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ERE2.3

EDI
Geothermal resources in the framework of climate change and sustainability

Geothermal energy is often viewed as a source of green, ideally renewable, energy. The sustainability of geothermal exploitation, however, has many aspects and needs to be looked at in more detail. Geothermal’s sustainability applies to three distinct topics.
On the one hand, the sustainability of reservoir exploitation plays an important role if operators plan on using geothermal waters of a specific aquifer over a long period without short-circuiting and without changing the hydraulic, hydrogeochemical and mechanical properties of the reservoir. On the other hand, operation strategies, quality of equipment, and hydrochemical signatures of the exploited reservoir waters impact and limit the sustainability of geothermal equipment such as pipes and pumps.
Lastly, the contribution hydrothermal energy is able to make towards an efficient energy transition in the name of climate change mitigation needs to be investigated further, especially considering its inherent low degree of efficiency, its environmental impacts at the well site and overall social acceptance.
This session aims at an interdisciplinary platform addressing the overarching aspects of geothermal exploitation and its role in environment protection. While still technical, we also invite stakeholders and policy makers to discuss whether the socio-economic and legal frameworks require adjustments to promote geothermal energy.

This session will focus on, but is not limited to:

- Impacts of stimulation, exploitation, and any water treatment on the reservoir

- Strategies for assessment and monitoring of the sustainability of geothermal reservoir exploitation (case studies and success stories)

- Impacts of chemical properties of the water on geothermal equipment (corrosion, scaling…)

- Life cycle assessments of geothermal systems

- Geothermal emissions of equipment manufacturing and operation of geothermal power plants

- Impacts on biodiversity/integrity of ecosystems in the geothermal reservoirs

- Social acceptance, community engagement, position in the current legal framework

Convener: Annette DietmaierECSECS | Co-conveners: Ingrid Stober, Tobias Björn Weisenberger
Presentations
| Thu, 26 May, 10:20–11:23 (CEST)
 
Room 0.96/97

Thu, 26 May, 10:20–11:50

Chairpersons: Annette Dietmaier, Felix Schölderle

10:20–10:27
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EGU22-2328
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ECS
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Virtual presentation
Stacia Ryder et al.

Deep geothermal energy is regarded as an important renewable source of power and heat that has the potential to occupy a central place in a just energy transition as part of the UK’s strategy to meet its Net Zero Commitment.  Access to deep geothermal energy bears some similar risks to shale gas development, a practice met in the UK with much public concern and controversy. Existing research on shale gas has established that risk perceptions, notably around induced seismicity, were of particular importance to the public and in local communities where exploration was proposed. Furthermore, the UK government’s approach to regulating induced seismicity across these two industries has not been uniform. It thus remains unclear how the exploitation of geothermal energy will be received more broadly, and how the government might regulate geothermal activity . 

The exploration and exploitation of geothermal energy is intrinsically technical, yet geothermal developments also include social, spatial and political aspects that have so far been neglected in geothermal energy research. As such, in this paper we draw on multiple data sets, including interviews with government, industry and public stakeholders to compare and contrast governance approaches and public risk perceptions tied to shale gas and geothermal energy production in the UK. We suggest some key differences between the shale and geothermal energy industries in terms of technologies, social acceptance and implications for climate change. Yet we also point to divergent issues, in terms of a lack of a cohesive regulatory framework or guidance for community engagement tied to geothermal energy, and how this might negatively impact public perceptions of the practice, thwarting social acceptance. In closing, we make recommendations for establishing more systematic geothermal regulations and policies aimed at creating consistent, environmentally sustainable and socially just practices in the industry moving forward. 

How to cite: Ryder, S., Rohse, M., and Abesser, C.: Risk perception, regulation, community engagement and acceptance: Navigating the legal and social UK geothermal landscape , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2328, https://doi.org/10.5194/egusphere-egu22-2328, 2022.

10:27–10:34
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EGU22-4288
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ECS
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On-site presentation
Michael MacKenzie et al.

Minewater heating is a form of shallow geothermal energy provision that exploits abandoned subsurface mines that have since flooded after mining activity ceased. Groundwater that occupies the void space left from material extraction is warmed to ambient temperatures by heat transfer exchanges with the surrounding rock.

