Article Series Dynamic inductive charging in traffic: Technology Acceptance of Dynamic Inductive Charging Infrastructure in Public Transport

In recent years, several research projects have been conducted to explore the practical implementation of dynamic inductive charging (Dynamic Wireless Power Transfer – DWPT) in electric vehicle charging. This innovative technology enables wireless energy transfer, charging electric vehicles while in motion. But how exactly does this technology work, and where do we encounter induction and inductive charging daily? What potential does dynamic inductive charging hold for public transportation, and what are its implications for the environment, humans, and energy system? This article series addresses these and other questions and looks at dynamic inductive charging from various perspectives.

The third article in this series focuses on the public acceptance of the DWPT technology. As part of the “ELINA” research project, a passenger survey on the acceptance of DWPT was conducted. This survey took place during the garden exhibition in Balingen, where a bus with DWPT technology was used on public roads for the first time in Germany. During the survey, the bus was a shuttle for garden exhibition visitors. The bus was charged via DWPT on a 400m stretch in the city center and statically inductively charged at two stops. Passengers could follow the charging process via a display in the bus, gaining first impressions of the charging technology and its functionality on-site.

Background and Objectives of the Survey

Throughout the garden exhibition, shuttle bus passengers were invited to participate in the survey via notices on the bus (see Figure 1) and by staff on-site—the study aimed to gain an initial impression of the acceptance of this innovative charging technology. The study identifies relevant factors influencing acceptance to derive the socially pertinent framework conditions for market diffusion. Since Balingen has the first pilot route of this kind in Germany, few people currently have experience with DWPT technology in traffic. The advantage of the survey in Balingen is that passengers could already gain initial experiences and impressions before participating, allowing for a different quality of responses. The survey, lasting about eight minutes, was designed to be feasible within the shuttle ride time.

In the ELINA project, this passenger survey is used as a first reference point to conduct a nationwide representative survey on the acceptance of DWPT technology for electric vehicles.

Methodology: Online Survey Among Passengers

A quantitative cross-sectional study was conducted using an online survey to assess the extent of technology acceptance and relevant influencing factors. It included five demographic and 13 content-related questions. By surveying passengers in the inductively charged shuttle bus, the survey’s target group consists of people with initial experiences of dynamic inductive charging technology. The survey took place from 7 June to 25 September 2023.

Results

Sample: A valid sample of 158 responses was achieved. The average processing time was approximately 6.5 minutes, within the specified duration of eight minutes.

Demographics: The majority of participants were older than 40 years. Men slightly outnumbered women, making up 56% of the sample. Nearly 60% of respondents were employed, while almost 30% were retired.

Findings:

• More than two-thirds of respondents desire battery-electric propulsion for city buses.
• 95% of respondents rated dynamic inductive charging of city buses positively.
• Over half of the respondents were completely fine with installing dynamic inductive charging coils, and about one-third found it somewhat acceptable.

95% of respondents had a positive view of dynamic inductive charging for city buses. Additionally, 85% supported the installation of dynamic inductive charging coils in public streets. Only 13% of respondents saw a safety risk in contactless energy transfer via an electromagnetic field. Concerns about visual disruption from control cabinets on sidewalks and noise pollution were negligible (<6%).

Figure 2 provides further insights into the respondents’ answers. The subjective assessment of the general knowledge level about dynamic inductive charging technology was higher than expected within the project, at 50%. The strong support for this charging technology is also reflected in the high approval (86%) of respondents who want to use dynamically inductively charged electric buses daily. About one-third wanted information on whether the vehicle is dynamically inductively charged, while half of the respondents did not find this information relevant. A higher proportion of respondents (44%) showed interest in clearly visible markings of areas for dynamic inductive charging. Recommendations for integrating the charging technology into public spaces can be derived from this.

Another point of interest was identifying the key factors influencing technology acceptance. Given the limited scope of the survey, participants were asked about the potential advantages and disadvantages of dynamically inductively charged buses. Participants could provide these via free text, with 40 participants listing advantages and 19 listing concerns. The responses were then thematically clustered and sorted by the frequency of occurrence.

Potential advantages mentioned:

• Promotion of an environmentally friendly drive (35%)
• No long charging breaks (20%)
• Innovative technology (18%)
• Increased range (15%)
• Potential to reduce battery capacity (10%)
• More convenient than cable-based charging (10%)

Potential concerns mentioned:

• Battery disposal (21%)
• High investment costs (21%)
• Environmental impact of the magnetic field (21%)
• System efficiency (16%)
• Environmental impact of production (11%)
• Reliability (11%)

Conclusion and Outlook

The survey results indicate a positive attitude towards dynamic inductive charging of city buses among the study participants. Additionally, there was a desire for information about the use of DWPT technology, particularly for visible markings of areas for dynamic inductive charging. More potential advantages than concerns were expressed, underscoring the positive evaluation of the technology. The expressed concerns can provide insights into further information needs and acceptance criteria for implementing the technology.

This survey serves as a basis for the ELINA project to conduct a planned nationwide representative study on the acceptance of dynamically inductively charged electric vehicles. The insights gained from the passenger survey help contextualize previous findings from the literature and provide a framework for further surveys.