The rate and magnitude of conductive and advective thermal processes that control the efficiency and sustainability of mine water geothermal and thermal energy storage are poorly quantified. We present results of multiphysical observations collected during a 25-day heat extraction experiment performed on an abstraction–reinjection mine water well doublet at the UK Geoenergy Observatory in Glasgow. The results showed how the thermal plume generated by injection of cool water developed from the injection borehole, mainly driven by advection at the level of mine workings. Heat conduction around the cased part of the injection borehole resulted in different cooling rates related to lithological variations, clearly shown in the distribute temperature sensing data. The electrical resistivity tomography monitoring provided a time-lapse image of the evolution of the cool plume, which extended laterally within the mine workings to pass a borehole located at 10 m away in less than 2 days, and later above the mine workings into the bedrock. It also showed how the effects of cooling remained for at least 18 days after the injection stopped, providing new insight into thermal storage behaviour of mine water systems. The results provide an unprecedented opportunity to visualize the effects of geothermal operation in mine water settings and are useful guidance for project developers and regulators.

Heat transfer rates are critical to underground heat storage recovery potential and sustainability of thermal abstraction for heating and cooling buildings. A 17-day heat injection - abstraction experiment into a flooded, disused mine working was conducted at the UK Geoenergy Observatory in Glasgow. Analysis of the thermal response of different lithologies intersected by an injection borehole during and after a heat injection experiment is used to quantify the heat exchange between rock mass and circulating mine water. The monitoring data from Distributed Temperature Sensing (DTS) has been analysed and numerical models using COMSOL Multiphysics were developed to characterise the rates and controls on thermal processes during heat injection and recovery. The results suggest the key control of the borehole construction on the temperature change in the first 10 hour of heat injection. In the long term, the thermal response mainly depends on the thermal conductivity of the lithologies. The radial heat transfer reaches a steady charging rate of 23 W/m2 and 16 W/m2 in the sandstone and clay intervals, respectively, and a maximum of 14 W/m2 and 10 W/m2 at the start of recovery. This is accompanied by upward heat diffusion/convection from the mine working. This study demonstrates the ability of DTS to identify lithological heterogeneities at a high resolution, and the importance of considering the overburden structure and lithology for thermal storage applications.

The design of ground-source heat pump systems depends on reliable determination of heat transport parameters, especially the ground thermal conductivity. An effective thermal conductivity, lambda eff, is traditionally calculated from in-situ thermal response testing (TRT), expressed as a bulk value for the depth range being tested. However, this practice is insensitive to heterogeneous heat transport within the ground, and flowing groundwater may significantly increase lambda eff. To characterise high- and/or heterogeneous-flow regimes, e.g. in fractured aquifers, distributed TRT observations are advantageous. Distributed TRTs using fibre-optic distributed temperature sensing (FO-DTS) have therefore been applied at a chalk site (Berkshire, southern UK) to assess heat flow and the depth variability of effective thermal conductivity and flow conditions, within boreholes reaching up to 100 m depth. With a vertical resolution of 0.5 m, FO-DTS can isolate different thermo-hydrogeological conditions in the chalk and particularly the groundwater flow horizons. Values of lambda eff, measured during a 3-day TRT, vary with depth between 5 and 30 W/m K, compared to thermal conductivities of 2.3-2.9 W/m K measured on chalk core samples. Zones of enhanced lambda eff correlate with highly permeable flow zones in the aquifer. However, when evaluated during a 7-day cooling phase, lambda eff is reduced by between 10-60% compared to values measured during heating, highlighting the potential influence of complex convection effects and vertical flow within the open borehole. Overall, this study illustrates the value of distributed spatial assessments of thermo-hydrogeological conditions, and the necessity of combining different testing approaches to characterise heat flow in dualporosity aquifers.

