A new study has delved into the future of ultrafast EV charging stations in China, exploring charging patterns, grid impacts, solutions, and upgrade costs.
The research team, led by Yang Zhao, Xinyu Chen, and Michael McElroy, analysed real-world charging data from over 15,000 EVs at ultrafast EV charging stations across ten districts in Beijing.
They established scenarios for current and future EV specifications and charging parameters, considering factors such as charging power, battery energy, and charging times.
As the global EV market continues to expand rapidly, with China leading the way in EV adoption, understanding the impact of ultrafast EV charging is crucial for sustainable development.
The impacts of ultrafast EV charging on power capacity
One of the key findings is related to the impact of increased ultrafast EV charging power on station loads.
Contrary to the common assumption that doubling charging power would double the station load, the study shows that this is not the case. Larger stations with more chargers experience a relatively modest peak power increase of less than 30% when fast-charging power is doubled.
This is because shorter charging sessions are less likely to overlap. For example, in the simulations, as the maximum EV charging power increased tenfold from scenarios S1 to S7, the peak load at the airport charging station increased by only a factor of 4.90.
Exploring solutions to preserve power
The researchers also investigated two generalised solutions to address the issue of insufficient power capacity at ultrafast EV charging stations: a dynamic waiting strategy and the deployment of energy storage. The dynamic waiting strategy can effectively decrease peak loads by delaying some charging sessions.
For instance, at the airport, the EV charging station, with a total power capacity of 120 kW times the number of chargers, can satisfy ultrafast charging demands from S1 to S7 using only this strategy, with a reasonable increase in waiting times.
Regarding energy storage, it can buffer peak loads, but the cost is a major consideration. The unit cost of lithium-ion battery energy storage is approximately four times higher than that of pad-mounted distribution transformers in China.
However, energy storage has its advantages, such as not requiring grid capacity expansion and enabling more flexible installation.
Analysing the expenses of ultrafast charging stations
When it comes to upgrade costs, the study identified chargers and distribution transformers as the main expenses.
Comparing different upgrade strategies, the research provides valuable insights for policymakers and industry players.
The results suggest that deploying large ultrafast charging stations with chargers between 350–550 kW in high-demand regions could be a viable solution to meet the surging charging demands of EVs in China.
This research offers a comprehensive understanding of the future of EV ultrafast charging stations in China, which will contribute to more informed decision-making in charging infrastructure planning and grid management.
