Supercharging the resilience of the EV ecosystem

July 2024 | Highlights Community

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Uncovering the impact of urban flooding on the accessibility of EV chargers paves the way for mitigation strategies that help policymakers strengthen the resilience of charging infrastructures.

The motors of the electric vehicle (EV) sector are spinning at full throttle — with the goal of eventually phasing out internal combustion engines that guzzle fossil fuels and emit planet-cooking gases. But the very lifeline that keeps the sector moving forward — its charging infrastructure — is beginning to experience significant strain.

This strain could adversely impact the perceived availability and accessibility of charging stations, which in turn fuels range anxiety and dampens EV adoption. It is also crucial that the chargers are resistant to external factors, such as weather-related events.

Researchers from the College of Design and Engineering at the National University of Singapore have studied the impact of urban flooding on public EV charging networks, focusing on Greater London. Their research zooms in on how climate-induced flooding affects these networks, revealing significant stress and accessibility challenges for chargers during such events.

Their insights shine a crucial light on resilient infrastructure planning, offering strategic guidance for the private sector and policymakers alike in enhancing the flood resilience of urban EV charging networks. Led by Associate Professor Jimmy Chih-Hsien Peng from the Department of Electrical and Computer Engineering, the team’s findings were published in Nature Communications on 09 June 2022.

Associate Professor Jimmy Chih-Hsien Peng’s research guides the deployment of resilient urban EV charging networks.

Going the extra mile

From New York to London to Singapore, urban flooding — increasingly frequent and severe due to climate change — has exposed charging infrastructure to the elements.

Floods pose risks to EV charging stations in two main ways. Firstly, individual chargers may go out of service due to water damage. On the other hand, even if chargers are weatherised or elevated, they can still become unusable if the surrounding parking areas are waterlogged.

The team’s research addresses a gap in existing literature, providing insights into disruptions that may occur if a significant number of chargers in a network are compromised by flooding.

Through computer simulations, fed with publicly available data on vehicle driving habits, the research team analysed changes in charging patterns during flooding events in Greater London. They also evaluated methods to enhance the resilience of the charging infrastructure.

"What is surprising is that this impact extends beyond the immediate flood areas, affecting regions up over 10 kilometres away as EV users are forced to postpone their charging."

“Greater London provided a particularly informative case study for several reasons,” explains Assoc Prof Peng. “The region has a significant share in the UK’s EV market, accounting for about a seventh of all sales, and is on a path to shift entirely to EVs by 2030. Moreover, a considerable area of Greater London is prone to flooding — many boroughs and key development areas are at high risk. This, combined with the fact that over 40% of drivers in the area depend on public or on-street parking — areas most vulnerable to such events — made it a compelling focus for our research into the resilience of charging infrastructure.”

The team discovered that while flooding does not impede typical urban travel for EV drivers, it substantially stresses and limits access to parts of the charging network. “What is surprising is that this impact extends beyond the immediate flood areas, affecting regions up over 10 kilometres away as EV users are forced to postpone their charging,” says Gururaghav Raman, a Research Fellow and a former PhD student at NUS, who is also the first author of the study.

"What is surprising is that this impact extends beyond the immediate flood areas, affecting regions up over 10 kilometres away as EV users are forced to postpone their charging."

“These findings highlight the need for placing new chargers strategically, particularly in areas less prone to flooding, to alleviate the pressure on existing networks,” adds Raman.

Building future-proof charging infrastructure

The researchers have proposed four strategies for deploying new chargers. The first involves placing additional chargers just outside flood-affected areas — effectively ring-fencing these regions to destress nearby infrastructure. The second strategy is usage-dependent, where chargers are placed in areas with the highest baseline utilisation. The third, a distance-based approach, plants chargers near the most affected locations far from flood zones to reduce peak stresses. The final strategy involves randomly distributing new chargers throughout the network.

Through simulations, the team put their strategies to the test. Results have shown that the usage-dependent strategy excels in enhancing flood resilience, accessibility and efficiency of the charging network. In particular, just adding 5–10% more chargers could restore peak utilisation to baseline levels during floods. The researchers also point out that this strategy aligns with the competitive nature of the private sector, which installs most new public chargers.

Additionally, the researchers also highlighted the effectiveness of ring-fencing vulnerable areas around the Thames with additional chargers — irrespective of baseline demand — to reduce stress and improve accessibility. On the other hand, randomly placing chargers has its benefits too. “While these two strategies are not immediately profitable, government subsidies can play a crucial role in catalysing the installation of chargers in these areas, which bolsters accessibility and supercharges consumer confidence,” adds Raman.

“Augmenting these strategies depends on the availability of more detailed city-specific data,” says Assoc Prof Peng, who is actively involved in planning and formulating industry standards. “For instance, if furnished with information on installation costs, revenue and flood risk, policymakers could employ multi-criteria optimisation methods to better determine the most effective locations for new chargers — catering to the unique needs and challenges of each city.”