The Geothermal Radial Outflow Turbine

Abstract

Geothermal energy exploitation for electric power production is possible by utilizing two main systems: Steam turbines and Organic Rankine cycle (ORC) binary power plants [1]. Whilst steam turbines with an axial configuration have traditionally been the technology of choice, the organic cycle possess the flexibility to be expanded utilizing axial, radial inflow or screw expanders. An innovative turbine configuration for geothermal applications was developed by the Italian turbine manufacturer EXERGY. The technology, known as the organic radial outflow turbine was designed, engineered, manufactured and tested in Italy. A 1 MWe geothermal organic Rankine cycle (ORC) equipped with the EXERGY radial outflow turbine has been in operation since early 2013. Despite other experimental ORC units tested in Italy previously, the patented EXERGY radial outflow turbine represents the first commercial geothermal organic turbine operating in Italy, and the world?s first operation of a radial outflow turbine in any ORC application. The turbine was delivered to ENEL Green Power and installed in the Bagnore geothermal site at Monte Amiata, Tuscany (Italy).