OPENING THE TAP ON HYDROTHERMAL ENERGY.

Half our identified hydrothermal resources are simply not hot enough to make electricity by conventional geothermal technology. The Heber plant in southern California is demonstrating a binary-cycle approach that is custom-made for generating power from these medium-temperature brines. This paper discusses several important technological innovations which have been incorporated into the Heber plant and are demonstrating their readiness for utility application in the near future. They include the world's largest hydrocarbon turbine, 'floating' cooling system and the use of a hydrocarbon working fluid mixture that was specially selected to match the thermodynamic characteristics of the hydrothermal resource and the site's ambient temperatures.