Flooded disused mines have significant potential to supply clean heating and cooling and for seasonal storage in areas that could continue benefiting from the mines after closure. A proved technology, a more widespread deployment of mine water geothermal development is hampered by technical, socio-economical, and regulatory challenges. Among the technical challenges, the long-term system behaviour is an uncertain but fundamental element, regarding both the groundwater flow and heat distribution in the subsurface aquifer and the optimal performance of the geothermal installation and its components. A further development of mine water geothermal requires information and data from pilot, commercial and research installations to improve the knowledge about these complex systems, understand the interaction with the surrounding environment and learn from the experiences towards a more optimal design and construction of the geothermal infrastructure. The UK Geoenergy Observatory (UKGEOS) in Glasgow was built between 2019 and 2023 as an at-scale research facility to study mine water geothermal. The observatory includes five boreholes drilled and screened into two levels of mine workings, four of them equipped with pumps and valves to allow for multiple configurations of abstraction and reinjection with operational pumping rates up to 12 l/s. The mine water boreholes are also equipped with hybrid fibre-optic cables for distributed temperature sensing (DTS) and electrical resistivity tomography (ERT) sensor arrays. The monitoring capabilities are complimented with an additional non-screened mine borehole, also equipped with DTS and ERT, and five environmental boreholes screened into the bedrock and the superficial aquifer to monitor the hydrogeological and thermal responses in the surrounding aquifers. The geothermal installation includes a sealed pipe between the abstraction/reinjection boreholes, three heat exchangers that can be used independently to test their performance, and a 200-kW heat pump/chiller. The system is equipped with sensors in the geothermal pipe circuit, the wellhead and downhole for high temporal resolution monitoring of hydraulic and thermal changes during the use of the Observatory and under natural conditions. In this work we present results from some of the first geothermal tests performed in the Observatory in 2023. These include abstraction-reinjection in both heating and cooling modes with multiple configurations and variable flow rates and reinjection temperatures taking advantage of the capabilities of the Observatory. The datasets have been processed and examined with the support of numerical modelling. The analysis of hydraulic and thermal data from the multiple sensors in the mine and monitoring boreholes, the DTS and ERT, and the geothermal installation before and after heat exchange and reinjection have provided further insights about short- and long-term responses of the system. The observations show the different temporal and spatial scales of the hydraulic and thermal responses to the use of the geothermal infrastructure that constitute valuable information for the design of new geothermal installations in disused mines. The Observatory is now operative and open to academic and research projects aiming to understand better mine water systems.

Urban geothermal solutions to heating and cooling have developed slowly in the UK, partly due to limited understanding of subsurface heat flow regimes and how stored heat might be sustainably governed within heterogeneous aquifers. Understanding heat flow through various aquifers is the goal of the SmartRes project, in which heat flow trials will be conducted in a number of sites. To provide context for heat flow experiments in a fractured chalk aquifer, geophysical surveys were acquired at Trumplett’s Farm, a groundwater abstraction and monitoring site near Reading (Berkshire, UK). Here, groundwater flow is primarily within a fracture network, likely in an active zone within the upper 10 m of the saturated chalk. Seismic surveys recorded energy generated with an impact source at surface geophones (24 cabled GEODE, and 20 nodal Smart-Solo, geophones) and hydrophone strings, deployed to 100 m depth in boreholes drilled at the site. Smart-Solo nodes were deployed in a ~10 x 5 m grid at the site, with cabled geophones occupying lines between adjacent boreholes, with geophone intervals of up to 2 m. Nodal geophones recorded passively throughout the 3-day deployment and will be analysed using ambient noise correlation to evaluate anisotropy. The remaining data has been used for preliminary analysis with MASW (Multichannel Analysis of Surface Waves), P-wave refraction velocities, and vertical seismic profiles (VSPs). MASW analyses suggest shear wave velocity (Vs) ranges from 250-600 m/s in the uppermost 1.5 m, but estimates are challenging given poor dispersion imaging of the fundamental mode. Different source-receiver offsets were tested to eliminate mode superposition, but the best dispersion curves are observed for zero-offset shots. Data were processed in a commercially available software with relatively limited freedom to adjust inversion parameters, hence further analysis will use the MuLTI code to undertake a constrained Monte Carlo inversion approach. The deeper structure of the chalk was characterised in VSPs, indicating reflective P-wave horizons at 52 and 69 m depth, separating material with interval velocities of ~2100 m/s, ~2500 m/s and 3000 m/s. Observing these reflections required aggressive frequency-wavenumber filtering to suppress direct waves in the water column. Electrical resistivity tomography (ERT) surveys were conducted using the BGS PRIME ERT system to optimise array configuration for long-term monitoring. The reconnaissance survey included in-hole, borehole-to-surface, and surface ERT at 1 m intervals, employing C1P1-C2P2 bipole-bipole and dipole-dipole arrays around the site. Preliminary ERT inversion revealed low resistivity zones within the top 1.5 – 2 m across the site and mapped a potential south-dipping high resistivity structure. A longer ERT survey spread is planned to better reveal hydrodynamic interactions at deeper depths. This initial insight will be refined with a fibre-optic distributed acoustic sensing deployment at the Trumplett’s site and an optimised repeat of the BGS PRIME ERT array. These will be synchronous with a thermal response test at the Trumplett’s site monitored with distributed temperature sensing. Keywords: Seismic analysis, ERT, geothermal investigation, fractured aquifer, aquifer thermal energy storage