By using ground source heat pumps, the temperatures of these waters can be lifted to those suitable for domestic heat use, with efficient electrical input.  

An assessment to determine the feasibility of the implementation of a minewater heating system on the Durham University campus is currently in progress, with results due in March 2022. The system would use abandoned coal mines of the Durham Coalfield to heat several student accommodation buildings built above.

Assuming abstraction and reinjection of the minewater, we investigated the available heat resource using a numerical modelling tool developed at Durham University. This tool modelled the minewater flow through the void space of the mines and thermal interaction with the surrounding rock.

A new methodology was developed for the digitisation of historic mine plans provided by the UK’s Coal Authority, which have then been modelled to provide 3D visualisation of technical factors critical to the success of such a project. Various configurations have been tested, and results indicate over 11 million kWh of heat in place resource available, at temperatures of 14°C. This heat in place figure is likely an underestimation of the resource as records indicate deeper seams were also mined at the locality.

 

We subsequently carried out an assessment of the economic feasibility. If a decentralised configuration were chosen for the design, it would be advisable to focus on three buildings with the most student rooms. Initial costs would be high, driven mainly by the associated costs of drilling injection and extraction wells. As the target seams are relatively shallow (145m for extraction and 70m for injection), smaller wells could be used, costing roughly £40,000 per well. If a centralised design were used, costs would be reduced by drilling fewer wells. However, retrofit work to replace the original centralised gas infrastructure connections could induce significant cost and disruption. However, running costs would be low, and emissions savings from not using gas boilers would be significant; peak daily CO₂ emissions from gas were 17,992 kg in 2019.

Finally, to assess the internal policy structure of the university and the feasibility of permission to be granted for the project, a social acceptance study was undertaken with key members of the university’s Board of Directors. Considering the project through the concept of risk, obstacles to implementation were identified, and potential policy solutions were developed.

This study provided insights into current institutional views on engaging with innovative energy technologies. Future work may benefit from understanding these to produce relevant solutions to mitigate them in their feasibility studies.

How to cite: MacKenzie, M., van Hunen, J., and Gluyas, J.: A feasibility assessment of the implementation of a minewater heating system on the Durham University estate., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4288, https://doi.org/10.5194/egusphere-egu22-4288, 2022.

10:34–10:41
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EGU22-13573
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Virtual presentation
Balazs Bodo et al.

CROWDTHERMAL is a project funded under the European Union’s Research and Innovation programme Horizon 2020 – Grant Agreement n°857830. It is a is a 36-month project led by the European Federation of Geologists (EFG), with a consortium of 10 partners from 7 different European countries.

The main purpose of CROWDTHERMAL is to support the uptake of geothermal energy projects in Europe. To reach this goal it is necessary to involve and empower the public in the development of such projects, and CROWDTHERMAL has developed social engagement strategies that were validated in three different case studies over the project’s implementation: Hungary, Spain, and Iceland.

In addition to the social aspects, the project produced numerous reports on alternative financing schemes, such as crowdfunding, and risk mitigation tools to be implemented in the development of a geothermal project. These tools aim to increase financial security and attract investments in geothermal energy in Europe – contributing to the EU Green Deal goals for 2050.

In 2022, the final year of CROWDTHERMAL, the consortium is focused on the development, improvement, and deployment of a set of Core Services. The Core Services are a result of reports, analysis and studies developed and validated along the project that are addressed to different target audiences: the community of citizens, geothermal project developers, and local authorities. These outputs are the following: 1) Assistance on the development of an economic model of a geothermal project; 2) Step plan regarding finance and risk mitigation tools to be considered; 3) Meta-database of current geothermal projects in Europe; 4) Self-learning materials on geothermal energy, alternative finance, social aspects, and risk mitigation; and 5) An online decision tree algorithm: a workflow with a sequence of questions that follow a logical order, with the purpose of selecting which strategies are the most appropriate for a specific phase of a geothermal project related to social, environmental, resource risk and financial factors.

These CROWDTHERMAL Core Services are designed to continue beyond the EC-funded period. From these pre-defined outputs of the project, the partners will further elaborate the exploitation strategy and transform some of them into added value services that will be commercialized, with an embedded consultancy from experts in CROWDTHERMAL consortium. For example, communities can be guided on how to transform community initiatives into geothermal projects through co-financing; geothermal project developers will learn more about mechanisms for social acceptance and engagement, as well as economic modelling of a geothermal project; and public authorities will be able to bridge private initiatives and the community – fostering the uptake of geothermal energy in Europe.

