Simultaneity Factors of Public Electric Vehicle Charging Stations Based on Real-World Occupation Data

Abstract

Charging of electric vehicles may cause stress on the electricity grid. Grid planners need clarity regarding likely grid loading when creating extensions. In this paper, we analyse the simultaneity factor (SF) or peak power of public electric vehicle charging stations with different recharging strategies. This contribution is the first of its kind in terms of data quantity and, therefore, representativeness. We found that the choice of charging strategy had a massive impact on the electricity grid. The current “naive” charging strategy of plugging in at full power and recharging until the battery is full cause limited stress. Price-optimised recharging strategies, in turn, create high power peaks. The SFs varied by strategy, particularly when using several connectors at once. Compared to the SF of a single connector in naive charging, the SF decreased by approximately 50% for groups of 10 connectors. For a set of 1000 connectors, the SF was between 10% and 20%. Price-optimised strategies showed a much slower decay where, in some cases, groups of 10 connectors still had an SF of 100%. For sets of 1000 connectors, the SF of price-optimised strategies was twice that of the naive strategy. Overall, we found that price optimisation did not reduce electricity purchase costs by much, especially compared to peak-related network expansion costs.

Maximum Tolerated Number of Simultaneous BEV Charging Events in a Typical Low-Voltage Grid for Urban Residential Area

“…The influence of EV charging on the electrical grid has been the subject of many research studies from around the world [4][5][6][7][8], and multiple strategies have been proposed to minimize its negative impacts [9][10][11][12]. Similarly, several studies in this field have recently been undertaken using real or typical German LV grids, as highlighted in [13][14][15][16][17][18].…”

“…Gemassmer et al [14] examined the impacts of three different charging methods on the voltage and line/transformer loadings of LV grids for urban and rural regions in Berlin and Brandenburg; simulations were carried out with 0.1% of the anticipated number of vehicles in 2040. Hecht et al [15] analyzed SF, peak power, CO 2 intensity, and electricity prices under four different charging methods using real data from public charging stations in Germany. However, the other challenges in the LV grid, such as voltage stability and line/transformer loadings, have not been studied.…”