The Compatibility of Geothermal Power Plants with Groundwater Dependent Ecosystems: The Case of the Cesine Wetland (Southern Italy)

Abstract

Abstract:The Cesine Wetland, located along the Adriatic coast, was recognized as a Wetland of International Interest and a National Natural Park. Managed by the "World Wide Fund for nature" (WWF), it is considered a groundwater dependent ecosystem which is affected by seawater intrusion. The site was selected to test the environmental compatibility of a low-enthalpy geothermal power plant (closed loop) operating in the aquifer saturated portion with purpose to improving the visitor centre. For this purpose, the long-lasting thermal impact on groundwater was assessed using a multi-methodological approach. The complex aquifer system was carefully studied with geological, hydrogeological and geochemical surveys, including chemical and isotopic laboratory analyses of surface water, groundwater and seawater. The isotopes δ 18 O, δD, δ 11 B, and 3 H were useful to clarify the recharge contribution, the water mixing and the water age. All information was used to improve the conceptualization of the water system, including aquifers and the boundary conditions for a density driven numerical groundwater model. The purpose was to forecast anthropogenic thermal groundwater variations up to 10 years of plant working before the plant realization and to validate the solution after some working years. All results show the environmental compatibility notwithstanding the peculiar ecological environment.

Deep geoelectrical investigation to bound a coastal thermal outflow area

“…The offshore equivalent of the Salento Calcarenites are well imaged in the seismic lines and form a series of prograding units settled during a forced regression (Aiello and Budillon 2004). In the studied area, groundwater flow within a deep aquifer that occurs within the intensely fissured and karstified Altamura Limestone, Castro Limestone and Porto Badisco Calcarenites (Romanazzi et al 2015, De Giorgio et al 2018. These units have the same hydrogeological characteristics and play an important common role in the groundwater circulation.…”

Improving Regulation and the Role of Natural Risk Knowledge to Promote Sustainable Low Enthalpy Geothermal Energy Utilization

“…In the case of LEG with higher potential impacts or in the case of installation in areas with some potential hazards or in natural protected areas, it seems relevant the mandatory request of ground response tests (GRTs), detailed hydrogeological site studies, and 15-year transient thermal modelling simulation [23]. The request of environmental or hydrogeological monitoring during the operation period could be an optimal solution for very large LEG systems, or in the case of public concern about potential hazard, as in the case of natural protected areas.…”

A Fourier Series Solution for Transient Three‐Dimensional Thermohaline Convection in Porous Enclosures

“…With these boundary conditions, two circulation flows arise on two different planes and a 3‐D investigation becomes inevitable. Such a configuration can be found in several applications as in geothermal systems in coastal aquifers or in islands (e.g., GEOTREF project: https://geotref.com; De Giorgio et al, 2018; Navelot et al, 2018; van Lopik et al, 2015) where the sea/ocean can generate a salinity gradient and geothermal wells create a thermal gradient (Figure 1b). It is also important in applications involving variable density flow related to two different solute compositions in which the solute gradient can be horizontal and crossed.…”