Integrating water and energy models for optimal long-term resource management

Introduction

Availability of and access to water and energy are key ingredients of economic and social development. Unfortunately, half the world's population still lack access to both freshwater and basic energy services. Future predictions show that the situation may become worse, with about a 40% increase in energy demand and 30% increase in water demand by 2040. In addition, water and energy are highly interdependent, with water needed in all phases of the energy lifecycle and energy needed in all phases of the water lifecycle. While recent years have seen an increasing number of studies on the water-energy nexus, the research is focused on scattered individual areas of the nexus, each important in their own right. With increasing evidence of the different interdependencies of the water and energy systems there is a need to develop applicable holistic water-energy nexus methodologies to maximize the possible co-benefits from integrated planning.

Methods

After a literature review, several key elements were identified as important factors to consider in future water and energy integrated models in order to capture critical feedbacks and interdependencies. This includes consideration of different power plant cooling technologies, climate change impacts, a representation of the water infrastructure system and its corresponding energy consumption, physical water resource limitations, and adequately synchronizing the water and energy systems both spatially and temporally. A partial-equilibrium linear programming energy model had already been developed and a spatially and temporally compatible water resource and infrastructure model was developed in the General Algebraic Modeling System (GAMS). The two models were linked based on shared multi-use reservoirs, water consumption by the energy system, energy consumption by the water system, and a global objective function which is capable of optimizing multiple objectives depending on the needs of the users. The models were developed for the region of mainland Spain.

Results

Preliminary results show that the interdependencies of water and energy systems can have considerable impacts on future resource management strategies and technology choices. For example, certain policies which may favor water-intensive energy technologies like biofuels will result in increasing competition for limited surface water resources in agriculture basins, leading to increases in alternative energy-consumptive water-processing technologies such as desalinization and water transfers.

Conclusions

While the integrated model is still being calibrated and checked, even preliminary results show that the water-energy nexus will be a crucial part of future resource management strategies and it is clear that integrated, holistic management approaches will be the key to sustain the kinds of lifestyle patterns and population increases that are predicted in the face of diminishing natural resources and climate change.

Please note these Proceedings have received limited or no review from supervisors and IIASA program directors, and the views and results expressed therein do not necessarily represent IIASA, its National Member Organizations, or other organizations supporting the work.

Last edited: 03 February 2016