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Alejandro García Gil
Geological Survey of Spain (IGME), C/ Ríos Rosas 23, 28003 Madrid, Spain

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Journal article
Published: 24 February 2021 in Renewable Energy
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The Canary Island archipelago holds 2.2 million inhabitants and received more than 14 million tourist visitors in 2019. Its volcanic origin and the presence of recent volcanic activity highlight its potential geothermal interest for heat production, therefore offering an attractive pathway for a renewable energy supply, not only for power generation and deep geothermal exploitation but also for low-enthalpy heating and cooling production. This work investigates nine touristic infrastructures in the Canary Islands which experienced a transition from conventional heat production systems to shallow geothermal energy (SGE) systems. The SGE systems established consisted in ultra-low temperature district heating and cooling (DHC) micro-networks involving, in most cases, small apartment blocks fed by shallow geothermal plants with an average cooling capacity of 602 kW and a heating capacity of 614 kW. The examination of this transition has exhibited an average saving of 374 MWh, 69,235 € and 280 tCO2 for each installation every year. This work provides evidence of the economical, energetical and environmental advantages of SGE technology in volcanic islands facing both and enormous heating and cooling demand due to tourism, in an energy-dependent system that also faces the challenge of the decarbonization of the heating production sector.

ACS Style

Juan C. Santamarta; Alejandro García-Gil; María Del Cristo Expósito; Elías Casañas; Noelia Cruz-Pérez; Jesica Rodríguez-Martín; Miguel Mejías-Moreno; Gregor Götzl; Vasiliki Gemeni. The clean energy transition of heating and cooling in touristic infrastructures using shallow geothermal energy in the Canary Islands. Renewable Energy 2021, 171, 505 -515.

AMA Style

Juan C. Santamarta, Alejandro García-Gil, María Del Cristo Expósito, Elías Casañas, Noelia Cruz-Pérez, Jesica Rodríguez-Martín, Miguel Mejías-Moreno, Gregor Götzl, Vasiliki Gemeni. The clean energy transition of heating and cooling in touristic infrastructures using shallow geothermal energy in the Canary Islands. Renewable Energy. 2021; 171 ():505-515.

Chicago/Turabian Style

Juan C. Santamarta; Alejandro García-Gil; María Del Cristo Expósito; Elías Casañas; Noelia Cruz-Pérez; Jesica Rodríguez-Martín; Miguel Mejías-Moreno; Gregor Götzl; Vasiliki Gemeni. 2021. "The clean energy transition of heating and cooling in touristic infrastructures using shallow geothermal energy in the Canary Islands." Renewable Energy 171, no. : 505-515.

Case study
Published: 14 February 2021 in Groundwater
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Global demands for energy efficient heating and cooling systems coupled with rising commitments toward net zero emissions is resulting in wide deployment of shallow geothermal systems, typically installed to a depth of 100 to 200m, and in the continued growth of the global ground source heat pump (GSHP) market. Ground coupled heat pump (GCHP) systems take up to 85% of the global GSHP market. With increasing deployment of GCHP systems in urban areas coping with limited regulations, there is growing potential and risk for these systems to impact the subsurface thermal regime and to interact with each other or with nearby heat‐sensitive subsurface infrastructures. In this paper, we present three numerical modelling case studies, from the UK and Canada, which examine GCHP systems’ response to perturbation of the wider hydrogeological and thermal regimes. The studies demonstrate how GCHP systems can be impacted by external influences and perturbations arising from subsurface activities that change the thermal and hydraulic regimes in the area surrounding these systems. Additional subsurface heat loads near existing schemes are found to have varied impacts on system efficiency with reduction ranging from <1 % to 8 %, while changes in groundwater flow rates (due to a nearby groundwater abstraction) reduced the effective thermal conductivity at the study site by 13%. The findings support the argument in favour of regulation of GCHP systems or, to a minimum, their registration with records of locations and approximate heat pump capacity – even though these systems do not abstract / inject groundwater. This article is protected by copyright. All rights reserved.

ACS Style

Corinna Abesser; Robert A. Schincariol; Jasmin Raymond; Alejandro García‐Gil; Ronan Drysdale; Alex Piatek; Nicolò Giordano; Nehed Jaziri; John Molson. Case Studies of Geothermal System Response to Perturbations in Groundwater Flow and Thermal Regimes. Groundwater 2021, 1 .

AMA Style

Corinna Abesser, Robert A. Schincariol, Jasmin Raymond, Alejandro García‐Gil, Ronan Drysdale, Alex Piatek, Nicolò Giordano, Nehed Jaziri, John Molson. Case Studies of Geothermal System Response to Perturbations in Groundwater Flow and Thermal Regimes. Groundwater. 2021; ():1.

Chicago/Turabian Style

Corinna Abesser; Robert A. Schincariol; Jasmin Raymond; Alejandro García‐Gil; Ronan Drysdale; Alex Piatek; Nicolò Giordano; Nehed Jaziri; John Molson. 2021. "Case Studies of Geothermal System Response to Perturbations in Groundwater Flow and Thermal Regimes." Groundwater , no. : 1.

