Enhancing Resilience and Self-Sufficiency in the Water–Energy–Food Nexus: A Case Study of Hydroponic Greenhouse Systems in Central Greece

The water–energy–food (WEF) nexus provides a critical framework for addressing the interconnected challenges of resource scarcity and sustainability in the face of global population growth and climate variability. This study investigates the application of a WEF nexus approach within the operation and management of a hydroponic greenhouse unit in Central Greece, with the aim of enhancing the unit’s energy autonomy and resource sufficiency. Hydroponics, a soilless cultivation method, optimizes water and land use but relies heavily on energy inputs, necessitating integrated solutions. Through the case study approach, we analyze the unit’s resource dynamics per hectare of water (68 MWh equivalent from desalination), energy (125 MWh or 321 GJ/ha plus 74.5 GJ/ha for fertigation), and food production (~295 tons, which contains 50,250,000 kcal and corresponds to 210 GJ) and propose technical solutions: photovoltaic panels as greenhouse coverings and water rain harvesting regulated with a small reservoir. These innovations could reduce external energy dependency by 90–95% and water use by 25–35%. Energy efficiency is quantified using the energy ratio (ER) and net energy gain (NEG), while resilience is assessed via system reliability under resource variability. Conclusively, this study illustrates how a nexus-based approach can effectively upgrade systems into climate-resilient, resource-efficient models as the abundance or scarcity of one source affects the availability or limitation of the others. Overall, the approach presented in this study could also be used to safeguard the supply chains in megacities.