Dynamic Modeling, Analysis, and Control of Integrated Electricity and District Heating Systems

Abstract

Some of the main challenges with more efficient and cleaner energy systems include the development of Integrated Electricity and Heating Systems (IEHSs). Thus, the proposed research explores IEHSs in the context of Microgrids (MGs) and Bulk Power System (BPS), including the integration of Small Modular Reactors (SMRs) to provide both electricity and heat. In this context, the main goal is to study dynamics and control of IEHSs, with an emphasis on District Heating Networks (DHNs) for efficient energy use. Thus, the proposed work aims to support a cleaner energy transition in both remote communities and urban areas through the use of IEHSs, focusing on two key objectives, namely, developing a comprehensive dynamic models of a combined DHN and Electric Power Network (EPN) to study energy exchanges between these systems, and the provision of ancillary services for power grids for both BPSs and MGs.

A dynamic DHN and EPN model is first developed for MGs, considering all relevant heating and electricity system details, but especially soil limitations, extreme low temperatures, and piping insulation to minimize heat loss. The accurate sizing of the Heat Pumps (HPs) based on thermal load requirements, weather conditions, and consumer profiles is also discussed, proposing a demand management control to enhance MG primary frequency regulation, which facilitates the integration of variable Renewable Energy Sources (RESs) in power grids. The proposed dynamic models are applied, tested, and validated in a realistic community MG based on a remote community EPN located at Kasabonika Lake First Nation (KLFN) in Northern Ontario. It is shown that the DHN facilitates the proper integration of RESs in isolated MGs through the development of novel EPN control systems.

The presented research also studies IEHSs to serve a broader geographical region beyond MGs. Thus, it proposes to investigate the impacts of IEHSs on the dynamic operation of the BPS in collaboration with Ontario’s Independent Electricity System Operator (IESO), using SMRs as the primary source for both electricity and thermal energy demand. For this purpose, a comprehensive dynamic model of a boiling water SMR power plant, incorporating all essential components, including the reactor, steam turbine, and steam flow control system, is first developed to evaluate its practical application in power grids. Unlike previous studies that focus on individual elements, this work proposes the first full system model with direct steam expansion, capturing key thermal-hydraulic dynamics of the reactor, such as pressure variations and two-phase drift velocity, to improve simulation accuracy. The incorporation of a DHN is then studied, demonstrating that the reactor efficiency can be improved by enabling combined heat and power generation and the provision of ancillary services, which collectively would increase the overall performance and efficiency of the BPS.

The proposed SMR dynamic models are integrated into a widely used power system analysis tool to assess their dynamic performance and impact on Ontario’s BPS. The results highlight the operational flexibility and frequency regulation potential of the BWRX-300, demonstrating its feasibility for practical deployment in modern power grids while also discussing the potential challenges of integrating it within large-scale power networks. Furthermore, the results of the SMR-based DHN models highlight the strong potential of SMRs for cogeneration applications, demonstrating their operational flexibility in practical settings and illustrating a significant reduction in energy consumption compared to heating systems based solely on HPs, which is the current trend.