Assessment of the water-energy-food nexus in the life cycle of energy products

Abstract

Given the urgent need to achieve energy security and transition from conventional to renewable energy sources, the energy sector is expanding rapidly. However, this growth often involves trade-offs with food and water resources. One way to address this complex interplay is to adopt the Water-Energy-Food nexus within a Life Cycle Assessment. This approach allows the analysis of interrelationships among the three sectors, aiming to foster synergies and minimize trade-offs. While numerous indicators exist to quantify the water-energy relationship, no similar approaches for the energy-food relationship could be found. To bridge this gap, in this paper, we introduce a novel indicator that measures the amount of food that could be produced causing the same land use impact in form of biodiversity damage as 1 MJ of the energy product. Together with another existing indicator that measures the water scarcity footprint per megajoule, a new framework for the analysis of the Water-Energy-Food (WEF) nexus of energy products is developed. Additionally, we present an optional net factor for both indicators. This factor helps to consider the energy use within the product's processes, contributing to a more comprehensive analysis. In our case study, we implement the outlined framework by examining biodiesel production in Argentina. We specifically analyze the impacts of two distinct agricultural technologies—Early and Late Soybean—on the Food and Water sectors. Our findings reveal that for every megajoule of the evaluated product, one could produce 62 or 93 kcal of food causing the same species loss. Additionally, the production process incurs a water scarcity footprint of 6.5 or 6.8 liters per megajoule, depending on the technology used. The proposed framework offers a means to mitigate the water and land use impacts associated with energy products. Consequently, it has the potential to enhance the WEF nexus.