Journal article
Published: 24 June 2020 in Sustainability
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The long-term sustainability of shallow geothermal systems in dense urbanized areas can be potentially compromised by the existence of thermal interfaces. Thermal interferences between systems have to be avoided to prevent the loss of system performance. Nevertheless, in this work we provide evidence of a positive feedback from thermal interferences in certain controlled situations. Two real groundwater heat pump systems were investigated using real exploitation data sets to estimate the thermal energy demand bias and, by extrapolation, to assess the nature of thermal interferences between the systems. To do that, thermal interferences were modelled by means of a calibrated and validated 3D city-scale numerical model reproducing groundwater flow and heat transport. Results obtained showed a 39% (522 MWh·yr-1) energy imbalance towards cooling for one of the systems, which generated a hot thermal plume towards the downgradient and second system investigated. The nested system in the hot thermal plume only used groundwater for heating, thus establishing a positive symbiotic relationship between them. Considering the energy balance of both systems together, a reduced 9% imbalance was found, hence ensuring the long-term sustainability and renewability of the shallow geothermal resource exploited. The nested geothermal systems described illustrate the possibilities of a new management strategy in shallow geothermal energy governance.

ACS Style

Alejandro García-Gil; Miguel Mejías Moreno; Eduardo Garrido Schneider; Miguel Ángel Marazuela; Corinna Abesser; Jesús Mateo Lázaro; José Ángel Sánchez Navarro. Nested Shallow Geothermal Systems. Sustainability 2020, 12, 5152 .

AMA Style

Alejandro García-Gil, Miguel Mejías Moreno, Eduardo Garrido Schneider, Miguel Ángel Marazuela, Corinna Abesser, Jesús Mateo Lázaro, José Ángel Sánchez Navarro. Nested Shallow Geothermal Systems. Sustainability. 2020; 12 (12):5152.

Chicago/Turabian Style

Alejandro García-Gil; Miguel Mejías Moreno; Eduardo Garrido Schneider; Miguel Ángel Marazuela; Corinna Abesser; Jesús Mateo Lázaro; José Ángel Sánchez Navarro. 2020. "Nested Shallow Geothermal Systems." Sustainability 12, no. 12: 5152.

Journal article
Published: 01 April 2020 in Water
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This document develops a methodology that evaluates the impact on the environment of the rivers produced by the creation of civil infrastructures. The methodology is based on the two-dimensional hydrodynamic calculation by using shallow water equations both in the conditions prior to the creation of the infrastructure, and in the new conditions after the infrastructure is created. Subsequently, several characteristics, such as water depth and velocity, among others, are compared between the initial and final conditions, and a two-dimensional zoning of the changes observed is obtained. The methodology herein presented is useful to verify the impact that the implantation of different infrastructures around the river currents could produce. In addition, it is also relevant for carrying out a study taking into account different infrastructure options related to river currents, as well as for selecting the most suitable one. By using the methodology presented, changes on the regime of the currents caused by the infrastructures can be deduced, including a qualitative and quantitative zoning of the changes, with a special emphasis on some characteristics, such as depth and velocity. The methodology is applied in a case study for the creation of a road bridge over the Jalon River in Spain.

ACS Style

Jesús Mateo-Lázaro; Jorge Castillo-Mateo; Alejandro García-Gil; José Ángel Sánchez-Navarro; Víctor Fuertes-Rodríguez; Vanesa Edo-Romero. Comparative Hydrodynamic Analysis by Using Two−Dimensional Models and Application to a New Bridge. Water 2020, 12, 997 .

AMA Style

Jesús Mateo-Lázaro, Jorge Castillo-Mateo, Alejandro García-Gil, José Ángel Sánchez-Navarro, Víctor Fuertes-Rodríguez, Vanesa Edo-Romero. Comparative Hydrodynamic Analysis by Using Two−Dimensional Models and Application to a New Bridge. Water. 2020; 12 (4):997.

Chicago/Turabian Style

Jesús Mateo-Lázaro; Jorge Castillo-Mateo; Alejandro García-Gil; José Ángel Sánchez-Navarro; Víctor Fuertes-Rodríguez; Vanesa Edo-Romero. 2020. "Comparative Hydrodynamic Analysis by Using Two−Dimensional Models and Application to a New Bridge." Water 12, no. 4: 997.

Preprint content
Published: 23 March 2020
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Salt flats (salars) are endorheic hydrogeological systems associated with arid to hyperarid climates. The brines of salt flats account the 80 % of the world’s reserves of Li highly demanded by modern industry. About 40 % of the worldwide Li is extracted from the brine that fills the pores and cavities of the Salar de Atacama. However, the origin of the extreme Li-enrichment of these brines is still unknown.

The thick accumulation of salts and brines in salt flats results from the groundwater discharge (phreatic evaporation) near the land surface for thousands to millions of years. The strong evaporation contributes the enrichment in major cations and anions as well as other rare elements (e.g. Li, B, Ba, Sr, Br, I and F) which are very attractive for mining exploitation. However, only evaporation cannot explain by itself the extreme concentrations of some of these elements and the strong decoupling between the most evaporated brines and the most Li-enriched brines in the Salar de Atacama. Several hypotheses have been proposed to explain the extreme Li-enrichment of the salt flat brines: (a) concentrated brines leaking down from salt flats located in the Andean Plateau, (b) leaching of hypothetical ancient salt flats buried among volcanic rocks, and (c) rising of hydrothermal brines from deep reservoirs through faults. However, none of them has been able probed neither validated by a numerical model till the date.

The objective of this work is to discuss the feasibility of the different hypotheses proposed until now to explain the formation of the world's largest lithium reserve. To achieve this objective, two sets of numerical simulations of a 2D vertical cross-section of the entire Salar de Atacama basin are carried out to define (1) the origin and evolution of a salt flat and how climate cycles can affect the location of the most Li-concentrated brines by evaporation and (2) the establishment of the hydro-thermo-haline circulation of a mature salt flat basin.

