Study explores EV lane charging potential
The impact of wireless electric vehicle (EV) charging stations on a section of the Auckland motorway, including economic feasibility, length of charging lanes, traffic effects and energy consumption , is examined in a recent study.
Dynamic Wireless Charging (DWC) stations are integrated into the road and use electromagnetic induction to charge electric vehicles as they move, says Business School researcher Dr Selena Sheng.
“This offers a viable solution to alleviating issues associated with EV use, including range anxiety and charging times.”
Ramesh Majhi, PhD Candidate in Engineering, Dr Prakash Ranjitkar, Senior Lecturer in the Faculty of Engineering, and Dr Sheng have developed a traffic simulation framework and a ‘load state’ model to assess the impacts of DWC installations using a 90 km section of State Highway 1.
Their work, published in the international journal Sustainable Cities and Societies, titled Assessment of dynamic wireless Charging based electric road system: A case study of Auckland highway, used various scenarios and measurements, including four different inductive power transfer capacities (50, 75, 100, and 125 kilowatts), live traffic data and two types of traffic conditions – peak hour and free flow, to evaluate the performance of dynamic wireless charging systems.
The study demonstrates that with an increase in the inductive power transfer capacity, the total energy demand and the length of the required load section decreases. As the supply capacity of a wireless charging station increases from 50 kilowatts to 125 kilowatts, the cumulative length of the charging sections required along the 90 km corridor decreases from 34% to 12%, depending on the study.
With increasing demand for charging, on-road wireless installation will soon become more competitive than current plug-in charging stations due to cost savings associated with travel time, delays and charging time.
Meanwhile, although the paper does not explore the total cost associated with the implementation of DWC in the transport network, the researchers investigated the economic feasibility of the wireless system in terms of the total cost associated with a section of State Highway 1 by comparing it to the cost associated with using plug-in charging stations within 1 km of the highway corridor.
“We found that the total capital cost of a DWC installation in the corridor for a system with an inductive power transfer capacity of 50 kilowatts is $1.59 million per year when traffic is flowing freely, compared to $1.42 million per year for peak hour traffic. ”
The cost variation, says lead author Ramesh Majhi, is due to faster speeds when traffic moves freely; therefore, a longer charge length is required to satisfy the demand.
Without considering the time it would take to get to a static charging station, a wireless charging path would only be cheaper at 125 kilowatts and above, according to the article.
However, when comparing the feasibility of the two charging facilities in terms of total cost, the researchers say it is imperative to consider the value of time (travel time, delay and charging time), which is significantly higher for plug-in charging stations than for wireless charging on the road.
At higher inductive power transfer capability, such as 75 kilowatts and above, on-road wireless charging installation becomes less expensive compared to the typical plug-in configuration under peak hour conditions while accounting for the travel time cost.
As the EV population grows, time costs tend to become greater for using plug-in charging stations, which will make dynamic wireless charging more feasible and competitive in the future, the researchers say.
“As the existing plug-in stations can only handle limited electric vehicles at any given time, with the increase in charging demand, the on-road wireless installation will soon become more competitive with the current plug-in charging stations due to cost savings associated with travel time, delays and charging time,” says Majhi.
“In addition, thanks to the advanced research on dynamic wireless charging system components, the cost of building a wireless charging lane will soon decrease, making it more feasible than the existing plug-in charging.”