European Geothermal Congress 2019 Den Haag, The Netherlands, 11-14 June 2019 1 GEMex: Cooperation in Geothermal energy research Europe-Mexico for development of Enhanced Geothermal Systems and Superhot Geothermal Systems David Bruhn 1,2 , Egbert Jolie 1 , Katrin Kieling 1 , Eugenio Trumpy 3 . Damien Bonté 4 , Domenico Liotta 5 , Gylfi Páll Hersir 6 , Paromita Deb 7 , Jan Diederik van Wees 8 , Ernst Huenges 1 1 GFZHelmholtz Center Potsdam GFZ; Potsdam, Germany, 2 Technical University of Delft, Delft, Netherlands, 3 CNR- IGG, Pisa, Italy, 4 Utrecht University, Netherlands, 5 University of Bari, Italy, 6 ÍSOR-Iceland Geosurvey, Reykjavík, Iceland, 7 E.ON Energy Research Center, RWTH Aachen, Germany, 8 TNO, Utrecht, Netherlands dbruhn@gfz-potsdam.de Keywords: Exploration, EGS, superhot geothermal systems, international cooperation ABSTRACT A focus of European research cooperation in the last years has been on developing concepts for the exploitation of unconventional geothermal resources such as Enhanced Geothermal Systems (EGS) or, more recently, Superhot Geothermal Systems (SHGS), including those with supercritical water. One such project addressing unconventional geothermal systems is the international cooperation between Europe and Mexico GEMex (Cooperation in Geothermal energy research Europe-Mexico for development of Enhanced Geothermal Systems and Superhot Geothermal Systems). The cooperation encompasses two partner projects, one funded within H2020 and one by the government of Mexico through the National Council of Science and Technology CONACyT. The projects are designed to explore two specific sites to develop concepts for their utilization as EGS and SHGS. The site for EGS development is the Acoculco crater, SHGS are investigated at Los Humeros, both in the eastern Trans-Mexican Volcanic Belt. Los Humeros is currently exploited with steam temperatures reaching up to 340°C. In some wells, temperatures higher than 380°C were inferred, but these are not currently used for energy conversion. The system feeding these super- hot wells is the target of GEMex investigations on SHGS. Acoculco is not currently exploited, but was the target of two 2km deep and 300°C hot wells that did not encounter any fluids, despite some surface manifestations indicating the presence of a hydrothermal resource. The cooperation is supported through two partner projects, one funded by the government of Mexico and one through H2020, both called GEMex. Project start was in October 2016. The approach chosen for the cooperation on the two sites encompasses the entire development chain from resource assessment to detailed exploration, reservoir modelling and concepts for the exploitation of the unconventional geothermal resource. In this approach, the projects build strongly on previous and ongoing EU funded projects that addressed advanced and integrated exploration methods as well as drilling and developing superhot geothermal resources and advanced EGS concepts. The progress reached at both test sites will be reported at the EGC2019. 1. INTRODUCTION – STUDY SITES 1.1 Los Humeros Los Humeros is a Quaternary volcanic complex with existing geothermal power plant facilities (Installed capacity 95.7MWe, from ~ 30 producing wells), developed and operated by the Comisión Federal de Electricidad (CFE). The focus within GEMex is on (1) an improved and comprehensive understanding of the location and characteristics of the deep superhot geothermal reservoir (SHGS), (2) its connection to the known conventional system based on a complementary, interdisciplinary approach of novel and established exploration and resource assessment methods, and (3) on concepts for the development of the superhot geothermal resource. Los Humeros is a system with reservoir temperatures > 380°C (> 2 km depth); however, due to the aggressive physicochemical characteristics of the geothermal fluids, a sustainable operation at superhot conditions has not yet been fully manageable for power generation. 1.2 Acoculco Caldera Preliminary geological studies consider the Pliocene- Pleistocene Volcanic Complex of Acoculco a candidate for application of EGS technology. Focus within GEMex is on (1) an improved characterization of the geothermal system, (2) an evaluation if application of EGS technologies can hydraulically connect existing