ACS Style

Miguel Angel Marazuela; Carlos Ayora; Enric Vázquez Suñé; Sebastià Olivella Pastallé; Alejandro García Gil. A hydro-thermo-haline numerical approach of the groundwater flow to explain the extreme Li-enrichment in the Salar de Atacama (NE Chile). 2020, 1 .

AMA Style

Miguel Angel Marazuela, Carlos Ayora, Enric Vázquez Suñé, Sebastià Olivella Pastallé, Alejandro García Gil. A hydro-thermo-haline numerical approach of the groundwater flow to explain the extreme Li-enrichment in the Salar de Atacama (NE Chile). . 2020; ():1.

Chicago/Turabian Style

Miguel Angel Marazuela; Carlos Ayora; Enric Vázquez Suñé; Sebastià Olivella Pastallé; Alejandro García Gil. 2020. "A hydro-thermo-haline numerical approach of the groundwater flow to explain the extreme Li-enrichment in the Salar de Atacama (NE Chile)." , no. : 1.

Preprint content
Published: 23 March 2020
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Global demands for energy efficient heating and cooling systems coupled with rising commitments toward net zero emissions building infrastructure have resulted in wide deployment of shallow geothermal systems and in the continued growth in the global geothermal heat pump (GHP) market. With increasing deployment of these systems in urban areas, there is growing potential and risk for these systems to impact the subsurface thermal regime and to interact with each other or with nearby heat-sensitive subsurface infrastructures.

GHP systems have been studied in urban environments with respect to their effects on the subsurface thermal regime, and various modelling studies have investigated the sensitivity of their performance to key (hydro)geological and operational parameters. The focus of these studies has been on isolated systems, where flow conditions and background subsurface temperatures are assumed to be constant, impacted only by the modelled system itself during its operation. However, less attention has been paid to the effects on GHPs functional efficiency from perturbations in the wider hydrogeological and thermal regime, e.g. due to urbanization, multiple BHEs within tight (residential) clusters or competing subsurface uses requiring pumping of groundwater.

In this paper, we present three numerical modelling case studies, from the UK and Canada, which examine GHP systems response to perturbation of the wider hydrogeological and thermal regime. We investigate the influence of key parameters and different model realisations, e.g. relating to system design, unbalanced thermal ground loads and environmental conditions, on the modelled GHP system efficiencies and thermal interference. We highlight findings that are relevant from an economic point of view but also for regulations. Findings are discussed within the context of the contrasting design and operational pattern typical for the UK / Europe and Canada/ North America.

ACS Style

Corinna Abesser; Robert Schincariol; Jasmin Raymond; Alejandro Garcia Gil; Jonathan Busby; Ronan Drysdale; Al Piatek; Nicolo Giordano; Nehed Jaziri; John Molson. Observations from shallow geothermal modelling case studies in Canada and the UK. 2020, 1 .

AMA Style

Corinna Abesser, Robert Schincariol, Jasmin Raymond, Alejandro Garcia Gil, Jonathan Busby, Ronan Drysdale, Al Piatek, Nicolo Giordano, Nehed Jaziri, John Molson. Observations from shallow geothermal modelling case studies in Canada and the UK. . 2020; ():1.

Chicago/Turabian Style

Corinna Abesser; Robert Schincariol; Jasmin Raymond; Alejandro Garcia Gil; Jonathan Busby; Ronan Drysdale; Al Piatek; Nicolo Giordano; Nehed Jaziri; John Molson. 2020. "Observations from shallow geothermal modelling case studies in Canada and the UK." , no. : 1.

Preprint content
Published: 23 March 2020
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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.      

ACS Style

Cornelia Steiner; Stasa Borovic; Alejandro García-Gil; Claus Ditlefsen; David Boon; Ignasi Herms; Camille Maurel; Estelle Petitclerc; Mitja Janza; Mikael Erlström; Maciej Klonowski; Jan HoleČek; Sarah Blake; Vincent Vandeweijer; Radovan Cernak; Boris Maljuk. GeoERA MUSE – Managing Urban Shallow Geothermal Energy. 2020, 1 .

AMA Style

Cornelia Steiner, Stasa Borovic, Alejandro García-Gil, Claus Ditlefsen, David Boon, Ignasi Herms, Camille Maurel, Estelle Petitclerc, Mitja Janza, Mikael Erlström, Maciej Klonowski, Jan HoleČek, Sarah Blake, Vincent Vandeweijer, Radovan Cernak, Boris Maljuk. GeoERA MUSE – Managing Urban Shallow Geothermal Energy. . 2020; ():1.

Chicago/Turabian Style

Cornelia Steiner; Stasa Borovic; Alejandro García-Gil; Claus Ditlefsen; David Boon; Ignasi Herms; Camille Maurel; Estelle Petitclerc; Mitja Janza; Mikael Erlström; Maciej Klonowski; Jan HoleČek; Sarah Blake; Vincent Vandeweijer; Radovan Cernak; Boris Maljuk. 2020. "GeoERA MUSE – Managing Urban Shallow Geothermal Energy." , no. : 1.

