Flexible future of power plants - challenges and solutions

The share of energy produced from renewable resources is rapidly growing. Future conventional power plants will increasingly shift from base-load to more fluctuating load-follow operation, to balance the supply and demand in the grid. This will mean more frequent and faster load changes, decreasing minimum loads and more start-ups and shutdowns than assumed in design. The resulting challenges can be severe for effective operation aiming to avoid excessive cost from increased rate of damage to the plant equipment and from increased emissions at part-load and transient operation. At the same time, fuel feedstocks are increasingly diverse, containing e.g. different types of biomass and low rank coals, allowing the use of local resources and reduced dependence on imported fuels. The fuel changes may not be directly visible in operational parameters, but fouling and corrosion tend to increase material wastage and risk of tube leakage, operational problems and unplanned shutdowns. The future roles of thermal power plants will also frame the economic conditions of their survival. This paper aims to describe the challenges and possible solutions for successful operation of flexible power plants.