The GEMex project is a complementary effort of a European consortium with a corresponding consortium from Mexico, who submitted an equivalent proposal for cooperation. The joint effort is based on three pillars: 1 – Resource assessment at two unconventional geothermal sites, for EGS development at Acoculco and for a super-hot resource near Los Humeros. This part will focus on understanding the tectonic evolution, the fracture distribution and hydrogeology of the respective region, and on predicting in-situ stresses and temperatures at depth. 2 – Reservoir characterization using techniques and approaches developed at conventional geothermal sites, including novel geophysical and geological methods to be tested and refined for their application at the two project sites: passive seismic data will be used to apply ambient noise correlation methods, and to study anisotropy by coupling surface and volume waves; newly collected electromagnetic data will be used for joint inversion with the seismic data. For the interpretation of these data, high-pressure/ high-temperature laboratory experiments will be performed to derive the parameters determined on rock samples from Mexico or equivalent materials. 3 – Concepts for Site Development: all existing and newly collected information will be applied to define drill paths, to recommend a design for well completion including suitable material selection, and to investigate optimum stimulation and operation procedures for safe and economic exploitation with control of undesired side effects. These steps will include appropriate measures and recommendations for public acceptance and outreach as well as for the monitoring and control of environmental impact. The consortium was formed from the EERA joint programme of geothermal energy in regular and long-time communication with the partners from Mexico. That way a close interaction of the two consortia is guaranteed and will continue beyond the duration of the project.