It is looking increasing likely that electric vehicles will play a major role in the future of road transport. While commercial electric vehicles exist their uptake has been limited due to high purchase costs, limited battery range, and a lack of charging convenience. Furthermore, while developments are underway, electric and hybrid drive trains are yet to be efficiently integrated with heavy goods vehicles (HGVs). A novel way to overcome such challenges are Electric Road Systems; a branch of technologies that allow vehicles to charge while in motion. Limited information exists regarding the comparative performance of ERS solutions, market readiness, costs, and implementation issues. To this end, the World Road Association (PIARC) commissioned TRL to undertake a state-of-the-art review and feasibility study of ERS concepts; focusing on ERS implementation from the perspective of a road administration.

The study had three interlinked phases:

1. state-of-the-art review and stakeholder engagement,
2. technological and implementation feasibility assessment, and
3. exploring the business model for ERS uptake.

A review of stationary charging and other alternatives to fossil fuel propulsion technologies was also undertaken. The study adopted a global perspective, engaging with key stakeholder (road administrations, researchers, ERS developers, freight industry) from countries across the economic spectrum through an online survey and interviews with relevant experts. This informed the review, highlighting stakeholder views on benefits, limitations and barriers to development/implementation. A total of 17 viable ERS systems were identified. These are split into three categories: inductive (wireless); conductive rail; and conductive overhead. The majority of inductive ERS have a technology readiness level (TRL) between TRL3-4; with few systems advancing beyond TRL6. Conductive counterparts are more mature, typically between TRL4-5, with some systems between TRL6-8. All three types of ERS are undergoing road trials of some form, with rapid advancements in the last 5 years.

All three concepts are technologically feasible, providing comparable and unique advantages/limitations. For instance, conductive systems are more able and ready to support the power requirements of heavy goods vehicles. Whereas inductive ERS are generally more suited to vehicles with lower power requirements and cannot deliver at efficiencies equal to conductive systems. Risk assessments of each technology were undertaken, with results suggesting the majority of risks are'low to very low'. Conductive rail solutions however were inherently more risky due to: the presence of an open live conductor on high speed roads; and their impact on road maintenance activities. Concerns arise over the impact of any type of system that is integrated into the pavement structure, regarding durability, future maintenance and safety. Interoperability, within and across ERS categories does not currently exist.

Stakeholder engagement results suggest that despite uncertainties regarding ERS performance and barriers to implementation, the majority viewed the technologies positively and believed that ERS would be key to decarbonising road transport. Approximately half of the survey participants were actively involved in ERS research (from desktop studies to road trials). The majority of research is being undertaken in Europe, South Korea, Japan and the USA. Discussions with road administrations and developers emphasised that different ERS concepts should be viewed as solutions for given scenarios, rather than as'rivals'. Instead, the overall aim of all solutions is to better improve the sustainability of road transport networks and mitigate current levels of environmental impact. Stakeholders identified freight industry and public transport operators to be the likely first adopters of ERS. Stakeholders identified the key barriers to implementation as being high capital cost (for installation, maintenance and administration), alongside the risks associated with relatively immature technology. A key message from stakeholders was that government support is critical to ERS development and in addressing industry concerns.

As part of the study, a workshop was held, with relevant experts, to discuss potential implementation challenges of ERS in Low and Middle Income Countries (LMIC). Regarding installation, the following challenges were identified: existing infrastructure construction type, fleet composition, lack/availability of skills and resources, and limited grid infrastructure and capacity. However, LMIC have some unique opportunities, such as combining the construction of both new roads and grid infrastructure with ERS installations. The overall consensus from the workshop was that ERS would have to be established first in high income countries before it could be realistically considered for implementation in LMIC. Also, given the high capital costs associated with ERS and the many other priorities in LMIC that require investment and support, ERS is not likely to be installed in the near future. It may be possible in the long term that ERS could be installed on transnational freight routes if external funding was made available.

The bulk of current research is focused on functionality and installation. However other aspects required further attention, such as economic viability and the development of attractive business models. The study presents a UK specific cost-benefit analysis for a case study motorway. Assumptions, based on Phase 1 and 2 findings, were made on installation prices, technology take-up, and vehicles types suitable for ERS concepts. The results suggested that some types of ERS could be economically viable with sufficient electricity mark-up and technology penetration. However, there needs to be a clear understanding of who the main customer basis is. The ERS concept type affects the potential market, as the conductive overhead system can only be used by taller vehicles such as HGVs and buses, whilst in-road systems could be used by both light vehicles and HGVs. However, for light vehicles, ERS would be competing with other charging solutions; it is likely that private EV owners will use mainly plug-in or static charging solutions. Advances in other low carbon technologies, such as bio-fuels, fuel-cells, and electric batteries may also influence the take-up of ERS. As yet there is no clear evidence to suggest that it would either promote or limit ERS implementation. With respect to delivery, it is still unclear as to where the responsibility for ownership and operation of ERS technology should fall. It seems most likely that some form of private public partnership would be needed for implementation. This will require modifications to the existing regulatory framework and concessions between road administrations and operating contractors.

Overall the study concluded that ERS has the potential to play a major role in the decarbonisation of road transport, but in the short term is most likely to be adapted by specific parties to meet localised needs rather than a universal solution.

Recommendations for road administrations are provided in two stages:

1. intermediate steps for ERS implementation which include: identifying potential routes for ERS implementation; identifying relevant standards and policy that require modification in order to plan future integration; to participate in international forums and technical committees; and to share knowledge with international road administrations and research organisations;
2. long term objective should be to support and take part in road trials that aim to better understand the benefits and impacts of ERS for a given transport network.

NRAs in LMIC should continue to monitor developments in ERS; engage in international discussions; identify country specific challenges; and consider ERS solutions in future green-fund opportunities, particularly for new road construction and on international freight corridors. It was also suggested that PIARC could support its members by seeking opportunities to partner with other key stakeholders and co-hosting an international conference on ERS development; establishing an alternative fuel task force in the next work cycle; and representing road administrations in global discussions on ERS.