EASYGO graduates will be the first generation of multidisciplinary experts with a standardized education in geothermal operations. Their research results have a direct impact on society and economy. An efficient and safe supply in the future is identified as a strong societal demand. Three different approaches are used to obtain data and knowledge: field measurements, laboratory experiments, and numerical simulation.
“How do we run geothermal systems efficiently?”
A database has been developed based on field data on hydrogeochemical properties of geothermal reservoirs in the Netherlands. It systemizes the current knowledge, makes it openly accessible, and increases the possibilities of using geothermal energy in the Netherlands for upcoming projects, e.g. the Delft Adwarmte Project. Additionally, high-resolution outcrop models were obtained using unmanned aerial vehicle-based digital photogrammetric data. The data are used to build models that allow the identification of discontinuities and related subsurface fluid flow. Also, laboratory experiments can bring relevant information. A novel laboratory-scale pilot test of CO2-based geothermal energy investigates the permeability evolution and chemical performance of a CO2-based geothermal reservoir under elevated pressure and temperature conditions. Modeling these data with a focus on thermo-hydro-mechanical processes shows that lower injection temperatures can induce thermal fractures that can impact the near-borehole conductivity and injectivity. An integrating numerical simulation approach, which combines geophysical data and geo-models allows updating the model's geometry while also calculating its geophysical properties within the lithological units. At the surface, geothermal power plants can be optimized by using a different secondary fluid for heat extraction. Steady-state cycle computations and optimization algorithms have been used to find zeotropic mixtures as optimal working fluids for binary power plants due to their non-isothermal phase change. Also, minimizing the average temperature difference between the geofluid and cycle working fluid is a key object for the design of the heat introduction system, in order to achieve high overall conversion efficiency.
“How do we run geothermal systems safely?”
Advanced and integrated monitoring concepts have been developed to observe and measure processes in the subsurface prior to and during decades of operation. A controlled-source electromagnetic monitoring survey has been tested to detect small resistivity changes as expected for a deep low-enthalpy reservoir. Small resistivity changes are caused by the replacement of the original hot water in the underground with cold water. Seismic events associated with the injection and extraction of water in geothermal reservoirs have been studied using long-term seismic monitoring. To understand the reason and source of seismic events fracture patterns in the subsurface have to be studied in detail. Seismic monitoring combined with GPR measurements have been proven to be optimal for monitoring, especially CO2 based systems. Existing databases have been used to study cooling induced stress changes on the laboratory, medium and full reservoir scale. Monte-Carlo simulations and machine learning is used to provide real-time analysis of data during operation. All these advancements will ensure safe operations with no adverse impacts on workers in the industry or on the wider society.
