The EU H2020 MEET project (Multidisciplinary and multi-context demonstration of Enhanced Geothermal Systems exploration and exploitation techniques and potentials), aims at demonstrating Enhanced Geothermal Systems (EGS) in different geological environments throughout Europe at an economically sustainable level. The consortium includes a total of 16 partners including eight industrials, two applied research institutes and six universities from five different European countries. The main project goals are a) to gather knowledge of EGS heat and power production in various geological settings, in particular Variscan metamorphic and magmatic rocks, b) to increase heat production from existing plants and to convert oil wells into geothermal wells, c) to enhance heat-to-power conversion at low temperature (60-90 °C) by using smart mobile Organic Rankine Cycle (ORC) units, and (d) to replicate the technology thus promoting the market penetration of EGS power and/or heat plants. Within this context, in GFZ Sections 4.2 and 4.8, we are experimentally studying the long term behavior of fractures in reservoir rock in terms of fracture permeability evolution and sustainability upon actions of stress, temperature, and chemical interactions.