Preprint content
Published: 23 March 2020
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Shallow geothermal systems are the most efficient and clean technology for the air-conditioning of buildings and constitutes an emergent renewable energy resource in the worldwide market. Undisturbed systems are capable of efficiently exchanging heat with the subsurface and transferring it to human infrastructures, providing the basis for the successful decarbonisation of heating and cooling demands of cities. Unmanaged intensive use of groundwater for thermal purposes as a shallow geothermal energy (SGE) resource in urban environments threatens the resources´ renewability and the systems´ performance, due to the thermal interferences created by a biased energy demand throughout the year. To ensure sustainability, scientifically-based criteria are required to prevent potential thermal interferences between geothermal systems. In this work, a management indicator (balanced sustainability index, BSI) applicable to groundwater heat pump systems is defined to assign a quantitative value of sustainability to each system, based on their intrinsic potential to produce thermal interference. The BSI indicator relies on the net heat balance transferred to the terrain throughout the year and the maximum seasonal thermal load associated. To define this indicator, 75 heating-cooling scenarios based in 23 real systems were established to cover all possible different operational conditions. The scenarios were simulated in a standard numerical model, adopted as a reference framework, and thermal impacts were evaluated. Two polynomial regression models were used for the interpolation of thermal impacts, thus allowing the direct calculation of the sustainability indicator developed as a function of heating-cooling ratios and maximum seasonal thermal loads. The BSI indicator could provide authorities and technicians with scientifically-based criteria to establish geothermal monitoring programs, which are critical to maintain the implementation rates and renewability of these systems in the cities.

ACS Style

Alejandro García-Gil; Miguel Ángel Marazuela; Miguel Mejías Moreno; Enric Vázquez-Suñè; Eduardo Garrido Schneider; José Ángel Sánchez-Navarro. The BSI indicator: preventing thermal interferences between groundwater heat pump systems. 2020, 1 .

AMA Style

Alejandro García-Gil, Miguel Ángel Marazuela, Miguel Mejías Moreno, Enric Vázquez-Suñè, Eduardo Garrido Schneider, José Ángel Sánchez-Navarro. The BSI indicator: preventing thermal interferences between groundwater heat pump systems. . 2020; ():1.

Chicago/Turabian Style

Alejandro García-Gil; Miguel Ángel Marazuela; Miguel Mejías Moreno; Enric Vázquez-Suñè; Eduardo Garrido Schneider; José Ángel Sánchez-Navarro. 2020. "The BSI indicator: preventing thermal interferences between groundwater heat pump systems." , no. : 1.

Journal article
Published: 30 January 2020 in Energy Policy
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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.

ACS Style

Alejandro García-Gil; Gregor Goetzl; Maciej R. Kłonowski; Staša Borović; David P. Boon; Corinna Abesser; Mitja Janza; Ignasi Herms; Estelle Petitclerc; Mikael Erlström; Jan Holecek; Taly Hunter; Vincent P. Vandeweijer; Radovan Cernak; Miguel Mejías Moreno; Jannis Epting. Governance of shallow geothermal energy resources. Energy Policy 2020, 138, 111283 .

AMA Style

Alejandro García-Gil, Gregor Goetzl, Maciej R. Kłonowski, Staša Borović, David P. Boon, Corinna Abesser, Mitja Janza, Ignasi Herms, Estelle Petitclerc, Mikael Erlström, Jan Holecek, Taly Hunter, Vincent P. Vandeweijer, Radovan Cernak, Miguel Mejías Moreno, Jannis Epting. Governance of shallow geothermal energy resources. Energy Policy. 2020; 138 ():111283.

Chicago/Turabian Style

Alejandro García-Gil; Gregor Goetzl; Maciej R. Kłonowski; Staša Borović; David P. Boon; Corinna Abesser; Mitja Janza; Ignasi Herms; Estelle Petitclerc; Mikael Erlström; Jan Holecek; Taly Hunter; Vincent P. Vandeweijer; Radovan Cernak; Miguel Mejías Moreno; Jannis Epting. 2020. "Governance of shallow geothermal energy resources." Energy Policy 138, no. : 111283.

Journal article
Published: 03 January 2020 in Science of The Total Environment
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Shallow geothermal systems are the most efficient and clean technology for the air-conditioning of buildings and constitutes an emergent renewable energy resource in the worldwide market. Undisturbed systems are capable of efficiently exchanging heat with the subsurface and transferring it to human infrastructures, providing the basis for the successful decarbonisation of heating and cooling demands of cities. Unmanaged intensive use of groundwater for thermal purposes as a shallow geothermal energy (SGE) resource in urban environments threatens the resources' renewability and the systems' performance, due to the thermal interferences created by a biased energy demand throughout the year. The exploitation regimes of 27 groundwater heat pump systems from an alluvial aquifer were firstly examined using descriptive statistics. Linear relationships between abstraction and injection temperatures of the systems were assessed by calculating Pearson's r correlation coefficient, and used as an evidence of thermal interferences. Then, time series of flow rate, operation temperature and energy transfer were modelled by means of spectral analysis and sinusoidal regression methods, followed by the definition of the relative exploitation patterns. The exploitation regimes examined presented a clear cooling bias and a similar cyclicality. The amplitudes correlated with the different end-user's activities (e.g. medical centres) when high frequency cycles were observed, while climatization strategies (e.g. constant flow rates and modulation of injection temperatures) did so when low frequency cycles were detected. The time series models allowed defining the relative operational pattern of a system and the groups of systems following such patterns. The biases in exploitation regimes of groundwater heat pump systems existing in Mediterranean areas require correction measures to ensure a more balanced exploitation of the SGE resources. The definition of the characteristic exploitation pattern proposed could be applied to guide resource managers by identifying unbalanced systems, understanding existent exploitation strategies and proposing corrective alternative plans.

ACS Style

Alejandro García-Gil; Corinna Abesser; Samanta Gasco Cavero; Miguel Ángel Marazuela; Jesús Mateo Lázaro; Enric Vazquez-Suñe; Andrew Hughes; Miguel Mejías Moreno. Defining the exploitation patterns of groundwater heat pump systems. Science of The Total Environment 2020, 710, 136425 .

