Flexible Charging of Electric Vehicles: Results of a Large-Scale Smart Charging Demonstration

Pieter C Bons,Frank Geerts,Robert Van Den Hoed,Aymeric Buatois,Friso Schuring

doi:10.3390/wevj12020082

Pieter C Bons, Frank Geerts + Show 3 more

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https://doi.org/10.3390/wevj12020082

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Abstract

Flexible charging can be applied to avoid peak loads on the electricity grid by curbing demand of electric vehicle chargers as well as matching charging power with availability of sustainable energy. This paper presents results of a large-scale demonstration project “Flexpower” where time-dependent charging profiles are applied to 432 public charging stations in the city of Amsterdam between November 2019 and March 2020. The charging current on Flexpower stations is reduced during household peak consumption hours (18:00–21:00), increased during the night-time, and dynamically linked to solar intensity levels during the day. The results show that the EV contribution to the grid peak load can be reduced by 1.2 kW per charging station with very limited user impact. The increased charging current during sunny conditions does not lead to a significantly higher energy transfer during the day because of lack of demand and technical limitations in the vehicles. A simulation model is presented based on empirical power measurements over a wide range of conditions combining the flexibility provided by simulations with the power of real-world data. The model was validated by comparing aggregated results to actual measurements and was used to evaluate the impact of different smart charging profiles in the Amsterdam context.

Highlights

Electric vehicles (EVs) are no longer only a niche market and will increasingly define passenger mobility with a market growth of over 30% for the last five years and an accumulated amount of 5 million EVs on the roads in 2019 [1]
We present and discuss the impact the Flexpower profile has on the EV charging process
Results are presented on (i) charging power per active session, (ii) charging power per station, (iii) positively/negatively affected sessions on Flexpower charging stations compared to the reference stations, (iv) the effect of dynamic current levels linked to solar intensity, and (v) results of a simulation using measurements of real-world transactions as input

Summary

Introduction

Electric vehicles (EVs) are no longer only a niche market and will increasingly define passenger mobility with a market growth of over 30% for the last five years and an accumulated amount of 5 million EVs on the roads in 2019 [1]. The electrification of transport and the need for more and faster charging is expected to add a considerable load on the electricity infrastructure in the near future [2]. Because the timing of the peak in demand of EV charging coincides largely with the peak in household consumption, the total peak load will increase directly with the addition of more EVs and the limits of the grid capacity may be reached [3,4,5]. The required expansion of charging stations will increase the load on the local electricity grid. Smart charging of EVs offers opportunities for better managing and incorporating this additional electricity demand within the boundaries of the existing grid

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