Optimal sizing toolbox for energy generation and storage for a nuclear hybrid microgrid

Abstract

Background In recent years, renewable energy sources, such as wind, have contributed to a decrease in grid stability. This has created the need for flexible and reliable back-up energy generation. Currently this role is fulfilled by natural gas-fired power plants that are able to quickly adjust power output based on present needs. Nuclear power presents an option for a clean and reliable alternative to these natural gas-fired power plants. However, nuclear power alone is unable to provide flexible enough power generation to fill this role. Instead, nuclear power plants must be combined with strategically sized energy storage systems to effectively complement the renewable power generation. Grids such as these are generally simulated using deterministic models which are unable to account for quickly fluctuating wind power generation. This in turn creates unsafe ramp rates for the nuclear power plant. Methods The approach taken in this paper utilizes a continuous-time stochastic model to simulate a grid with wind generation, nuclear power, and an energy storage system as the only energy sources. This paper focuses on this model and a development of a GUI to form a grid sizing toolbox. This toolbox was then demonstrated with an isolated microgrid using year-long wind and load data. Wind penetration, nuclear ramp rate limitations, and storage types were all varied to observe different scenarios and determine optimal storage sizing. Results There were several outcomes from this study that can inform grid planning. Nuclear power plant size trends downwards with greater wind power generation. However, high variability of wind power limits the size reduction. Nuclear capacity factor is between 41% to 57%, dropping further as wind penetration was increased. This highlights the difficulty of maintaining high utilization in these scenarios. Conclusions All storage types had similar performance in all categories except size, in which pumped hydroelectric and compressed air storage required smaller storage sizes.