AMA Style

Alejandro García-Gil, Corinna Abesser, Samanta Gasco Cavero, Miguel Ángel Marazuela, Jesús Mateo Lázaro, Enric Vazquez-Suñe, Andrew Hughes, Miguel Mejías Moreno. Defining the exploitation patterns of groundwater heat pump systems. Science of The Total Environment. 2020; 710 ():136425.

Chicago/Turabian Style

Alejandro García-Gil; Corinna Abesser; Samanta Gasco Cavero; Miguel Ángel Marazuela; Jesús Mateo Lázaro; Enric Vazquez-Suñe; Andrew Hughes; Miguel Mejías Moreno. 2020. "Defining the exploitation patterns of groundwater heat pump systems." Science of The Total Environment 710, no. : 136425.

Journal article
Published: 10 September 2019 in Renewable Energy
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One solution for reducing the current consumption of fossil fuels is a more frequent use of shallow geothermal energy. However, particularly regarding urban subsurface resources, increased use conflicts are predictable. Consequently, reasonable exploitation of subsurface resources requires an assessment of technologically achievable energy potentials with scientific based tools. We present application-oriented management tools which target on deriving shallow subsurface energy potentials. 3D groundwater flow and heat-transport models are used to capture groundwater flow and heat-transport dynamics on the city- and quarter-scale, 2D box models are used to quantify technically feasible extraction rates of well doublets for groundwater heat pump systems. For Basel (Switzerland), prospective large theoretical energy potentials can be derived for areas with high advective heat flux and high temperature gradients. Likewise, single city quarters are suitable for ‘active’ thermal use with well doublets, whereas thermal power potentials reach 1.2 MW. Regarding ‘passive’ installations of energy absorbers in subsurface structures located within the groundwater, energy potentials amount to 4 and up to 40 W m−2. The assessment results can be integrated into urban energy plans and support architects, city planners and potential users to acquire initial site-specific information on the technical feasibility of shallow geothermal energy systems.

ACS Style

Jannis Epting; Fabian Böttcher; Matthias H. Mueller; Alejandro García-Gil; Kai Zosseder; Peter Huggenberger. City-scale solutions for the energy use of shallow urban subsurface resources – Bridging the gap between theoretical and technical potentials. Renewable Energy 2019, 147, 751 -763.

AMA Style

Jannis Epting, Fabian Böttcher, Matthias H. Mueller, Alejandro García-Gil, Kai Zosseder, Peter Huggenberger. City-scale solutions for the energy use of shallow urban subsurface resources – Bridging the gap between theoretical and technical potentials. Renewable Energy. 2019; 147 ():751-763.

Chicago/Turabian Style

Jannis Epting; Fabian Böttcher; Matthias H. Mueller; Alejandro García-Gil; Kai Zosseder; Peter Huggenberger. 2019. "City-scale solutions for the energy use of shallow urban subsurface resources – Bridging the gap between theoretical and technical potentials." Renewable Energy 147, no. : 751-763.

Journal article
Published: 04 July 2019 in Journal of Hydrology
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The skin effect is an important issue associated with a loss of hydraulic efficiency in pumping systems. In this paper, a comprehensive study is conducted to determine how the evolution of the skin effect over time affects the productivity and functionality of brine exploitation systems in a crystalline halite aquifer. Several double-packer system tests have been interpreted via groundwater modeling to hydrogeologically characterize the investigated aquifer. A numerical groundwater flow model that accounts for the heterogeneity of the multilayer halite aquifer and the transient well skin effect on the brine exploitation system is presented to explain the continuous drawdown during three months of constant-rate brine extractions. Numerical results obtained suggested that an exponential decay function of permeability over time was required in a wellbore skin zone to reproduce numerically experimental observations during brine exploitation. The empirical exponential function obtained specifically for this case study was generalized, and coefficients considered were discussed to infer their physical and geochemical dimensions related to the mixing process triggering heterogenous reactions responsible for the hydraulic loses. Our results will be useful for predicting the spatial and temporal losses of hydraulic efficiency and for evaluating the lifetimes of brine exploitation infrastructure.

ACS Style

Alejandro García-Gil; Enric Vazquez-Suñe; Carlos Ayora; Corrado Tore; Álvaro Henríquez; José Yáñez. Impacts of the transient skin effect during brine extraction operations in a crystalline halite aquifer. Journal of Hydrology 2019, 577, 123912 .

AMA Style

Alejandro García-Gil, Enric Vazquez-Suñe, Carlos Ayora, Corrado Tore, Álvaro Henríquez, José Yáñez. Impacts of the transient skin effect during brine extraction operations in a crystalline halite aquifer. Journal of Hydrology. 2019; 577 ():123912.

Chicago/Turabian Style

Alejandro García-Gil; Enric Vazquez-Suñe; Carlos Ayora; Corrado Tore; Álvaro Henríquez; José Yáñez. 2019. "Impacts of the transient skin effect during brine extraction operations in a crystalline halite aquifer." Journal of Hydrology 577, no. : 123912.

Journal article
Published: 11 March 2019 in Water
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An actual event that happened in the Roncal valley (Spain) is investigated and the results are compared between models with and without snowmelt. A distributed rainfall model is generated with the specific data recorded by the rain gauges of the catchment during the episode. To describe the process of water routing in the hydrological cycle of the basin, a model is used based on combinations of parallel linear reservoirs (PLR model), distribution by the basin, and tip-out into its drainage network configured using a digital terrain model (DTM). This PLR model allows simulation of the different actual reservoirs of the basin, including the snow and the contribution due to its melting which, in the model, depends on the temperature. The PLR model also allows for a water budget of the episode where, in addition to the effective rainfall contribution, the water that comes from the thaw is taken into account. The PLR model also allows determination of the amount of water that exists in the basin before and after the episode, data of great interest. When comparing the simulations with and without taking into account the thawing process, it is evident that the intervention of the snow reservoir has been decisive in causing a flood to occur.