The intensive exploitation of urban aquifers by shallow geothermal systems can affect the thermal balance of urban aquifers, thus reducing their renewability. This paper proposes a new management strategy for the sustainable use of shallow geothermal energy resources, based on imposing new constraints related to system exploitation regimes. To achieve this objective, a novel methodology was introduced for optimizing the operation of geothermal systems, by adjusting the flow rate and/or temperature change to maintain the existing thermal energy demand. The methodology was applied to a 1.8 million real operational data set from 24 shallow groundwater heat pump systems (GWHP), which are large and medium scale systems. The investigated GWHPs are located in five European cities. Two management alternatives for the optimization of geothermal energy resources use are presented in this work: (1) prioritizing higher flow rates over lower temperature changes, which tended to relatively decrease the discharge temperature by 1.48 degrees C on average, and (2) prioritizing higher temperature changes over lower flow rates, which tended to relatively decrease flow rates down to 8.09 L s-1 on average. The results show that GWHPs operating in European cities with the highest thermal power demand and flow rates achieved the highest flow rate reduction.

Heating and Cooling constitute a major part of society’s final energy use and a significant contributor to greenhouse gas emissions. The world society ought to mitigate climate change through decarbonisation, which must include the transition to low-temperature, sustainable and renewable heating and cooling technologies. Shallow Geothermal Energy is one of the most energy efficient and least greenhouse gas emitting available alternatives to provide space heating and cooling. The decarbonisation of the heating and cooling sector may have to comprise both individual systems and shared electrified heating and cooling systems from renewable sources of energy, where economies of scale and synergies between different types of consumers can be exploited. To this end, the focus of this paper is on the integration of shallow geothermal energy technologies into district heating and cooling systems. A key contribution of this work is the illustration of a number of practical case studies, highlighting the potential of existing shallow geothermal systems for DHC networks, which, as front runners in adopting such technologies, serve as paradigms for future development. Follows a discussion providing an outlook over the next 25 years. All in all, the future of utilizing shallow geothermal energy for district heating and cooling seems to be promising to play a pivotal role in sustainable urban development and decarbonizing the heating and cooling sector.

Nearly 40% of Europe's total energy consumption is dedicated to buildings and heating/cooling make a significant part of this consumption. Groundwater heat pumps (GWHP) are highly efficient, and low-carbon technology that can supply heating/cooling to buildings on small or large scales. Thus, they contribute to achieving European targets of net-zero greenhouse gas emissions by 2050. In the literature, studies on the utilisation of GWHP at a district scale, particularly in chalk aquifers, are relatively rare. The implementation of district-scale geothermal heat pump (GWHP) systems poses several challenges, including dealing with the scale and complexity of the systems, addressing geological variability, managing high initial investments, balancing energy demand and supply, ensuring proper maintenance and monitoring, and mitigating potential environmental impacts. These challenges require careful consideration and strategic planning to ensure the successful deployment and sustainable operation of these systems., This study numerically investigates a district-scale GWHP system and analyses the thermal plume development created due to the heating operation, offering insights into system performance. A good match was found between field results and simulation results for water level increase and drawdown. However, there is a difference of approximately 11% in system efficiency between field tests and simulations due to the lower abstraction temperature detected in the simulation. The simulation results show that cooler water injection into the fractured chalk aquifer creates a thermal plume radially spanning out to 50 m. The thermal plume has no effect on the abstraction temperature and system performance. This result can be attributed to the large distance between injection and abstraction wells and the low hydraulic gradient.

