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

Abstract

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.