Masoumeh Khalkhali
University of New Hampshire
Ms. Masoumeh Khalkhali is a second year PhD student at the Civil and Environmental Engineering Department of the University of New Hampshire. She completed her BS and MS studies in the University of Tehran. She worked on “Decision support system model development of irrigation and drainage networks” in her master’s thesis. She has worked with consulting firms in Iran on the design and maintenance of agricultural hydraulic networks as a project manager. She is now research assistant in "Critical Resilient Interdependent Infrastructure Systems and Processes (CRISP)" project funded by the National Science Foundation.
Water and energy are interconnected in the modern world: neither resources can be provided without the other. Facing future climate, population, and policy changes, it is important to understand the constantly changing,... [ view full abstract ]
Water and energy are interconnected in the modern world: neither resources can be provided without the other. Facing future climate, population, and policy changes, it is important to understand the constantly changing, tightly coupled, nonlinear, and feedback-governed water-energy nexus to inform integrated management of these two resources. Previous approaches such as water and energy audits and life cycle assessment, while providing important insights into the significance of water-energy nexus, are incapable of capturing the feedback connections and predicting future trends in the complex water-energy systems.
To address these limitations, a system dynamics model (SDM) coupled with a hydrologic model and an energy generation model was developed in this study to investigate the water-energy nexus. System dynamics modeling is a computer-aided approach that uses a set of differential equations to describe systems with interdependence and circular causality. The completed SDM was then applied to the Massachusetts Water Resources Authority (MWRA) to investigate the tradeoff, synergy, and future trends of water supply and hydropower generation in the MWRA under population growth and climate change. The MWRA is the primary water supplier of the Greater Boston area with two water reservoirs and two hydropower plants. Hydropower is generated from water transferred between the two reservoirs and from the reservoirs to the treatment facilities.
Historical water storage and water level of the two reservoirs were first simulated based on the temporal mass balance of all the inflows (e.g., precipitation, river inflow, diverted water from the upstream reservoir) and outflows (e.g., surface evaporation, released and spilled water) of each reservoir. Historical inter-reservoir transfer, downstream release from reservoirs, and inter-basin diversion were obtained from the MWRA. Streamflow was simulated using a hydrologic model (the abcd model) with historical temperature and precipitation data obtained from the National Oceanic and Atmospheric Administrative. Outcomes from the abcd model were calibrated and validated using the gaged streamflow measurements obtained from the United States Geological Survey. Once the water SDM is completed and validated, energy generation in the two hydropower stations was modeled based on the turbines’ characteristics, inter-reservoir transfer rate, and the available head calculated from the water SDM.
It was found that population growth or a higher water demand does not necessarily result in a higher electricity generation. This is because of the significant amount of bypass when the water demand surpasses the turbines’ functional limits. The result also shows that higher temperature can result in lower water levels in the reservoirs as well as a higher water demand from the system, both of which adversely affect the energy generation. In addition, it was found that considering energy supply and demand of the system as well as water supply can be more beneficial for MWRA.
• Complexity, resilience and sustainability , • Sustainable energy systems , • Sustainable urban systems
