ABSTRACT
In this chapter the factors responsible for the unfavorable operational characteristics of coal-fired units have been discussed. The coal-power industry in Poland is used as a case study. The impact of the new investments in the field of wind energy on the economics of coal-fired units is reviewed. For power systems based mainly on coal, the periodically appearing high power generation of wind turbines leads to the risk of losing the continuity of energy production. Additionally, it leads to decrease of annual average efficiency of fuel conversion and higher emission of harmful substances. The authors point out that in the era of renewable energy development for maintaining a high level of energy production based on coal, in addition to the implementation of energy storage systems, the increase of flexibility of coal-fired units is required. The chapter presents the basic ways to improve the flexibility of coal-fired blocks that can be used within existing units and discusses the factors that determine flexibility.
