"The project is identified as True Geothermal because all current geothermal projects require substantial amounts of water or steam as part of their power generation process," stated Jim McIntosh, GeoGenCo's CEO and COO, "and are therefore, more appropriately known as hydro-geothermal since water is a mandatory part of the geothermal process (either in the form of brine or steam) for both the extraction of heat and for the disposal of the residual brine."
True Geothermal does not utilise any water in its power generation process. Rather than extracting the geothermal fluids, a high-performance heat exchanger is inserted into an existing (but non-performing) geothermal well where only heat is extracted from the geothermal formation, not from water, brine or steam.
While a permit application for approximately six acre-feet of water has been filed, about one-third of this water will be utilised for dust control and the other two-thirds reserved for emergency fire-fighting purposes. Zero water will be utilised for the power generation process.
A geothermal plant can require an average of 800 to 1,000 acre-feet of water per MW per year. A 50MW geothermal power plant could, therefore, require between 40,000 and 50,000 acre-feet of water per year, which translates to between 13 and 16 billion gallons of water.
Such significant reductions are marked improvements for US states such as California, where reliable 24/7 energy such as geothermal is needed to meet Renewable Portfolio Standards goals. True Geothermal will directly coincide with California's law requiring 50 per cent of the state's power to come from alternative energy such as geothermal energy by 2050.
GeoGenCo's VP of engineering, Theodore Sumrall, explained: "GeoGenCo's non-water utilising geothermal power generation technology can also take advantage of previously drilled geothermal wells that are considered 'non-producing' due to factors such as insufficient heat, lack of brine or steam flow, or insufficient geo-pressure. This is not only a major cost-saving but also a major risk reduction benefit to the process."
While hydro geothermal power has the smallest land-use footprint of any renewable power (an average of 4.5 acres/MW or less than 10 per cent of solar power), True Geothermal has less than half the footprint of hydro geothermal.
GeoGenCo describes its technology as being an innovative, carbon-neutral production cycle power generation system which will help solve a host of problems associated with traditional hydro geothermal power generation resulting in geothermal becoming much more widely used.
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