Re-use of the UK's coal mine water heating, cooling and thermal storage resource is increasing in scale and the number of schemes. The upward trajectory requires 3D planning, regulation and licensing to manage sustainable deployment. We review geological factors controlling thermal and flow processes in the anthropogenically-altered subsurface, critical for resource management with multiple users of the same space. Potential interactions of mine water geothermal schemes with the wider environment are also summarized, leading towards concepts of 3D mine water thermal blocks, protection zones, or management strategies integrating heating, cooling and storage demands. Factors such as the magnitude, extent and timescale of thermal processes to underpin management approaches are poorly quantified by data measured at-scale under varying pumping rates and thermal loads. We demonstrate early insights of how two infrastructures, the UK Geoenergy Observatory in Glasgow and the Coal Authority's Mine Water Heat Living Lab in Gateshead, can measure and monitor heat-flow processes in real world settings to provide an evidence base. For example, a thermal storage test at Glasgow showed rapid temperature changes in the rock and mine workings at the re-injection borehole and indicated an influence of lithologically-controlled transmissivity and thermal conductivity on temperature dissipation and recovery.

<p>Aquifer Thermal Energy Storage (ATES) systems use reversible abstraction and injection in combination with warm and cold wells to provide efficient heating and cooling solutions at scales up to ~0.5 MW per installation. It has been shown that these systems are able to improve the efficiency of thermal installations, but rely on an appropriate design, especially when several ATES systems share the same aquifer. In this work, we combine groundwater flow and heat transport numerical models with optimization frameworks to investigate the optimal distribution of wells for avoiding system interferences and improving recovery efficiency. To that end, we employ hypothetical modelling scenarios based on geological properties of the Sherwood Sandstone bedrock aquifer as one of the main potential targets for the development of ATES systems in the UK. Some of the available information is acquired from activities at the UK Geoenergy Observatory (UKGEOS) in Cheshire, which is under construction and will be equipped with a range of technologies and monitoring sensors for research, training, and on-site experiments. The Observatory will be open to industry and the research community to evaluate technological options for shallow geothermal use and energy storage and to gain a detailed hydraulic and thermal characterization of the Sherwood Sandstone. As practical application, we present an approach for the optimal design of the installation of multiple doublets that consider various spatial features as decision variables. The benchmark solution is provided by a simulation-optimization framework that uses a direct coupling of the groundwater flow and heat transport numerical model with an evolutionary algorithm. This approach is typically hampered by increased computational cost due to the time-intensive numerical simulations and the thousands of objective function evaluations required until convergence of the evolutionary algorithm is achieved. Therefore, we also investigate a lower computational resource strategy by applying surrogate-assisted optimization methods which are either embedded in the operations of the evolutionary algorithm or utilize an adaptive-recursive framework. The performance of the surrogate-based optimization method is assessed via several independent optimization trials and for different computational budgets. The ability of the surrogate-based optimization frameworks to approximate a near global solution is compared against the benchmark solution.</p>

Mine water geothermal has great potential to provide low carbon heating, cooling and energy storage. Some successful examples have shown that a flooded mine is a reliable, low carbon heat source and could contribute to a new green energy future for many European post-mining regions. To date, however, this potential has been hindered by scientific and technical challenges that have resulted in delay, cost overrun, or even abandonment of some mine water geothermal projects. Key sources of uncertainty that present challenges for developers, operators and regulators are groundwater flow behaviour and temperature distribution in abandoned mines under abstraction/reinjection cycles, the long-term sustainability of the geothermal system, and its interactions and impacts in the surrounding environment. The UK Geoenergy Observatory (UKGEOS) in Glasgow, Scotland, is an at-scale research facility with exceptional levels of hydrogeological and thermal characterisation and downhole instrumentation designed to monitor and quantify subsurface change and provide data to address challenges and risks associated with mine water geothermal systems design and operation. The Observatory includes four mine water boreholes connected in an open loop configuration with pumps for abstraction/reinjection, a heat pump-chiller and three different heat exchangers to enable testing of multiple modes of heat pump operation (heating and cooling) and component performance. A further two boreholes intercepting mine workings are equipped with downhole electrical resistivity tomography (ERT) and hybrid fibre-optic cables for distributed temperature sensing (Passive and Active DTS). Together with five environmental monitoring boreholes, a seismic monitoring borehole and ten hydrogeological downhole data loggers for continuous pressure, temperature, and electrical conductivity monitoring, the dedicated Observatory, which is not connected to any customers, is well equipped to examine the interaction and impacts of geothermal energy systems.In this work we present a comprehensive set of initial hydrogeological and thermal observations collected during the construction and commissioning stages of the Observatory, including long term baseline monitoring, results of initial well pumping and heat abstraction/reinjection tests. These observations include evidence for the general groundwater flow circulation in the system, groundwater level response to recharge events, different transmissivities in different mined zones, and limited connectivity between mine workings at different depths, the surrounding aquifers and the River Clyde. We have integrated hydrogeological, thermal, and other information to develop an initial conceptual hydrogeological model of the system. Using the conceptual model and field data we have developed flow and heat numerical models to evaluate alternative scenarios of heating and cooling. Modelling results indicate variable flow paths and response times for thermal breakthrough for different geothermal operational configurations. Academic and commercial researchers are encouraged to get in touch to discuss using the Observatory’s unique capability for future mine water geothermal energy investigations, including investigating the behaviour, sustainability and impacts of groundwater flow and temperature under geothermal abstraction/reinjection cycles.

