Influence of selected flexibility options on the operation of fossil-fuelled power plants

The European Union committed to increase the overall share of energy from renewable sources in gross final consumption of energy and in transport to 20 %. As a consequence the national energy systems of the EU member states are in a momentous transformation process. The integration of expanding installed capacities of intermittent power producers lead to enhanced technical and economic challenges considering a stable operation of the power system. In order to meet these challenges, the flexibility of an energy system can be improved by different options, e.g. by adapting the structure and specifications of conventional power plants and enhancing storage capacities and performance. In this paper, the influence of selected flexibility options on the operation of fossil-fuelled power plants are analysed. For that purpose a fundamental model for the economically optimised schedule of dispatchable power plants, incorporating the demand of power, operating reserve and heat, has been developed. The selected options are a reduced minimum power and an enlarged rate of change of power for different types of fossil-fuelled power plants. The impact on the operation of the German portfolio is estimated by means of a sensitivity analysis for the scenario year 2015. The results indicate higher utilisation ratios, more operation hours and less start-ups for adapted power plants. Furthermore, the higher flexibility leads to reduced overall variable generation costs of the energy system.