Advantages of geothermal energy in the power supply of large-scale desalination and wastewater treatment processes. A case study

Abstract

Achieving sustainability in the water-energy nexus is a major challenge in regions with high dependence on desalination processes. These processes consume significant amounts of energy and have a high specific weight in electricity systems, especially those that are not large in size. The in situ use of non-dispatchable renewableenergies in desalination processes has been widely studied in the scientific literature. In this paper, a method isdeveloped to identify the technical and environmental advantages of the direct interaction of high-enthalpy geothermal energy, as a dispatchable renewable energy source, in continuous water treatment processes in comparison with non-dispatchable renewable energy sources. The method is applied to a case study in the Canary Islands. The incorporation is proposed of an on-grid renewable energy system to supply a set of hydraulic complexes equipped with desalination and wastewater treatment plants. Different simulations are carried out, and trade-off solutions are identified and compared on the basis of the results obtained for different technical, economic and sustainability parameters. It was found that the geothermal energy requires less renewable energy effort to cover the demand of the water processing systems, for example 4 times less power than solar PV, as well as 6.5 times less land area. The latter additionally contributes to the sustainability of the territory.