A new study has examined the future of ultrafast electric vehicle charging stations in China, examining how they affect the power grid, charging habits, possible solutions, and upgrade costs.
In China, EV fast-charging power in China has quadrupled over the past five years, moving toward 10-minute ultrafast charging. This has raised concerns over increased strain on the power grid.
For this research the team analysed charging data from over 15,000 EVs using fast-charging stations in Beijing. They looked at both current and future EV charging needs, including battery sizes, charging speeds, and how long vehicles stay at charging stations. Their results have been published in a paper: ‘Future Ultrafast Charging Stations for Electric Vehicles in China: Charging Patterns, Grid Impacts and Solutions, and Upgrade Costs.’
One key finding contradicted the common assumption that increasing charging power will cause a direct, equal increase in power demand at stations. The researchers actually found that large stations – those with 12 or more chargers – saw less than a 30% rise in peak power when charging speed doubled, due to shorter sessions which overlap less. Even when EV charging power was increased tenfold in simulations, the busiest station – located at the airport – only saw its peak power demand rise by about five times.
To help stations handle peak demand without overloading the grid, the study tested two main solutions: a ‘dynamic waiting’ strategy and energy storage. The dynamic waiting approach slightly delays some charging sessions to reduce pressure on the system. At the airport station, this method alone was enough to meet even the highest charging demand scenarios, though it meant longer waiting times.
Energy storage such as battery systems can also help but the cost is high. Lithium-ion storage in China costs about four times more than traditional grid upgrades using distribution transformers, although storage systems offer benefits like quicker setup and less need for major grid changes. The study also examined upgrade costs, highlighting that chargers and transformers make up the bulk of expenses.
The research concludes: ‘To meet surging charging demands of EVs in China and further support the transition to sustainable transportation, it is essential to consider deploying ultrafast charging stations in high-demand regions. This initiative will enhance charging convenience for EV users with limited home charging options and/or in populous regions.
‘Based on the results in this work and the fact that current advanced charging technology has exceeded half a megawatt, we recommend deploying large ultrafast charging stations with chargers between 350 to 550 kW in high-demand regions immediately.’
The full research can be read here.
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