Associate Professor University of Notre Dame, Indiana, United States
Abstract Submission: As decarbonization proceeds, interest in non-fossil fuel chemical energy carriers grows. Advantages of chemical energy carriers include the ability to store fuels, transport them in small quantities, and operate independently of electricity grids. When they are manufactured from inputs with minimal greenhouse gas and other environmental impacts, they can also contribute to environmental goals. Simultaneously, their particular characteristics can ease or enable certain types of activities that are challenging or impossible to perform with electricity (including via batteries). As such, many decarbonization models suggest a large role for such resources, including hydrogen, sustainable aviation fuels, ammonia, and others. At the water-energy nexus, however, it is essential to investigate the potential water demand associated with the widespread manufacture of clean chemical energy carriers, especially because many are derived directly from water (e.g., electrolytically from hydrogen) or from water-intensive biofuels. Energy intensity can also be high. Water demand for these carriers might not be a major challenge if they are applied judiciously, primarily in settings where alternatives are truly unavailable or extremely difficult, but current US policy incentives encourage major growth in production. These production-maximizing approaches could lead to sufficient scale to pose real constraints on water availability, particularly if these chemical energy carriers become nondiscretionary demand due to their tight integration with energy service needs.
