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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.

The use of shallow geothermal energy (SGE) resources in oceanic volcanic environments entails additional challenges when compared to continental sedimentary/plutonic settings. The efficiency of shallow geothermal heat exchangers heavily depends on the geology and hydrogeology of the terrain where are placed. Volcanic rocks in small oceanic islands (2) are the result of volcanism, erosion, and tectonic collapse. All these processes conform highly heterogeneous formations with complex hydrogeology whose thermal response to shallow geothermal systems requires a good understanding of heat transfer in such environments. The SAGE4CAN project will concentrate on SGE resource assessment taking into account heterogeneity characteristic of volcanic formations, both at local and insular scale. To this end, the Canary Islands are selected as representative volcanic oceanic islands, to define SGE implementation barriers including but not limited to (1) heterogeneities of thermal properties intrinsic to volcanic formations (volcanic dikes, red layers, landslides, etc.), (2) heat advection in the context of complex groundwater flow in the unsaturated (dominate in midlands and highlands) as well as in the saturated medium (coast), (3) enhanced geothermal gradients, (4) transient effects of urban and volcanic activity, (5) heating and cooling demand, (6) shallow geothermal energy installations design and optimization, as well as (7) energy transition strategies in energy-dependent islands. The SGE4CAN project will investigate novel approaches to overcome such boundary conditions of oceanic volcanic islands in the estimation of the renewability of the resources, developing novel procedures to conduct cost-efficient and open-access Thermal Response Tests (TRTs), investigate the performance of existent SGE systems, assessing environmental impacts associated with SGE use. The knowledge generated from this project will be used on its final stage to identify adequate strategies for the integration of SGE into heating and cooling policies and action plans, as well as to raise awareness about the technology so that it gets recognition.

[EN] The motillas are the first settlements in La Mancha during the Bronze Age. They are preferably positioned in the floodplain or the riverbed of the main rivers that cross La Mancha Plain. Researches in the motilla of Azuer (Daimiel, Ciudad Real), revealed the existence of a well (around 18 m depth) inside the fortified complex. The well object could be the calcareous levels of the Pliocene Mancha Occidental regional aquifer. It could be the Europe´s oldest groundwater exploitation system. New geological and hydrogeological investigations obtain relevant advances: all the motillas have a groundwater reservoir that could be exploited under extreme climatic conditions, by a dug well made with prehistoric methods. This confirms the hypothesis of de Motillas Culture development in during an extreme dry period, and groundwater catchment like a decisive factor., [ES] Los yacimientos arqueológicos conocidos como motillas constituyen los primeros poblamientos en la región natural de La Mancha en la Edad de Bronce. Se sitúan en la llanura de inundación o en el cauce de los principales ríos que atraviesan la Llanura Manchega. Los trabajos de investigación llevados a cabo en la motilla del Azuer (Daimiel, Ciudad Real), determinan la existencia de un pozo en el interior del recinto fortificado, de al menos 18 metros de profundidad, que podrían alcanzar los niveles calizos que forman el acuífero superior de la llanura Manchega, de extensión regional. Se considera el sistema de aprovechamiento de las aguas subterráneas más antiguo de Europa. El estudio de la geología e hidrogeología de la Mancha y las nuevas investigaciones llevadas a cabo en otras motillas, han permitido confirmar la existencia de niveles o formaciones en el subsuelo capaces de disponer de recurso de agua suficiente en condiciones de extrema sequía, a profundidad y condiciones asequibles para la época. Se confirma la viabilidad de la hipótesis de la existencia de pozos de aprovechamiento de agua en el interior de las motillas, ante un escenario climatológico de extrema aridez

© 2020 by the authors., 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., Data analyses were undertaken within the EU H2020 GeoERA project MUSE–Managing Urban Shallow geothermal Energy. MUSE received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 731166 under the terms of GeoERA programme–ERA-NET Cofund Action

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.

[EN] In the centre of Spain, Las Tablas de Daimiel National Park has been a protected natural area since 1973. During the pre-industrial era this reserve was known as the Real Dehesa de Zacatena and was enclosed by the Order of Calatrava and later managed by the Crown. Hispanic Monarchy. Due to its economic potential, the conservation of the Dehesa was one of the main concerns of its owners. Thanks to this, the historical documentation inform us about the protection measures in Zacatena since the XVIth century. The joint study of all these sources allows us to reconstruct in a very reliable way the natural landscape of the Dehesa, its extension and evolution. Visits, ordinances, descriptions complaints, and lawsuits allow us to understand one of the main pillars of the enclave: its natural patrimony, which in turn is the basis of the rich cultural and architectural heritage also preserved in the area., [ES] Situado en medio de la llanura manchega, el Parque Nacional de Las Tablas de Daimiel es uno de los pocos enclaves de nuestro país en los que se desarrolla el ecosistema de tablas fluviales. Durante la época preindustrial el lugar fue conocido como la Real Dehesa de Zacatena y fue propiedad de la Orden de Calatrava y de la Monarquía Hispánica. Dada su potencialidad económica, la conservación del lugar fue una de las principales preocupaciones de sus gestores. Gracias a ello, se custodian en los archivos numerosos testimonios que nos informan acerca del nivel de protección que, desde siglos atrás, se dio a Zacatena. El estudio conjunto de todas esas fuentes permite reconstruir de una manera muy fidedigna el paisaje natural de la dehesa, su extensión y evolución a lo largo del tiempo. Se trata de cuestiones de primer orden, que, en última instancia, permiten conocer uno de los principales pilares del enclave: su patrimonio natural, base a su vez de la rica herencia cultural y arquitectónica de la que es garante el lugar.

