CHALLENGES FOR COAL BASED ELECTRICITY GENERATION IN ENERGY SYSTEMS WITH HIGH CAPACITY OF VARIABLE RENEWABLE ENERGY SOURCES

摘要

The market conditions for thermal power plants in Europe are changing rapidly with ever increasing share of the supply provided by variable renewable energy sources. Operators are struggling to keep up with the new conditions in a system where power plant flexibility has historically been of less importance. This is however starting to change and in line with this development, the power industry is increasingly interested in R&D work on improving plant flexibility. Based on interviews with several experts within the power industry, a literature review and dynamic power plant modelling this work highlight and discusses important areas of development for flexible coal-based power generation. Four flexibility aspects were specifically emphasized by the experts interviewed; turn-down, part-load efficiency, start-up times and ramp rates. All experts interviewed regarded retrofits of existing plants to be a more likely development than building of new flexible plants and at present, it seems as the focus is mainly to use all low-cost options for increasing plant flexibility. The extent of beneficial effects from increased plant flexibility for both the plant operator, and the electricity system is still unclear. A techno-economic modeling study of power systems combined with dynamic power plant modeling, taking into account the possible development in plant flexibility as highlighted in this work, could further provide valuable insight and underline which flexibility aspects are of most importance to develop.