How to cite: Bodo, B., Fernández Fuentes, I., Tameirão Pinto, M., Kleverlaan, R., Friederichs, G., and Baisch, C.: CROWDTHERMAL - developing financial and social engagement strategies for geothermal projects, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-13573, https://doi.org/10.5194/egusphere-egu22-13573, 2022.

10:41–10:48
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EGU22-5957
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ECS
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On-site presentation
Robin Perruchoud et al.

Green hydrogen produced through electrolysis using renewable energy has the potential to decarbonize many sectors by replacing fossil fuels. Although production is currently marginal, green hydrogen projects are initiated and assessed all around the globe, ranging from small energy systems to large-scale production units. Previous studies have identified a wide range of key stakeholders that influence the diffusion of green hydrogen technologies. However, an understanding of the overall complexity of the emerging hydrogen sector regarding techno-economic, social, and environmental aspects is needed. The main objective of this study is to provide a depiction of an emerging sustainable technology sector by integrating various stakeholders’ perspectives. Based on this mapping key mechanisms that foster or hinder the production of green hydrogen will be identified. To perform our study, we chose a green hydrogen production project at the Hellisheiði geothermal power plant (Iceland) to construct a causal loop diagram (CLD) of the Icelandic green hydrogen production sector. Seven semi-structured interviews and one e-mail interview were conducted with relevant stakeholders. The National Innovation System was taken as a conceptual model in order to encourage the participants to answer in a systemic manner. Variables and causal links were then extracted from the interview transcripts using a coding process adapted from the literature. An overall CLD was constructed, showing the dynamic complexity of the system. The results show that mobility and export are the main sources for enhanced demand. Since most power companies in Iceland are state owned, green hydrogen supply comes mainly from energy companies, and strongly depends on political support. The importance of civil society, especially concerning the topics of nature protection and climate awareness, is also depicted. Additionally, a range of social, technical, and economical factors are identified, as well as their impact on the system’s behavior. The diagram allows for comprehension of stakeholders’ expectations and concerns with their potential consequences on the diffusion on green hydrogen technologies. The use of system dynamics and causal loop modelling provides a comprehensive view on the problem and helps to address issues that could be overlooked without it. Some of these causal chains could potentially lead to policy failure if not addressed early enough. The findings can be used to enhance cooperation between stakeholders and guide decision-making processes.

How to cite: Perruchoud, R., Vögeli, G., and Finger, D. C.: Opportunities and drivers for green hydrogen production from renewable energy: Constructing of a causal loop diagram from stakeholders perspective in Iceland., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5957, https://doi.org/10.5194/egusphere-egu22-5957, 2022.

10:48–10:55
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EGU22-4279
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On-site presentation
Thomas Baumann

Geothermal ressources for heat and power generation are an integral part of the transition from fossil fuels to clean and sustainable energy and have been successfully developed in the North Alpine Foreland Basin since the 2000s. The timeframe since the first exploration activities is rather short and data on induced changes in the aquifer is scarce. It might be a good idea to take a look at the development classical groundwater ressources for comparison, even more so, if the geothermal facility also includes a net withdrawal for eg. medical or wellness applications.
Most deep groundwater aquifers are of vital importance but strongly limited as ressources for drinking water. Depletion of these aquifers is easy to assess and usually handled well in the legislative procedure. The development of the hydrochemical state and the possible occurrence of mobile persistent trace pollutants, on the other hand, is hard to predict. Here, the current assessment framework which is based on the protection of the aquifer by impermeable layers falls short: together with groundwater renewal the age structure of the aquifer has to change. Old groundwater is replaced by more recent groundwater. Substances with a similar transport behaviour as wateritself will sooner or later show up in these deep groundwater ressources. Examples from bottled water producers show that the development from a state without any traces of anthropogenic substances to a the first occurrence is sharp and irreversible.
Future development concepts for deep groundwater aquifers have to take the age structure of the aquifer into account when defining acceptable withdrawal rates, groundwater protection zones and technical operations which influence the integrity of the protecting layers.
We present a conceptual assessment and monitoring concept for deep groundwater aquifers which includes the risks posed by unconventional uses of the impermeable layers (foundations, corroded wells, geothermal, ...).

