Increasing heat recovery is challenging for the geothermal projects in the Upper Rhine Graben (URG). In the framework of the H2020 project MEET, several studies about the thermal effect on the Soultz-sous-Forêts power plant and its deep wells are being conducted. The main goal is to improve the thermal power production and optimize the fractured granitic reservoir while minimising environmental issues. At the Soultz plant, the reinjection at 70°C leads to a well-known scaling formation in the heat exchanger due to the chemistry of the brine and the thermodynamic changes. Barium, sulphates and metalrich sulphides precipitate in the surface installation. Since early 2019, an operating heat exchanger system able to exploit reinjection temperature from 70°C to 40°C is tested in the power plant. This heat exchanger was designed to cool down about 10% of the nominal mass flow of the Soultz geothermal plant. Dissolved gases and high salinity of the Soultz brine have led to corrosion issues. The heat exchanger was designed with several tubes alloy in order to determine the best trade-off between corrosion resistance in Upper Rhine Graben conditions and economical aspect. This alloy selection will also assess the impact of metallurgy corrosion on scales. In case of successful results with the prototype, a small scale ORC will be designed and tested at Soultz-sous-Forêts to generate electricity with full flow and at low temperature.