The Role of Geothermal Heat Pump Systems in the Water–Energy Nexus

Unplanned rapid urbanization is considered to be one of the major drivers of change in cities across the world. It leads to an inadequate transformation of urban environments, affecting strategic energy and water management infrastructure, resulting as well in an escalation in energy demand and a greater pressure on stormwater facilities. It is estimated that one third of the total energy demand in the European Union (EU) is associated to air-conditioning in buildings, whilst conventional drainage systems have become unsustainable under the current scenario of climate change. In this context of uncontrolled challenges, the EU is encouraging the incorporation of Nature-Based Solutions (NBS) in order to promote resilient infrastructure and to reduce instability. Sustainable Drainage Systems (SuDS) have been selected as key Stormwater Control Measures (SCM), contributing to a paradigm shift in urban water management. As the need for multifunctional spaces evolves due to the lack of urban land, SuDS are increasingly becoming a potential asset to house renewable energy structures, helping to develop the water–energy nexus. Thus, this chapter deals with the opportunities arising in this new research line combining surface geothermal energy systems and SuDS. Both laboratory and field experiences have been analyzed, compiling the lessons learned, identifying the present knowledge gaps, and proposing the future prospects for development. Therefore, paving the way for the effective combination of both technologies.