.g. the EGS COLLAB/SURF project) , 2) ultra-deep basement rock drilling tests and innovations (e.g. plasma, laser and other “spalling” techniques), and 3) supercritical water geothermal experiments and pilot projects (e.g. Iceland IGS) . The requested products are: A) an annotated literature review, B) a summary white paper in three chapters and C) –If the intern has the IT capabilities and interest–an online database. Timeframe for this could range from three or four weeks to an entire summer if the intern has interest and adequate time. The project need not be conducted at a CATF office.