DIW & PIK publish in "Nature Energy"

Copyright Harald Richter


Researchers of DIW Berlin and the Potsdam Institute for Climate Impact Research (PIK) have published a joint article on start-up costs of thermal power plants in the journal Nature Energy. Before power plants fueled by coal, natural gas or oil are able to generate electricity, they have to be started up to a minimum load level. This incurs costs related to additional fuel consumption as well as wear and tear. In the article, it is investigated how these costs may develop in Germany in the context of renewable expansion up to 2030. Start-up costs increase because of more volatile electricity supply from wind power and solar photovoltaics, but they remain on a rather low level. Different drivers can be separated: start-up costs not only increase because of renewable expansion, but also because of increasing fuel and carbon prices, for example. Other factors have an opposite effect: “Additional storage and flexible electricity generation from biomass both decrease start-up costs” says Dr. Wolf-Peter Schill, first author of the article. Co-authors are PIK researchers Dr. Michael Pahle and Christian Gambardella. The study draws on an open-source power market model. The model code and all input parameters are available under an open license in a public repository. “Our consequent open-source approach ensures a high level of transparency” says Schill. The article originated from a joint research project by PIK and DIW Berlin which was supported by Stiftung Mercator and Agora Energiewende. Abstract of the article: The emerging literature on power markets with high shares of variable renewable energy sources suggests that the costs of more frequent start-ups of thermal power plants may become an increasing concern. Here we investigate how this develops in Germany, where the share of variable renewables is expected to grow from 14% in 2013 to 34% in 2030. We show that the overall number of start-ups grows by 81%, while respective costs increase by 119% in this period. Related to variable renewables’ production, start-up costs increase by a mere €0.70 per additional megawatt hour. While the expansion of variable renewables alone would increase start-up costs, more flexible biomass power plants and additional power storage have counteracting effects. Yet changes in reserve provision and fuel prices increase start-up costs again. The relevance of start-up costs may grow further under continued renewable expansion, but could be mitigated by increasing system flexibility.