Advanced power cycles for enhancing geothermal sustainability 1,000 MW deployed worldwide

Until the early 80´s geothermal plants used steam turbines exclusively, operating on dry steam or separated steam. In the mid 80´s the was introduced, initially to enable exploitation of lower enthalpy resources, then to recover the heat from the separated water, and thereafter to handle high gas content resources as well as high enthalpy resources using combined steam/organic cycles [1]. Most of these plants are air-cooled, assuring 100% reinjection of geothermal fluids and thus enhancing sustainability as well as reducing the environmental impact. Today close to 1,000 MW of such plants are deployed worldwide. Examples of commercial plants are given in capacities from 200 kW to 130 MW.