Soultz-sous-Forêts, France

This pilot EGS project is located within the Upper Rhine Graben. Five deep boreholes (3.6 to 5 km deep) have been drilled in fractured crystalline rocks. Several hydraulic and chemical stimulations have been carried out for improving the initial injectivities or productivities of the 5 km deep reservoir. Long term hydraulic tests have been done and proved the hydraulic performances of the deep-seated fractured granite. An Organic Rankine Cycle (ORC) binary plant has been built in 2008 but due to severe corrosion issues related to the salinity of the natural brine a full renovation of the surface geothermal installations was required (Scheiber at al., 2015). A new geothermal power plant was installed and was commissioned in August 2016. In the framework of the DESTRESS project, it is planned to evaluate the impact of soft treatments on injectivity index during long term exploitation. Thus, specific chemical treatments for injectivity improvement, downhole logging as well as relevant monitoring can be performed at this geothermal site for longterm circulation.

Operator operator-logo

Operator of Soultz-sous-Forêts: és Géothermie

Responsible DESTRESS-Partner: EOST, Université de Strasbourg 

Work Package No



Soultz-sous-Forêts, France

Construction Year

2008 (1st power plant) and 2016 (2nd power plant – currently in operation)

Foreseen Stimulation Techniques stimulation-logo

Core treatment, injection tests in GPK4

Type of Use

ORC: 1.5 MWe gross power

Soil Condition

Fractured granite with high temperature geothermal resources

Production Horizon

Carboniferous fractured granite

Upper Depth (m)


Thickness (m)


T (°C)


Salinity (g/l)



Clément Baujard
Ingénieur réservoir / Reservoir Engineer
ÉS Géothermie
26 boulevard du Président Wilson 67000 STRASBOURG
Bureau: Bâtiment Le Belem, 5 rue de Lisbonne, 67300 SCHILTIGHEIM
Tél: +33 (0)3 88 20 72 97

Yann Lucas 
Gerhard Schäfer
EOST École et Observatoire des Sciences de la Terre
Université de Strasbourg et CNRS
Bâtiment Blessig
1, rue Blessig
67084 Strasbourg, France