How to cite: Baumann, T.: Assessment of the hydrochemical integrity of deep geothermal aquifers - Lessons from bottled water producers, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4279, https://doi.org/10.5194/egusphere-egu22-4279, 2022.

10:55–11:02
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EGU22-6292
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Virtual presentation
Petar Gvero et al.

The geothermal energy potential in the Balkan area includes locations in Slovenia, Hungary, Romania, Bulgaria, Serbia and Bosnia and Herzegovina. Although the potential for clean, cost-efficient, and renewable geothermal heating energy is well known, exploitation of geothermal sources is still hampering. According to the existing surveys, mappings, and calculations, Banja Luka area is built on a geothermal underground reservoir, which is currently only used for balneology purposes. Due to the specific geographic position and the emissions from the existing district heating system based on biomass and heavy petrol, the air quality in Banja Luka is severely mitigated during the winter season. In order to assess the potential and the challenges of geothermal district heating for Banja Luka numerical energy modeling, life cycle analysis of the energy systems, and stakeholder assessment are currently being performed. These activities are currently carried out in the frame of international cooperation between the University of Banja Luka, Reykjavik University in Iceland, and the Energy Institute at the Johannes Kepler University in Linz, Austria. Our preliminary results indicate that geothermal district heating in Banja Luka can provide a reliable, cost-efficient, clean, renewable, and domestic heat supply to the residents of Banja Luka. Furthermore, our initial findings indicate that that the main challenges in developing geothermal district heating in Banja Luka are complex bureaucratic processes, high skepticism among the decision-makers, and a high degree of conflicting interests among relevant stakeholders. This presentation will conclude by highlighting how geothermal district heating in Banja Luka falls in line with the concepts of the new EU Green Deal and the obligations of Bosnia and Herzegovina according to Energy Community Treaty.

How to cite: Gvero, P., Jón Ásbjörnsson, E., Finger, D., Kotur, M., Musonye, X., Kardas, D., and Pupcevic, M.: The potential of geothermal district heating in the city of Banja Luka, Bosnia and Herzegovina, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6292, https://doi.org/10.5194/egusphere-egu22-6292, 2022.

11:02–11:09
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EGU22-10599
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ECS
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Virtual presentation
Emma Daira Baizabal Gómez et al.

Geothermal high enthalpy resources can be an important potential source to satisfy Mexico’s energy requirements ; nevertheless, low and moderate enthalpy resources may contribute through the direct uses to replace fossil fuels. In both cases, the exploitation of geothermal resources are an important factor inthe energy transition that the whole world strives to achieve. Furthermore, it has an important social impact in the communities, where the use of geothermal energy can bring considerable benefit. In this work, a geothermal characterization with a geographic approach is presented for the “Atotonilco” (hot water in native language) town in Calcahualco municipality of Veracruz state (eastern México). The surface manifestations in the area are calcium-carbonate warm springs with flows from 1 to 12 liters per second. The temperature at depth was estimated between 70°C and 74°C with the calcedony geothermometer, which corresponds to a low enthalpy resource. A preliminary conceptual model of the Atotonilco geothermal area, using all data and a list of the feasible direct uses applications are proposed. These proposals consider the social and economic characteristics of the study area that were observed during the field work. The recommended actions include dissemination of the results of this research, as an important contribution to the development of geothermal resources in Atotonilco town.

Keywords: Geothermal energy, environmental geography, renewable energy, direct use, geochemical exploration, geoscience dissemination.

Acknowledgment

Thanks to Dr. Ramón Espinasa Pereña for his technical support during the field work. Thanks to the Laboratory of Analytical Chemistry of the Institute of Geophysics, UNAM, especially to the QFB Olivia Cruz, M in Ing. Alejandra Aguayo and QFB Omar Neri, for carrying out the chemical analyzes of water presented here.

How to cite: Baizabal Gómez, E. D., Jácome Paz, M. P., Pérez Zarate, D., de la Fuente Rivera, J. R., and Prol Ledesma, R. M.: Characterization of Atotonilco geothermal area, Veracruz, Mexico, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10599, https://doi.org/10.5194/egusphere-egu22-10599, 2022.

