Parameterizing the water system for the SPATNEX-WE (Spatial and Temporal Nexus -Water Energy) model. Case study for Spain

With increasing pressures on both water and energy resources, integrated planning is an important strategy to optimize resource consumption. Several existing integrated water-energy models approach the nexus from the energy sector often under-representing the water system. A detailed model characterizing the water system has been developed by the authors in another paper and has been combined with an energy model to form a single integrated water-energy nexus model. To permit smooth integration of the two systems certain spatially and temporally dis-aggregated parameters need to be provided. This study presents the parameters needed to characterize the water system for integration. Starting from a conceptual hydrological cycle the different components of the water system are investigated: from the initial stages of precipitation; through natural processes such as evapotransipration, groundwater recharge and surface water interactions; through to human interception via reservoirs, rainwater harvesting, desalination, water purification, anthropological use and recycling; and finally to runoff. Water transfers between different river basins are also considered. Spain is used as a case study to demonstrate the process which can be repeated for other countries or regions. For each water system component the energy consumption, investment and operation costs, efficiency, existing resource availability and processing capacity as well as future impacts of climate change are developed. A worked example is also developed to demonstrate the use of the parameters for each component. The paper synthesizes the data into easily accessible summary tables and along with the water model paper, provides the tools necessary for future modelers to integrate the water system into existing energy systems in sufficient detail.