ACS Style

Jesús Mateo-Lázaro; Jorge Castillo-Mateo; José Ángel Sánchez-Navarro; Víctor Fuertes-Rodríguez; Alejandro García-Gil; Vanesa Edo-Romero. Assessment of the Role of Snowmelt in a Flood Event in a Gauged Catchment. Water 2019, 11, 506 .

AMA Style

Jesús Mateo-Lázaro, Jorge Castillo-Mateo, José Ángel Sánchez-Navarro, Víctor Fuertes-Rodríguez, Alejandro García-Gil, Vanesa Edo-Romero. Assessment of the Role of Snowmelt in a Flood Event in a Gauged Catchment. Water. 2019; 11 (3):506.

Chicago/Turabian Style

Jesús Mateo-Lázaro; Jorge Castillo-Mateo; José Ángel Sánchez-Navarro; Víctor Fuertes-Rodríguez; Alejandro García-Gil; Vanesa Edo-Romero. 2019. "Assessment of the Role of Snowmelt in a Flood Event in a Gauged Catchment." Water 11, no. 3: 506.

Journal article
Published: 01 January 2019 in Journal of Sustainability Research
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Alejandro García Gil; Miguel Mejías Moreno. Current Legal Framework on Shallow Geothermal Energy Use in Spain. Journal of Sustainability Research 2019, 2, 1 .

AMA Style

Alejandro García Gil, Miguel Mejías Moreno. Current Legal Framework on Shallow Geothermal Energy Use in Spain. Journal of Sustainability Research. 2019; 2 (1):1.

Chicago/Turabian Style

Alejandro García Gil; Miguel Mejías Moreno. 2019. "Current Legal Framework on Shallow Geothermal Energy Use in Spain." Journal of Sustainability Research 2, no. 1: 1.

Journal article
Published: 06 November 2018 in Renewable Energy
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The steady increase of geothermal systems using groundwater is compromising the renewability of the geothermal resources in shallow urban aquifers. To ensure sustainability, scientifically-based criteria are required to prevent potential thermal interferences between geothermal systems. In this work, a management indicator (balanced sustainability index, BSI) applicable to groundwater heat pump systems is defined to assign a quantitative value of sustainability to each system, based on their intrinsic potential to produce thermal interference. The BSI indicator relies on the net heat balance transferred to the terrain throughout the year and the maximum seasonal thermal load associated. To define this indicator, 75 heating-cooling scenarios based in 23 real systems were established to cover all possible different operational conditions. The scenarios were simulated in a standard numerical model, adopted as a reference framework, and thermal impacts were evaluated. Two polynomial regression models were used for the interpolation of thermal impacts, thus allowing the direct calculation of the sustainability indicator developed as a function of heating-cooling ratios and maximum seasonal thermal loads. The BSI indicator could provide authorities and technicians with scientifically-based criteria to establish geothermal monitoring programs, which are critical to maintain the implementation rates and renewability of these systems in the cities.

ACS Style

Alejandro García-Gil; Sylvia Muela Maya; Eduardo Garrido Schneider; Miguel Mejías Moreno; Enric Vázquez-Suñé; Miguel Ángel Marazuela; Jesús Mateo Lázaro; José Ángel Sánchez-Navarro. Sustainability indicator for the prevention of potential thermal interferences between groundwater heat pump systems in urban aquifers. Renewable Energy 2018, 134, 14 -24.

AMA Style

Alejandro García-Gil, Sylvia Muela Maya, Eduardo Garrido Schneider, Miguel Mejías Moreno, Enric Vázquez-Suñé, Miguel Ángel Marazuela, Jesús Mateo Lázaro, José Ángel Sánchez-Navarro. Sustainability indicator for the prevention of potential thermal interferences between groundwater heat pump systems in urban aquifers. Renewable Energy. 2018; 134 ():14-24.

Chicago/Turabian Style

Alejandro García-Gil; Sylvia Muela Maya; Eduardo Garrido Schneider; Miguel Mejías Moreno; Enric Vázquez-Suñé; Miguel Ángel Marazuela; Jesús Mateo Lázaro; José Ángel Sánchez-Navarro. 2018. "Sustainability indicator for the prevention of potential thermal interferences between groundwater heat pump systems in urban aquifers." Renewable Energy 134, no. : 14-24.

Journal article
Published: 29 September 2018 in Journal of Hydrology
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A steady increase in the consumption of pharmaceuticals and personal-care products worldwide is increasing their occurrence in the biosphere. The current study describes the abundance of 42 selected emerging organic contaminants (EOCs), including human and veterinary antibiotics, UV-filters and analgesics in the groundwater of the urban aquifer of Zaragoza (Spain), which is affected by intensive exploitation of shallow geothermal resources. The presence of groundwater heat pump systems in the aquifer studied offered the opportunity to study the occurrence of EOCs in relation to groundwater temperature and other physicochemical effects derived from this technology. Analysis of the data obtained allowed us to identify statistically significant relationships between the presence of EOCs and temperature, as well as other physicochemical and geochemical properties of groundwater. The results obtained suggest that temperature is a minor factor controlling the degradation of the organic compounds analysed compared to the oxygen input from groundwater heat pump systems which is possibly increasing the aerobic redox conditions, thus preventing the degradation of organic pollutants. Intensive use of shallow geothermal resources therefore seems to contribute in the prevalence of such compounds in the aquifer close to geothermal systems.

