Binary ORC plants use heat exchange to exploit geothermal fluid to heat up and vaporize a secondary organic fluid that drives a turbine and produces electric power. In this way, the geothermal fluid remains within a closed loop of piping (from the reservoir to the reinjection) without passing through the turbine, with no harmful emissions into the atmosphere. The heat that is not converted into electricity can be delivered to a thermal user or dissipated through a suitable cooling system. ORC is very effective for exploiting resources with high steam fractions at locations where it is not convenient to collect and deliver all the fluids to a centralized station, but preferable to employ modular well-head units. Existing single-flash power plants can be improved by adding an ORC system on the separated brine stream, before reinjection. This makes it possible to produce more power from the same geothermal resource.