The SERG group is active since many years in the field of improving the sustainability of Geothermal Energy Conversion. Proposals include geothermal/sola hybrid solutions, as well as advanced power cycles (ORC sub- and super-critical, Kalina, ...) and complete reinjection of Non-Condensable Gases in the geothermal reservoir ("Zero Emission"). A short summary is linked.
A research paper, published in Nov. 2015 on Sustainability (MDPI; special issue on Sustainability of Energy Conversion), http://www.mdpi.com/journal/sustainability, reports on a case study for Monte Amiata, Italy. Different solutions for hybridization of a flash geothermal power plant with an ORC are analyzed from the point of view of environmental performance, arriving to evaluation of the issue of total reinjection of the Non-Condensible Gases.
This work was perfomed following a student placement of one of the authors, Lorenzo Bruscoli, at ENEL GreenPower (Pisa), which gently provided the fundamental data of the power plant.