This study reveals new insights to the behaviour of subsurface water flow in fractured bedrock which has important implications for environmental safety of geological storage of spent nuclear fuel, carbon sequestration and other unwanted substances. It shows the relevance of accounting for small scale fracture heterogeneity in models to make accurate predictions on the transit times and pathways water flow takes through bedrock.

The Iceland Deep Drilling Project (IDDP) aims to investigate utilization of supercritical fluids. These fluids are considered to provide 10x more energy compared to conventional geothermal wells. During the IDDP-2 well stimulation, casing at about 2300 m depth was damaged and therefore the discharging fluid comes mainly from this depth instead of depths at higher temperature. The chemical composition of the discharge is, however, indicating minor contribution from the deeper depths.

Energy systems across the globe are evolving to meet climate mitigation targets. This requires rapid reductions in fossil fuel use and much more renewable generation. Renewable energy is dependent on the weather. A consequence of this is that there will be periods of low renewable energy production, driven by particular weather conditions. We look at the weather conditions during these periods and show the Indian energy sector could prepare for these events out to 14 days ahead.

We develop a simplified model which describes the geological geometry of the Vendenheim site, the solid and fluid properties were adapted from studies in the area. We implement compute the hydrothermal flow with a temperature dependent density and viscosity in a porous medium, in order to verify if a hydrothermal convective system is compatible with known observations at the Vendenheim site, and to get a better idea of the initial conditions of a model for an induced seismicity model. 

Concepts of High-Temperature Aquifer Thermal Energy Storage (HT-ATES) are investigated for system application in the German Molasse Basin. We quantify via physics-based numerical modelling the system performance with respect to HT-ATES concept development and provide a predictive analysis of HT-ATES application in the Upper Jurassic reservoir. Results demonstrate a non-uniform layer-specific distribution of the thermal front propagation, while promising heat recovery efficiencies are predicted.

Storm Daria was a severe winter storm that crossed northern Europe on 25–26 January 1990 with large damage costs and fatalities.  A literature review is presented of societal damage and the interruption of energy and transport networks.  Met-ocean data is analyzed to see if there might have been rogue wave strikes in the North Sea.  This includes careful analysis of tide gauge data from stations around the North Sea as well as available offshore wave measurements and maritime accidents.   

Future glaciations can affect the long-term safety of deep geological repositories for nuclear waste. This study introduces a simple method to assess frequency and duration of ice sheets over the next one million years at locations with past glaciations. The method considers uncertainties in human-caused CO₂ emissions and climate change. It is easy to implement for any nuclear waste management organization that need to consider impacts of future ice sheets on long-term safety.

We examined how water quality in aquifers and streams varies along the Besòs catchment, and changes in streams during wet and dry periods. Analysis of water quality data (2013-2023) in open databases shows nutrients and salinity increase towards the outlet, and more markedly during dry periods. Since such dry periods may become more frequent with climate change in this Mediterranean basin, this highlights the importance of controlling pollution sources affecting water quality and availability.

Dealing with the sociotechnical system of nuclear waste needs an integrated perspective. Its global blockage is due to the neglect of relevant issues. The concept of sustainability (passive protection & control) suggests itself as a reference, enabling a stepwise analysis of dimensions: beyond the triad of ecological/economical/social, also temporal, spatial, technical, political, ethical. The proposal avoids simple complexity reduction, either “technical” or “social fix” (volunteers first). 

This paper presents a surrogate modelling approach applied to a geochemical system of uranium sorption on clay, relevant for the safety assessment of nuclear waste repositories. The surrogate uses knowledge about the underlying process to recursively partition the dataset into regions of reduced dimensionality. It achieves high accuracy with a competitive prediction throughput, and is a promising method to speedup  computationally demanding coupled reactive transport models.

To operate aquifer thermal energy storages in a sustainable way, we located an artesian aquifer other than the aquifer storage in a research wellbore by analyzing the subsurface temperature as monitored with a fiber optic cable in three artesian flow tests. The positioning of the artesian aquifer was validated via numerical modelling. Analyses of the temperature data and numerical modelling enabled determining the profile of flow velocity, flow rate and the depth interval of inflow.

To combat global warming and achieve net-zero CO₂ emissions by 2050, Carbon Capture and Storage (CCS) is vital. Despite being a top CO₂ emitter globally, Brazil is early in its CCS journey. Our study evaluates the potential of using southern Brazil's saline aquifers for CO₂ storage with the aim of supporting Brazil’s efforts to reduce emissions and mitigate climate change. We identify optimal storage sites in two basins, Paraná and Espírito Santo, with ideal locations near existing pipelines. 

As groundwater serves as the principal source of water worldwide, its quality is of paramount importance. In this study, the evolution of groundwater quality in California is assessed using the Water Quality Index & Weighted Index Overlay Analysis methods. Several water quality parameters are considered for the analysis, and the results from both methods are compared. The study shows that in most parts of California, groundwater quality is potable, as per WHO guidelines, except in a few places. 

In Colombia there are many areas with little or no hydrometeorological information that would allow for adequate water resource management, especially in times of low supply of the resource. In this work, several modeling techniques are implemented to generate data grids of meteorological variables that allow for reliable calculations of the potential recharge of aquifers, controlling uncertainties.