Abstract Understanding the subsurface is crucial in building a sustainable future, particularly for urban centers. Importantly, the thermal effects that anthropogenic infrastructure, such as buildings, tunnels, and ground heat exchangers, can have on this shared resource need to be well understood to avoid issues, such as overheating the ground, and to identify opportunities, such as extracting and utilizing excess heat. However, obtaining data for the subsurface can be costly, typically requiring the drilling of boreholes. Bayesian statistical methodologies can be used towards overcoming this, by inferring information about the ground by combining field data and numerical modeling, while quantifying associated uncertainties. This work utilizes data obtained in the city of Cardiff, UK, to evaluate the applicability of a Bayesian calibration (using GP surrogates) approach to measured data and associated challenges (previously not tested) and to obtain insights on the subsurface of the area. The importance of the data set size is analyzed, showing that more data are required in realistic (field data), compared to controlled conditions (numerically-generated data), highlighting the importance of identifying data points that contain the most information. Heterogeneity of the ground (i.e., input parameters), which can be particularly prominent in large-scale subsurface domains, is also investigated, showing that the calibration methodology can still yield reasonably accurate results under heterogeneous conditions. Finally, the impact of considering uncertainty in subsurface properties is demonstrated in an existing shallow geothermal system in the area, showing a higher than utilized ground capacity, and the potential for a larger scale system given sufficient demand.

Summary The thermal properties of rocks and soils are of great importance to the design of renewable energy systems including geothermal wells and underground energy storage systems. However, the UK has variable geology/lithologies and poor availability of published thermal properties data linked to Group, Formation, or litho-facies creates uncertainty. The testing of 59 samples of Sherwood Sandstone Group sandstone (Liverpool, NW England) found the average intrinsic thermal conductivity (λh sat) is 3.2 W/mK, thermal diffusivity of 0.14 m2/day and estimated volumetric heat capacity 2.0 MJ/m3/K. From a technical feasibility perspective, the Sherwood Sandstone aquifer is a very good candidate for large-scale Open loop GSHP, free-cooling, and Aquifer Thermal Energy Storage (ATES) technology deployment. The measured average partially-saturated horizontal thermal conductivity of Mercia Mudstone Group argillaceous/mudstone facies (Newport, S Wales) is 1.9 W/mK, diffusivity is 0.09 m2/day, and estimated volumetric heat capacity of 1.9 MJ/m3/K, based on 29 samples. The MMG is a good candidate for Closed-loop GSHP and Borehole Thermal Energy Storage, but low permeability and yield, and soluble mineral content (gypsum) makes it a poor candidate for ATES. Where the MMG overlies the SSG it provides natural thermal insulation which will reduce ground-side heat losses and enhance whole-system efficiency.

The METEOR project (Modelling Exposure Through Earth Observation Routines) is a three year project ending in March 2021, co-funded by the UK Space Agency International Partnership Programme. The aim of this project was to develop innovative methods to understand multi-hazard and exposure, and to deliver robust data for Disaster Risk Management (DRM) in Nepal and Tanzania. In developing economies there is a pressing need to characterise hazard, exposure and vulnerability to allow for comprehensive DRM plans and pre-positioning. In the METEOR project these exposure protocols and standards were co-developed and validated in Nepal and Tanzania to ensure that they are fit-for-purpose. Many multi-hazard mapping approaches focus on the frequency of events and use historical financial losses as a proxy for infrastructure impact or exposure (Bell and Glade, 2004; Tate et al., 2010; Schmidt et al., 2011; Kappes et al., 2012). Whilst such approaches may be appropriate for hazards with historic inventories detailing the distribution and scale of events, for others estimation of key factors such as historic frequency, or probability of occurrence or losses, is much more complex. Here we will present a new methodology for assessing the national impact of multi-hazards on exposure, grounded in earth observation data, in the context of data paucity and high levels of inherent uncertainty. We explore a subset of the METEOR data for Nepal to discuss the main controls on the uncertainty of the final outputs of our model. We also show how our model can be tied to existing vulnerability curves to link hazard assessments with expected damage.

