Rigorous thermodynamic models are crucial to understanding the properties of geofluids, as part of planning for exploration, design and operation of geothermal energy facilities. However, these models are currently incomplete and do not give accurate enough results for reliable planning; Operators commonly need to carry out empirical, site-specific trials instead, which are costly and occur ‘after the fact’, reducing their effectiveness. The GEOPRO project will produce a set of integrated knowledge based design and operation tools to allow the geothermal industry to explore, design and operate systems more effectively, reducing the LCOE to competitive levels. To do this, we will firstly generate new experimentally derived datasets to fill gaps in current knowledge of the heat and mass transfer behaviour of complex and highly concentrated fluids under hot and superhot conditions. These will provide next-generation equations of state, which we incorporate into a set of operation and exploration tools. To address these objectives, we have assembled a consortium that combines excellent strength in all areas from the systematic and accurate experimental determination of fluid properties through beyond-industry standard reservoir modeling to process optimization and flow assurance modeling. Our consortium also contains geothermal industry partners, on whose sites we will verify the accuracy of the toolsets. We will then incorporate these into open-access knowledge base for use and development across the industry. The geothermal industry will use these new tools to benefit from: the capability to better explore and ‘vector in’ on new resources; the ability to predict the return on a well more reliably for investment decisions; control-oriented simulations to reduce the engineering overkill currently required; improved energy extraction through knowledge of the real production constraints.