LAUSR

Abstract With the phase-out of coal power plants, the existing mix of instruments aimed at decarbonising electricity sectors is getting more complex. This paper contributes to its understanding by highlighting the impact of coal phase-out, CO2-price and increasing capacity of variable renewable energies on contribution margins of power plants. By visualizing these three instruments in a brownfield screening curves model (SCM), their fundamental effects on plant operation, electricity price and margins become apparent at a glance. Moreover, the SCM allows to derive generic statements about winners and losers on the supply side. Results are then quantified within a case study for Germany using the power sector model E2M2. The high resolution regarding time and generation system permits a realistic simulation of electricity prices and thus of margins at plant level. We conclude that 1) margins between technologies and plants within the same technology vary significantly, in extreme cases by 9.5 times (period 2020–2050). And 2) the impact of a coal phase-out declines when the other two policies become more stringent. E.g. for an old lignite plant, a coal phase-out in a moderate political environment causes a loss in margin of 47%, whereas the loss is only 16% in an ambitious environment.