The low-temperature resources are widely used for direct heat use and for generating electricity using binary technology. 72 countries utilize geothermal energy for direct use, accounting for over 76 TWh a year in usage. Space heating is the most common direct application.
Binary technology utilizes a working fluid with a lower boiling point than water to run the turbine. Common binary cycles include the Organic Rankine Cycle and the Kalina cycle.
Enhanced Geothermal Systems is a term of reference for a new technology appropriate in resources of high temperatures that have limited amounts of fluids. It involves depositing water, waiting for the resource to heat it, and then extracting it to a flash or binary plant. Although there are a few commercial projects now under development, the technology's use has increased risks. Once mastered, it could easily triple the global potential for geothermal electricity production.
Despite the maturity of geothermal technology, there is ongoing research on the improvement of existing technologies as well as the active development of new ones.
