Integrating carbon intensity in electric vehicle charging at office parking lots

The Dutch electric vehicle (EV) fleet is growing rapidly, which comes with challenges regarding the coordination of charging in locations like office parking lots. As the transition to EVs is at least partially motivated by sustainability goals, this work considers not only the omnipresent objective to flatten the aggregated power profile behind the transformer, but also to reduce (time-of-use) carbon emissions associated with the power drawn from the grid. Concretely, this paper presents results of a simulation study for a scenario with 400 EVs based on a real-world office parking lot. The analysis focuses on the impact of using flattening or carbon objectives for the coordination of EV charging, as well as the potential of optimizing for a weighted combination of both objectives. The findings clearly illustrate the trade-offs between flattening and carbon-minimization. While naively minimizing time-of-use carbon emissions may result in an increase of peak power drawn from the grid, assigning some weight to the flattening objective reduces the magnitude of peaks and allows to implicitly scale peaks to comply with the size of the available grid connection.