Mine water geothermal heat production and storage can provide a decarbonised source of energy for space heating and cooling, however the large resource potential has yet to be exploited widely. Besides economic, regulatory and licensing barriers, geoscientific uncertainties such as detailed understanding of thermal and hydrogeological subsurface processes, resource sustainability and potential environmental impacts remain. The UK Geoenergy Observatory in Glasgow is a research infrastructure for investigating shallow, low-temperature coal mine water heat energy resources available in abandoned and flooded mine workings at depths of around 50-90 m. It is an at-scale ‘underground laboratory’ of 12 boreholes, surface monitoring equipment and open data. The Glasgow Observatory is accepting requests for researchers and innovators to undertake their own experiments, test sensors and methods to increase the scientific evidence base and reduce uncertainty for this shallow geothermal technology.

The shallow subsurface comprising groundwater bodies as well as solid rock formations in the uppermost tens to hundreds of meters below surface offer significant resources for renewable heating, cooling and seasonal underground heat storage. Shallow geothermal energy (SGE) comprises the technologies to exchange heat between the subsurface and surface via closed loop or open loop heat exchangers. Although SGE just covered around 2% of the renewable heat production in the EU in 2018, its huge potential for low temperature heating and cooling supply is expected to lead to a significant market growth across Europe in the upcoming decade. Especially as SGE offers the unique possibility to supply heating, cooling and storing waste heat with one technology. SGE offers advantages especially in urban areas. It does not produce waste heat if applied for cooling, which can be considered as an important measure to mitigate urban heat islands. It consumes low amount of surface space for its installation and applying SGE is free of emissions in terms of aerosols or noise. Moreover, it can be combined with other renewables such as solar and waste heat or excess energy. In these cases, SGE acts as a seasonal heat storage. The increasing interest in SGE in urban areas, however, puts pressure on the subsurface, especially on shallow groundwater bodies. In that context, SGE systems may compete with each other as well as with water supply and subsurface installations. In many European countries, management approaches of SGE are either lacking or follow the first come first serve approach. Integrative management approaches follow an information and decision cycle, starting and ending at collecting, processing and providing geoscientific data on subsurface conditions to stakeholders, such as authorities, investors and city planners. GeoERA MUSE addresses integrative management approaches for the use of SGE by harmonizing concepts and testing them in 14 European cities facing different climatic, hydrogeologic and socio-economic boundary conditions. MUSE deals with mapping resources and limitations of SGE resources and displays them in modern web-based interfaces. Knowing resources and limitations referring to interference with other SGE systems or other shallow subsurface installations is the starting point for integrative management approaches, which include summation effects and abandon first come first serve. MUSE pilot areas follow the whole management cycle from creating subsurface data (e.g. subsurface temperatures, thermal rock properties), deriving resource models (amount of energy available for use), limitations of use (contaminated areas, problematic chemical composition of groundwater) and displaying the information gained at the EGDI web platform of EuroGeoSurveys. Furthermore, MUSE interacts with local stakeholders to transfer geoscientific data models into managing strategies. In that sense, the pilot areas act as role model for other urban regions in Europe. Additionally, MUSE creates joint concepts and standards to strengthen the role of Geological Survey Organisations towards a key player in managing an efficient and sustainable use of urban subsurface in general and SGE in urban areas in detail. MUSE has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 731166.

Successful electrification of cities' heating and cooling demands depends on the sustainable implementation of highly efficient ground source heat pumps (GSHP). During the last decade, the use of shallow geothermal energy (SGE) resources in urban areas has experienced an unprecedented boost which nowadays is still showing a steady 9% market growth trend. However, the intensive market incorporation experienced by this technology entails different responsibilities towards the long-term technical and environmental sustainability in order to maintain this positive trend. Here we present a SGE management framework structure and a governance model agreed among 13 European Geological Surveys, providing a roadmap for the different levels of management development, adaptable to any urban scale, and independent of the hydrogeological conditions and the grade of development of SGE technology implementation. The management approach reported is based on the adaptive management concept, thus offering a working flow for the non-linear relationship between planning, implementation and control that establishes a cyclical and iterative management process. The generalized structure of the SGE management framework provided allows the effective analysis of policy to identify and plan for management problems and to select the best management objectives, strategies and measures according to the policy principles proposed here.

