Enhanced geothermal systems (EGSs) allow the enormous untapped potential of geothermal energy to be put to widespread use. EGS measures are generally intended to improve the productivity (or injectivity) of a geothermal reservoir by increasing the overall transmissivity of the reservoir rocks. This goal can be achieved by various methods that are dependent on the geological system, comprising the rocks, the rock structures, the tectonic situation as well as the stress field.
To demonstrate the DESTRESS concept, four different sites with access to a reservoir by means of geothermal wells have been chosen (Haute-Sorne, Soultz-sous Forêts, Rittershoffen, Mezöberény). As their development is subject to a number of uncertainties, three fallback options have been identified in case of unforeseen situations such as problems with the well drilling: one site offering sedimentary and basement rock in a single system in Groß Schönebeck, Germany; one site with a deep sandstone aquifer in Middenmeer, the Netherlands; and a last site in Bedretto, Switzerland, that was added very recently in September 2018. Additionally, a new site is planned in Geldinganes, Iceland.