ACS Style

Alejandro García-Gil; Eduardo Garrido Schneider; Miguel Mejías; Damià Barceló; Enric Vázquez-Suñé; Silvia Díaz-Cruz. Occurrence of pharmaceuticals and personal care products in the urban aquifer of Zaragoza (Spain) and its relationship with intensive shallow geothermal energy exploitation. Journal of Hydrology 2018, 566, 629 -642.

AMA Style

Alejandro García-Gil, Eduardo Garrido Schneider, Miguel Mejías, Damià Barceló, Enric Vázquez-Suñé, Silvia Díaz-Cruz. Occurrence of pharmaceuticals and personal care products in the urban aquifer of Zaragoza (Spain) and its relationship with intensive shallow geothermal energy exploitation. Journal of Hydrology. 2018; 566 ():629-642.

Chicago/Turabian Style

Alejandro García-Gil; Eduardo Garrido Schneider; Miguel Mejías; Damià Barceló; Enric Vázquez-Suñé; Silvia Díaz-Cruz. 2018. "Occurrence of pharmaceuticals and personal care products in the urban aquifer of Zaragoza (Spain) and its relationship with intensive shallow geothermal energy exploitation." Journal of Hydrology 566, no. : 629-642.

Conference paper
Published: 24 August 2018 in Proceedings of the 28th International Symposium on Mine Planning and Equipment Selection - MPES 2019
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Heating and cooling using groundwater is often performed without considering potential effects on subsurface resources and the multiple interactions of different subsurface utilizations. As a result, significantly increased subsurface temperatures have been observed in many urban areas. The current uncoordinated use of subsurface resources can lead to conflicts among different users and, specifically thermal pollution may lead to large-scale thermal impacts and impairments of groundwater quality. Alternatively, current and future heat-demand in urban areas could be supplemented by recovering “waste heat” from the subsurface. Technologies for using this renewable energy resource would be particularly suitable in new buildings and infrastructures and in centers of economic growth. We show that quantitative modeling approaches can serve as the scientific basis for thermal management strategies to better understand how thermal states of urban groundwater resources develop. On the one hand, we illustrate how to derive the potential for recovering waste heat from urban groundwater resources. On the other hand we demonstrate the applicability of the ‘‘integrated relaxation factor” (IRF) concept which facilitates optimizing and locating auspicious urban settings for developing thermal management strategies. To our opinion, such strategies and advancements of practical solutions are indispensable in the debate on climate change and energy transition, as well as for reaching formulated development goals in different public initiatives such as the 2000-Watt-Society or the Europe 2020 Strategy.

ACS Style

Jannis Epting; Matthias H. Müller; Alejandro García-Gil; Peter Huggenberger. Waste Heat Recovery – Considerations for the Management of Thermally Polluted Urban Groundwater Resources. Proceedings of the 28th International Symposium on Mine Planning and Equipment Selection - MPES 2019 2018, 140 -146.

AMA Style

Jannis Epting, Matthias H. Müller, Alejandro García-Gil, Peter Huggenberger. Waste Heat Recovery – Considerations for the Management of Thermally Polluted Urban Groundwater Resources. Proceedings of the 28th International Symposium on Mine Planning and Equipment Selection - MPES 2019. 2018; ():140-146.

Chicago/Turabian Style

Jannis Epting; Matthias H. Müller; Alejandro García-Gil; Peter Huggenberger. 2018. "Waste Heat Recovery – Considerations for the Management of Thermally Polluted Urban Groundwater Resources." Proceedings of the 28th International Symposium on Mine Planning and Equipment Selection - MPES 2019 , no. : 140-146.

Journal article
Published: 01 August 2018 in Journal of Hydrology
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Different aspects of management policies for shallow geothermal systems are currently under development. Although this technology has been used for a long time, doubts and concerns have been raised in the last years due to the massive implementation of new systems. To assess possible environmental impacts and manage subsurface energy resources, collecting data from operating shallow geothermal systems is becoming mandatory in Europe. This study presents novel advances in the upscaling of operation datasets obtained from open-loop geothermal energy systems for an optimal integration in hydrogeological models. The proposed procedure allows efficient numerical simulations to be performed at an urban scale. Specifically, this work proposes a novel methodology to optimize the data treatment of highly transient real exploitation regimes by integrating energy transfer in the environment to reduce more than 90% registered raw datasets. The proposed methodology is then applied to and validated on five different real optimization scenarios in which upscaling transformation of the injection temperature series of 15-minute sampling frequency has been considered. The error derived from each approach was evaluated and compared for validation purposes. The results obtained from the upscaling procedures have proven the usefulness and transferability of the proposed method for achieving daily time functions to efficiently reproduce the exploitation regimes of these systems with an acceptable error in a sustainable resource management framework.

ACS Style

Sylvia Muela Maya; Alejandro García-Gil; Eduardo Antonio Garrido Schneider; Miguel Mejías Moreno; Jannis Epting; Enric Vázquez-Suñé; Miguel Ángel Marazuela; José Ángel Sánchez-Navarro. An upscaling procedure for the optimal implementation of open-loop geothermal energy systems into hydrogeological models. Journal of Hydrology 2018, 563, 155 -166.

