Shallow Geothermal Energy Resources and Thermal Impacts in Buenos Aires City, Argentina

MAR ALCARAZ; LUIS S. VIVES

Congress on Research, Dvelopment, and Innovation in Renewable Energies

Springer

Lugar: Cham; Año: 2022; p. 107 - 119

Improving the quality of life inherently entails an increase in the capacity to consume goods and services, including the demand for energy. This fact is verified each year in different regions of Argentina, particularly in the Autonomous City of Buenos Aires (CABA), where the current energy supply infrastructures are not sufficient to satisfy this demand [1].The implementation of renewable energies (RES) is a challenge in Latin American countries [2–4], particularly in Argentina, where the conventional sources of energy are predominant [5] and the economic and social situation is reticent to changes [6]. According to the official statistics of CABA,1 the consumption of electricity in 2021 was 10.3 GW. It has been continuously growing since 1996.Shallow geothermal energy (SGE) can support the transition to a RESmarket because it has great versatility. This is mostly used for air conditioning (heating and cooling) with a Borehole Heat Exchanger (BHE) and a Ground-Source Heat Pump (GSHP). It can be implemented both in large areas, such as: hospitals, hotels or university centers, as well as in single-family homes; in buildings already built through specific adaptations or in new construction projects; and also in industrial farms, such as greenhouses or livestock farms. As suggested by different authors [7, 8], the generation and dissemination of SGE potential (SGEP) maps is a key point when promoting and developing this alternative renewable energy source. This must be the first step in undertaking the exploitation and management of this resource, as shown by the numerous mapping works [9–14], and references therein. In all these cases, GIS technology (Geographic Information Systems) is the one chosen to undertake the tasks of mapping and data management [9]. appliedGIS based on the methodology proposed in [15], based on Specific heat extraction values for each lithology [10]. resolved the conduction-advection heat transport solution defined by [16] to create maps of SGEP. Whereas [11, 12] used a geodatabase to characterized the aquifers, [13] interpolated the thermal conductivity from soil properties to evaluate the Very Shallow Geothermal Potential forEurope [14]. used GIS tech to calculate the greenhouse gasses emissions of SGE exploitations.On the other hand, numerous authors highlight the importance of considering the groundwater flow when estimating the SGEP [16–19]. As mentioned before, [16] developed an analytical solution for the conduction-advection heat transport equation, which denotes the relevance of considering the groundwater flow [17]. showed that advection of heat by groundwater flow significantly enhances heat transfer in geologic materials with high hydraulic conductivity [18]. included dispersion of heat induced by groundwater flow [19]. concluded that the presence of a groundwater flow could improve the long-term operation conditions. Thus, a comprehensive hydrogeological study is essential to obtain adequate SGEP values.The objective of this research is to estimate the SGEP based on a detailed thermo-hydrogeological model of the Autonomous City of Buenos Aires. It includes the groundwater velocity effects and the spatial variation of thermal properties. In previous works [20, 21], a preliminary evaluation of SGEP for borehole heat-exchangers (BHE) was estimated considering homogeneous values for thermal properties of the ground for the whole area of the Matanza-Riachuelo river basin at a regional scale. We present here the final version where the lithological description of existing boreholes was considered to create maps of spatial variation for thermal conductivity and heat capacity variables, focusing on the Autonomous City of Buenos Aires. Moreover, the thermal impacts are evaluated for the first time as the size of the thermal plume.