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-min 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.

Desde la definición de los primeros sistemas acuíferos en Sierra de Altomira hasta la actual división en masas de agua subterránea MASb, los acuíferos diferenciados en esta sierra han sufrido constantes modificaciones en su extensión y modelo hidrogeológico conceptual. Incluso en la actualidad se plantean incertidumbres con respecto a su compartimentación interna a nivel hidrogeológico. A partir de un profundo análisis estructural sobre el origen y formación de las estructuras sedimentarias que hoy constituyen los niveles permeables de la MASb, se ha correlacionado el modelo tectónico resultante con la hidrogeología de la MASb Sierra de Altomira en general, y con su posible compartimentación interna en particular. El modelo estructural obtenido ha permitido distinguir diferentes zonas que, a escala local, presentan un comportamiento hidrogeológico diferente. La compartimentación propuesta se realiza a nivel regional, diferenciando dos grandes bloques estructurales: septentrional, meridional y, una escala mayor, con la definición de la Unidad Hidrogeológica Básica (UHB) como unidad mínima divisible en la que se identifican todos los componentes del modelo hidrogeológico conceptual. Esta división supone un importante punto de partida para la posterior interpretación del funcionamiento hidrogeológico local de la MASb Sierra de Altomira, si bien esta propuesta requiere de estudios complementarios para un mejor conocimiento de su hidrodinámica., Instituto Geológico y Minero de España, Madrid, Instituto Geológico y Minero de España, Unidad de Valencia

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. © 2018 Elsevier Ltd, This work was performed by the Geological Survey of Spain (IGME) under the Cooperation Agreement framework between IGME and the Ebro Hydrographic Confederation (CHE) for the specific arrangement entitled “The application of a groundwater flow and heat transport numerical model for the simulation of management strategies of geothermal installations in the city of Zaragoza”. Alejandro García-Gil gratefully acknowledges MIKE by DHI for the sponsored FEFLOW license.

A steady increase in the use of shallow geothermal energy can be observed worldwide in past years. In order to highlight the necessity of a specific detailed legal framework for shallow geothermal energy systems, an overview of the current legal framework in Spain is carried out in this paper. Findings show complex legislation at the national level and a high diversity among regional governments in Spain. There is no legally binding definition of shallow geothermal energy resources and the deep geothermal approach of the past is embedded in the legislation inherited from 40 years ago. In consequence, the lack of specific legislation makes the licensing process of systems an effective barrier for the further development of the market, thus indicating the need for a common approach. This work highlights the need for a shallow geothermal energy management framework structure and a governance model based on an adaptive management approach, including both management planning and implementation as well as control cycles.

Se presenta un estudio detallado sobre los colapsos del terreno, que se han producido en los últimos años en la zona central de la Masa de Agua Subterránea Mancha Occidental I, provincia de Ciudad Real. El principal origen de los colapsos es el hundimiento del techo de cavidades kársticas, como resultado de un rápido e inusual ascenso piezométrico, debido a las abundantes e intensas precipitaciones, como las que tuvieron lugar en el periodo húmedo, 2009-2013, lo que trajo consigo un lavado del sistema kárstico, la circulación del agua por sumideros y canales preferentes, así como la propia disolución del material calcáreo. Esta fase de ascenso piezométrico vino precedida de un descenso continuado de los niveles, motivada por la secuencia seca 2000-2009 y el intenso aprovechamiento de las aguas subterráneas mediante bombeos. Para conseguir un óptimo conocimiento del área de estudio, se ha realizado un importante trabajo de localización, medición y clasificación de cada uno de los hundimientos. Unido a ello, se han recopilado, ampliado y actualizado los datos de piezometría, con un nivel de detalle muy importante. Se han podido diferenciar cuatro tipos de colapsos: colapsos aluviales (entre los que figuran los relacionados con las turberas), colapsos en zonas de dolina, colapsos lagunares y colapsos de tipo intermedio. Se ha observado que, con el paso de los años, los hundimientos que se producen tienen menores dimensiones. Por último, se han deducido las zonas que presentan una mayor susceptibilidad para que se produzcan nuevos colapsos en lugares como el cauce del río Guadiana, las áreas lagunares y algunas zonas de dolinas., Centre de Recerca Ecològica i Aplicacions Forestals, Universitar Autònoma de Barcelona, España, Instituto Geológico y Minero de España, España, Centro de Interpretación y Documentación del Agua y los Humedales Manchegos, España

