Modeling Large Electric Vehicle Fleets in Power System Simulations

The need to reduce total greenhouse gas emissions leads to an increase in suitable efforts in all sectors. Therefore, in the transportation sector, a growing number of electric vehicles is expected. A rising number of electric vehicles also increases the electric load, which in turn increases demand on electricity markets. Depending on the time of charging processes, higher peak loads and a rising demand for flexibility could be the consequence. At the same time, electric vehicles and the possibility to shift their charging processes could counter this rising demand for flexibility or even enable the vehicles to provide flexibility for the grid. In order to study problems like this, market simulations are frequently used. In that context or for other types of power system simulations, adequate modeling of electric vehicles becomes indispensable. Therefore, firstly, this paper discusses implications of modeling large numbers of individual electric vehicles in power system simulations. Subsequently, we propose a way to model aggregated vehicle classes to circumvent possible problems adequately considering relevant restrictions. We use exemplary investigations in a market simulation to validate our model. The results indicate that the proposed model is suitable to represent large fleets of electric vehicles in power system simulations.