After the completion of the 3 wells system in the previous years of the European HFR
Soultz project, improvement of the brine circulation to be established through the
underground heat-exchanger is under way, mainly by innovative chemical and hydraulic
stimulation of the crystalline rocks. In the mean time, the design of the future
power plant was investigated by integration of numeric modelling of the different
components. This power unit will include the brine circulation system consisting of
two extraction pumps, one long shaft and one electro-submersible pump, and one re-
injection pump at ground level.
The energy consumption for brine extraction and re-injection was computed from the
combination of the thermo-hydraulic Geowatt well model and well pumping modules.
As for the electric power production, Organic Rankine Cycle system with hydrocarbon
working fluid shows better efficiency than other conversion systems in connection
with the hot temperature expected at the inlet of the plant (175-185 °C) and with
the cold source available on site.
The expected energy balance of a demonstrative 1,5 MWelec ORC to be installed on
site will be presented in regard with different wells management hypothesis. Final
figures of real heat extraction will be fixed at the end of the long duration
thermal test of the heat-exchanger to start in the coming months.