p.885-911, Los ojos del Guadiana y los ojos del Gigüela son un conjunto de manantiales que aportaban agua subterránea a sus respectivos cauces en condiciones naturales. Los del Guadiana constituyen el propio nacimiento del río, mientras que los del Gigüela surgían en el tramo final. A partir de la década de los 80 del pasado siglo la intensa explotación a la que fue sometido el Sistema Acuífero 23 generó un descenso del nivel piezométrico generalizado que, a su vez, provocó la desecación de dichos manantiales. Tras el periodo húmedo 2009-2013 se produjo una lenta recuperación de los acuíferos de las masas de agua subterráneas (MASb) centrales del Alto Guadiana, reflejado en un ascenso de niveles continuado hasta 2014-2015, pasando a continuación a registrarse un nuevo periodo de ligero descenso piezométrico. Los ojos del Guadiana resurgieron en enero de 2012, en pleno periodo de recuperación del acuífero, mientras que los ojos del Gigüela no presentaron agua hasta 4 años después, en diciembre de 2015, tras dos años hidrológicos secos y en periodo de descenso piezométrico incipiente. La evolución hidrogeológica registrada en el periodo diciembre 2009-febrero de 2016 da lugar al proceso de recuperación de los acuíferos de la Llanura Manchega, consecuencia del periodo húmedo mencionado. El desfase temporal en la presencia de agua entre ambos conjuntos de manantiales está relacionado con las características geológicas e hidrogeológicas del acuífero carbonatado Plioceno, concretamente con su morfología sedimentaria en el sector occidental. La evolución piezométrica de la Llanura Manchega en los últimos siete años describe el proceso de recuperación parcial de las MASb centrales, desde sus niveles más profundos hasta los más someros, en el sentido de avance natural del agua subterránea este-oeste., Instituto Geológico y Minero de España (IGME)

Los inicios de la caracterización de la Cultura de las Motillas se sitúan hace cuatro décadas. Desde entonces diversas universidades y expertos han intentado encontrar explicación a las causas del origen, evolución y desaparición de este singular grupo humano que habitó La Mancha durante la Prehistoria Reciente. Los últimos avances en la investigación permiten plantear tres datos de importancia para el tema. En primer lugar, las motillas pueden ser en realidad el más antiguo sistema de captación de agua subterránea del accidente europeo. En segundo lugar, la implantación de esta red de pozos pudo estar relacionada con una crisis climática que hizo desaparecer de forma generalizada las aguas superficiales durante un largo periodo de tiempo, debido al Evento Climático 4.2 ka BP. En tercer lugar, las motillas son tells muy similares en lo formal a los túmulos funerarios. Acaba de ser definido un horizonte funerario tumular asociado a la Cultura de las Motillas que era desconocido por completo. Este trabajo aporta, además, el inventario actualizado de todas las motillas conocidas, The investigation of the Culture of the Motillas began four decades ago. Since then, various scholars have tried to ellucidate the origin, development and disappearance of this singular human group that existed during the Late Prehistory in La Mancha (South Central Plateau, Spain). As a result of recent research, three important issues about this question have arisen. First, the Motillas could possibly be the oldest system of underground water collection in Westerm Europe in Europe. Second, the implementation of this network of wells could be related to a climate crisis that could have dried the surface water for a long period of time, related to the 4.2 ka BP Climate Event. Third, the Motillas are tells, very similar in form to burial mounds. Funerary tumuli associated with the Culture of the Motillas have recently been described. This work also provides an updated inventory of all known Motillas

Estudios recientes indican que las motillas, asentamientos de la Edad del Bronce de La Mancha, pudieron ser las más antiguas captaciones de agua subterránea en la Península Ibérica. Pero ¿por qué no existen motillas en el Campo de Montiel, territorio ubicado tradicionalmente en esta área cultural? En Castillejo del Bonete, sitio arqueológico situado en esa comarca, existe una cueva que fue utilizada y sellada durante la Prehistoria Reciente. Se presenta ahora la primera investigación paleohidrogeológica interdisciplinar en La Mancha, que ha analizado manantiales y niveles de agua subterránea del acuífero de Campo de Montiel, así como el interior de la sima de Castillejo del Bonete. Las conclusiones avanzan una relación entre el sustrato hidrogeomorfológico y la distribución espacial de las motillas. Además permiten descartar que la sima de Castillejo del Bonete fuera utilizada como mina o como acceso al acuífero, dos de las hipótesis de trabajo planteadas. De ese modo cobra fuerza que Castillejo del Bonete fuera un excepcional monumento funerario y simbólico durante el Calcolítico y la Edad del Bronce, perteneciente a una nueva clase de asentamientos desconocidos hasta ahora en el grupo cultural de la Edad del Bronce de La Mancha., Esta publicación ha sido autorizada por la Dirección General de Cultura de la Junta de Comunidades de Castilla-La Mancha (Exp. Cult. 12- 1478)