AMA Style

Sylvia Muela Maya, Alejandro García-Gil, Eduardo Antonio Garrido Schneider, Miguel Mejías Moreno, Jannis Epting, Enric Vázquez-Suñé, Miguel Ángel Marazuela, José Ángel Sánchez-Navarro. An upscaling procedure for the optimal implementation of open-loop geothermal energy systems into hydrogeological models. Journal of Hydrology. 2018; 563 ():155-166.

Chicago/Turabian Style

Sylvia Muela Maya; Alejandro García-Gil; Eduardo Antonio Garrido Schneider; Miguel Mejías Moreno; Jannis Epting; Enric Vázquez-Suñé; Miguel Ángel Marazuela; José Ángel Sánchez-Navarro. 2018. "An upscaling procedure for the optimal implementation of open-loop geothermal energy systems into hydrogeological models." Journal of Hydrology 563, no. : 155-166.

Journal article
Published: 01 August 2018 in Science of The Total Environment
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The implications of intensive use of shallow geothermal energy resources in shallow urban aquifers are still not known for waterborne pathogens relevant to human health. Firstly, we hypothesized that waterborne enteric pathogens would be relatively increased in heated groundwater plumes. To prove this, microbiological sampling of 31 piezometers covering the domain of an urban groundwater body affected by microbiological contamination and energetically exploited by 70 groundwater heat pump systems was performed. Mean differences of pathogenic bacteria contents between impacted and non-impacted monitoring points were assessed with a two-tailed independent Student's t-test or Mann-Whitney U and correlation coefficients were also calculated. Surprisingly, the results obtained revealed a significant and generalized decrease in waterborne pathogen contents in thermally impacted piezometers compared to that of non-impacted piezometers. This decrease is hypothesized to be caused by a heat shock to bacteria within the heat exchangers. The statistically significant negative correlations obtained between waterborne pathogen counts and temperature could be explained by the spatial distribution of the bacteria, finding that bacteria start to recover with increasing distance from the injection point. Also, different behavior groups fitting exponential regression models were found for the bacteria species studied, justified by the different presence and influence of several aquifer parameters and major, minor and trace elements studied, as well as the coexistence with other bacteria species. The results obtained from this work reinforce the concept of shallow geothermal resources as a clean energy source, as they could also provide the basis to control the pathogenic bacteria contents in groundwater bodies.

ACS Style

Alejandro García-Gil; Samanta Gasco; Eduardo Garrido; Miguel Mejías; Jannis Epting; Mercedes Navarro-Elipe; Carmen Alejandre; Elena Sevilla-Alcaine. Decreased waterborne pathogenic bacteria in an urban aquifer related to intense shallow geothermal exploitation. Science of The Total Environment 2018, 633, 765 -775.

AMA Style

Alejandro García-Gil, Samanta Gasco, Eduardo Garrido, Miguel Mejías, Jannis Epting, Mercedes Navarro-Elipe, Carmen Alejandre, Elena Sevilla-Alcaine. Decreased waterborne pathogenic bacteria in an urban aquifer related to intense shallow geothermal exploitation. Science of The Total Environment. 2018; 633 ():765-775.

Chicago/Turabian Style

Alejandro García-Gil; Samanta Gasco; Eduardo Garrido; Miguel Mejías; Jannis Epting; Mercedes Navarro-Elipe; Carmen Alejandre; Elena Sevilla-Alcaine. 2018. "Decreased waterborne pathogenic bacteria in an urban aquifer related to intense shallow geothermal exploitation." Science of The Total Environment 633, no. : 765-775.

Journal article
Published: 11 April 2018 in Water
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Water flows in the hydrosphere through a tangled and tortuous labyrinth of ways that is the hydrological cycle. Flow separation models are an attempt to group such complexity of paths into a few components of flow and storage so as to reflect the overall behaviour of a basin. A new method of analysis and separation of flow components, based on equations of dynamic relations between Linear Reservoirs connected in Parallel (PLR models), is developed in this article. A synthesis of models based on mathematical filter equations is carried out in order to make comparisons with the proposed model. Reference is also made to the methodology of adjustment and calibration of the PLR models based on the recession curves of the real hydrographs. The models are tested with the continuous register of a basin located in the northeast of Spain. The simulations are carried out with two reservoir models (2R models), three reservoirs (3R models) and with a mathematical filter model to compare the results. With the results of the models, flow duration curves (FDCs) and storage duration curves (SDCs) were elaborated, thus allowing assessment of the origin of the water resources of the basin, a guarantee of their regulation and availability, the dynamic storage in the catchment, residence times and other features.

ACS Style

Jesús Mateo-Lázaro; Jorge Castillo-Mateo; José Ángel Sánchez-Navarro; Víctor Fuertes-Rodríguez; Alejandro García-Gil; Vanesa Edo-Romero. New Analysis Method for Continuous Base-Flow and Availability of Water Resources Based on Parallel Linear Reservoir Models. Water 2018, 10, 465 .

AMA Style

Jesús Mateo-Lázaro, Jorge Castillo-Mateo, José Ángel Sánchez-Navarro, Víctor Fuertes-Rodríguez, Alejandro García-Gil, Vanesa Edo-Romero. New Analysis Method for Continuous Base-Flow and Availability of Water Resources Based on Parallel Linear Reservoir Models. Water. 2018; 10 (4):465.

Chicago/Turabian Style

Jesús Mateo-Lázaro; Jorge Castillo-Mateo; José Ángel Sánchez-Navarro; Víctor Fuertes-Rodríguez; Alejandro García-Gil; Vanesa Edo-Romero. 2018. "New Analysis Method for Continuous Base-Flow and Availability of Water Resources Based on Parallel Linear Reservoir Models." Water 10, no. 4: 465.