Carbon and energy prices under uncertainty: A theoretical analysis of fuel switching with non-equally efficient power plants

European power producers have a major influence on the EU ETS, given that both their CO2 emissions and their EUA (European Union Allowance) allocations account for more than half of the total volumes of the scheme. Fuel switching is often considered as the main short-term abatement measure under the EU ETS. It consists in substituting combined cycle gas turbines (CCGTs) for hard-coal plants in power generation. Thereby coal plants run for shorter periods, and CO2 emissions are reduced. This paper provides a theoretical analysis of fuel switching, in a context where power plants involved are not equally efficient. We begin with some analyses which enable us to observe how differences in the efficiency of power plants impact the cost of fuel switching, and how this is related to the level of switching effort. Based on these preliminary analyses, we build the first partial equilibrium model taking into account the effect of differences in the efficiency of power plants involved in fuel switching. We also investigate the effect of the timing of fuel switching abatements, within the temporally defined environment of our dynamic partial equilibrium model. Results show that the gas price, uncontrolled CO2 emissions and the timing of abatement (through the time of occurrence of random shocks on uncontrolled emissions) act together on the carbon price, and on its relationship with fuel prices..