11:09–11:16
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EGU22-8639
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ECS
Mar Alonso et al.

Active or recent volcanism indicates the presence of high-enthalpy resources at depth. This is obvious when visible surface emanations as volcanic plumes, fumaroles, solfataras or bubblings appear. However, visible manifestations of deep anomalies do not always appear at the surface, making more difficult the detection of possible geothermal reservoirs. In this work, we propose that in areas where there are no visible emanations, it is possible to make an estimation of the associated thermal energy of the reservoir. For this purpose, 15 volcanic systems located in different geotectonic environments have been studied, where diffuse 3He and 4He emission and thermal energy released have been calculated. This work has focused on the study of diffuse He emissions due to its chemically conservative properties as a noble gas, helium is an excellent indicator of magmatic activity allowing to delimit permeable areas of preferential ascent of deep origin fluids. Two different methodologies for the calculation of diffuse 3He and 4He emissions have been proposed. In addition, the thermal energy released has been calculated following the methodology proposed by Chiodini et al., 2001. A consistent observation across the entire study is that those areas with relatively high diffuse 3He and 4He emissions also show relatively high thermal energy released values, suggesting a clear and positive relationship between the parameters. This implies that, in volcanic areas where no visible geothermal emanations are observed, and therefore, the inability to sample, but anomalies in the diffuse 4He emission are present, there should be a deep thermal anomaly associated, and therefore, a possible geothermal reservoir.

 

  • Chiodini, F. Frondini, C. Cardellini, D. Granieri, L. Marini, G. Ventura. CO2 degassing and energy release at Solfatara volcano, Campi Flegrei, Italy. J. Geophys. Res. 106 (B8) (2001) 16213e16221, https://doi.org/10.1029/2001JB000246.

How to cite: Alonso, M., Pérez, N. M., Hernández, P. A., Padrón, E., Melián, G., Rodríguez, F., Padilla, G., Barrancos, J., Asensio-Ramos, M., Fridriksson, T., and Sumino, H.: Diffuse emission of 3He and 4He and thermal energy released in volcanic systems, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8639, https://doi.org/10.5194/egusphere-egu22-8639, 2022.

11:16–11:23
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EGU22-11801
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ECS
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On-site presentation
Nele Hastreiter and Thomas Vienken

Increasing the share of renewables in the heating sector is crucial to reduce CO2-emissions. Using the shallow geological subsurface for heating and cooling is part of the solution. Especially the use of shallow geothermal energy for heating is widely applicable. An intensive but at the same time sustainable shallow geothermal use is essential to avoid interactions between geothermal users with a resulting decrease in system efficiency or competing use with other subsurface usages, e.g. groundwater provision. The intensive thermal use of the shallow subsurface is generally controlled by monitoring of subsurface or groundwater temperatures. Induced changes of subsurface or groundwater temperatures are required to not exceed specific thresholds over time. However, the urban subsurface is exposed to different sources of temperature impacts which need to be considered during the long term subsurface or groundwater temperature monitoring to determine absolute changes. This is especially true for new urban quarters. Elevated groundwater temperatures in densely populated areas in comparison to the rural surroundings, often referred to as groundwater urban heat islands, have been observed and investigated over decades. However, only little information is available about the formation of heat islands over time and yet, its effects are hardly considered in groundwater temperature monitoring practice. To overcome this lack of knowledge, this study follows an innovative approach by coupling simulated elevated groundwater temperatures for a densely settled quarter with empiric groundwater temperature data. Therefore, heat losses from buildings and their contribution to the formation of groundwater urban heat islands over time are analysed for a refurbished quarter with a building stock of 150 houses and intensive use of shallow geothermal energy in Cologne, Germany.  To simulate heat losses from buildings, different scenario analyses with houses of varying insulation standards are performed using a building physics software. Obtained results were then implemented into a groundwater flow model to evaluate the impact on underground temperatures over time and compared with measured data of the same area. Simulation results reveal that the geothermal heating activities impact the groundwater temperatures more than the monitoring data suggests.

How to cite: Hastreiter, N. and Vienken, T.: An innovative temperature monitoring approach to ensure the sustainable use of shallow geothermal energy on quarter scale, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11801, https://doi.org/10.5194/egusphere-egu22-11801, 2022.