Assessing electric vehicle CO2 emissions in the Portuguese power system using a marginal generation approach

In this work the electric vehicle (EV) specific CO2 emissions resulting from the EV integration on the Portuguese power system are analyzed, considering a large set of scenarios combining the system renewable capacity versus EV share, under a night charge scenario. For this purpose, a unit commitment and economic dispatch (UCED) is applied to the power units scheduling. The optimization procedure is implemented in General Algebraic Modeling System (GAMS) and performs the dispatch of the thermal and hydro units, in order to minimize the operation costs. The model is applied to an entire year of operation in a hourly basis using a marginal methodology. According to the results obtained, for the scenarios considered, the EV specific CO2 emissions range from 57 g CO2/km, for high wind capacity and low EV penetration, to 129 g CO2/km, for low wind capacity and low EV penetration. From the results, it can be concluded that, with the current wind capacity of the Portuguese system, the impact of the EV in terms of CO2 emissions is not beneficial when compared to the 95 g CO2/km target, for penetrations lower than 1 million vehicles. Results also show that EVs can be integrated in an environmental beneficial way, if increasing EV penetrations are combined with an increase in the installed wind capacity.