Geothermal Alternative Thermoelectric Electricity Regeneration

The DOEs Office of Energy Efficiency and Renewable Energy (EERE) is seeking to support the development of innovative technologies (not conventional Rankine or binary cycle devices) to efficiently generate electricity from geothermal heat and fluid resources with lower capital, operating, and maintenance costs, while improving other key performance factors. Common problems associated with geothermal heat and fluid sources are low temperature potential and high mineral content, which affect the efficiency of geothermal plants, especially in the summer, and also affect the costs of equipment and maintenance. Physical Optics Corporation (POC) proposes to develop a new Geothermal Alternative Thermoelectric Electricity Regeneration (GATER) technology based on generation of thermoelectric power directly in the geothermal well by the diffusion of protons in nanoporous structures under a temperature gradient. Instead of pumping geothermal fluid to the surface, extracting heat, and subsequently returning the fluid to the ground, the GATER modules are installed directly in the geothermal well and require cooling only by the circulation of cold water or by the phase-change closed-circuit thermo siphon, which uses gravity both to bring vapor up to the external condenser and to return the condensate. Commercial Applications and Other Benefits GATER modules can be used in far-ranging geothermal resources due to their ability to recover and convert heat to electricity from large, complex areas with low thermal potential. GATER applications fall into three categories: Low-temperature geothermal resources, where heat is not currently recoverable using standard geothermal techniques. Extremely aggressive geothermal fluid, where contact with the fluid is limited to a compact, possibly ceramic, heat exchanger installed in the down hole. Cost-effective geothermal power generation when a local source of cold water is available to provide cooling for the GATER module.