Abstract
We explore the potential benefits of synergizing the operations of water and energy systems. Specifically, we tackle the challenge of reducing carbon dioxide emissions from the power grid with a focus on the water-energy systems, where water resources control the production of hydro-electricity. The need for this research stems from an important consideration: it is well known that integrating more renewables in the power grid (including hydropower, solar and wind) can facilitate decarbonization efforts; yet, it is necessary to ensure that such decarbonization efforts are able to realize their potential. Given the interdependencies of the water and energy systems, efficiently operating them as a combined system is as important as a thorough planning of the grid. This thesis addresses three important knowledge gaps with respect to water-energy systems. First, the operations of water and energy systems have dominantly been studied as two isolated systems, often neglecting the complex interdependencies between them. Second, capacity expansion in the power grid is often justified by the potential added generation. However, due to various external factors, such as transmission constraints, variability in demand, or inefficient grid operations, the actual benefits to the system may vary. The absence of a thorough analysis of the grid operations may, thus,misinform planning and investment decisions. Third, while the benefits of streamflow forecasts for reservoir operations have been well-demonstrated within the reservoir network, the understanding of its impact on power system operations is lacking. Our research advances the science in multi-sector modelling using a case study of the Cambodian grid, simulating real-life country-scale water-energy systems in our numerical models. To fill the knowledge gaps, we first developed a novel numerical modelling framework that jointly operates the water and energy models to facilitate a better representation of the system dynamics. Not only does such representation bring about better system performance, but it also introduces an element of flexibility in the combined operations. Next, we assess grid expansion decisions by evaluating power development plans using the joint operational framework. By integrating water and energy systems, synergized operations can improve operational efficiency, reduce costs, and provide environmental benefits such as reducing carbon dioxide emissions. Last, we investigate the value of streamflow forecasts and operational flexibility beyond the reservoir network by considering its effects on the power system.