Flexibilization of Coal-fired Power Plants by Dynamic Simulation

Due to the strong expansion of renewable energies, the economical and technological boundary conditions for coal-fired power plants in Germany changed significantly over the last few years. Nowadays the flexibility in power production becomes increasingly important. This increasing flexibility requirement is caused by a more and more volatile residual load through the fluctuating power output from weather-dependent renewable energies such as wind power and photovoltaics. A similar trend can be observed in other European countries and even world-wide, where the expansion of renewable energies is pursued to reduce the emission of carbon dioxide. Dynamic simulation models play a central role in improving the flexibility of power plants as they offer a tool for the evaluation and improvement of the resulting highly transient operation. This paper presents the dynamic modeling of a coal-fired power plant in Modelica/Dymola using the power plant library ClaRa (Clausius-Rankine). The focus is on the detailed non-steady-state modeling of the steam generator and the validation of the dynamic simulation model. Additionally, first results of simulation studies about the integration of a thermal energy storage and the increase of the load change rate are presented.