The shallow subsurface comprising groundwater bodies as well as solid rock formations in the uppermost tens to hundreds of meters below surface offer significant resources for renewable heating, cooling and seasonal underground heat storage. Shallow geothermal energy (SGE) comprises the technologies to exchange heat between the subsurface and surface via closed loop or open loop heat exchangers. Although SGE just covered around 2% of the renewable heat production in the EU in 2018, its huge potential for low temperature heating and cooling supply is expected to lead to a significant market growth across Europe in the upcoming decade. Especially as SGE offers the unique possibility to supply heating, cooling and storing waste heat with one technology. SGE offers advantages especially in urban areas. It does not produce waste heat if applied for cooling, which can be considered as an important measure to mitigate urban heat islands. It consumes low amount of surface space for its installation and applying SGE is free of emissions in terms of aerosols or noise. Moreover, it can be combined with other renewables such as solar and waste heat or excess energy. In these cases, SGE acts as a seasonal heat storage. The increasing interest in SGE in urban areas, however, puts pressure on the subsurface, especially on shallow groundwater bodies. In that context, SGE systems may compete with each other as well as with water supply and subsurface installations. In many European countries, management approaches of SGE are either lacking or follow the first come first serve approach. Integrative management approaches follow an information and decision cycle, starting and ending at collecting, processing and providing geoscientific data on subsurface conditions to stakeholders, such as authorities, investors and city planners. GeoERA MUSE addresses integrative management approaches for the use of SGE by harmonizing concepts and testing them in 14 European cities facing different climatic, hydrogeologic and socio-economic boundary conditions. MUSE deals with mapping resources and limitations of SGE resources and displays them in modern web-based interfaces. Knowing resources and limitations referring to interference with other SGE systems or other shallow subsurface installations is the starting point for integrative management approaches, which include summation effects and abandon first come first serve. MUSE pilot areas follow the whole management cycle from creating subsurface data (e.g. subsurface temperatures, thermal rock properties), deriving resource models (amount of energy available for use), limitations of use (contaminated areas, problematic chemical composition of groundwater) and displaying the information gained at the EGDI web platform of EuroGeoSurveys. Furthermore, MUSE interacts with local stakeholders to transfer geoscientific data models into managing strategies. In that sense, the pilot areas act as role model for other urban regions in Europe. Additionally, MUSE creates joint concepts and standards to strengthen the role of Geological Survey Organisations towards a key player in managing an efficient and sustainable use of urban subsurface in general and SGE in urban areas in detail. MUSE has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 731166.

Reaching Net Zero CO2 emissions by 2050 will require rapid and wide-scale deployment of renewable heating technologies in rural and urban areas, including open and closed loop type production wells and borehole heat exchangers, supplying individual, shared, and centralised heat pumps as part of wider district heating and cooling grids. Ground and groundwater conditions are naturally variable and are a key factor in system viability, capital cost and long-term performance. Engineering approaches for heating and cooling of buildings should be optimised for the local thermo-geological conditions to avoid system interference and thermal degradation. Sustainable use of shallow geothermal systems can be achieved by adopting an environmental stewardship approach, integrating geological information within energy master plans, taking full advantage of subsurface data visualisation technology and integrated planning and modelling tools. We present a method for creating a digital shallow geothermal opportunities map - mostly aimed at moderate- to expert-skill level geoenvironmetal and energy consultants, planners and civil engineers. The output is a digital 1:50 000 scale equivalent thematic map, that provides a synthesis of available technical information by combining data such as 3D superficial geological model data - delimiting aquifer and non-aquifer boundaries, groundwater levels and temperatures, aquifer thickness, flow direction, possibly with inset tables summarising groundwater chemistry and key physical properties of the main geological units such typical thermal conductivity. Built infrastructure that could constrain drilling locations, as well as potential water discharge points and open water heat source and storage opportunities, such as sewers, rivers, canals, docks, and lakes, might also be included in the map. Local development plans and heat demand mapping data could then be integrated with the opportunities map to identify and prioritise districts that would benefit from more detailed viability studies for conversion of fossil fuel heating systems to low carbon heating and cooling technologies. This project has received funding from the European Union’s H2020 research and innovation programme under the GeoERA MUSE project – Managing Urban Shallow Geothermal Energy.