transport 27-30

27-30

2020

Proceedings of 8th Transport Research Arena TRA 2020, April 27-30, 2020, Helsinki, Finland

Electric road system technologies in Sweden Gaining experience from research and demo facilities

Magnus Lindgren

aSwedish Transport Administration, SE-781 89 Borlange, Sweden

Abstract

Electric Road System (ERS) is a technology concept that has the potential to heavily reduce the fossil fuel dependency in the transport system. ERS is defined by electric power transfer from the road to the vehicle while the vehicle is in motion through rail, overhead-line, and wireless solutions. The basic technologies for power transfer from the road to vehicles in motion have been developed through various research projects across the globe. However, electric road systems had never been demonstrated for heavy-duty vehicles on the public road until the Swedish pre-commercial procurement. The first ERS in the world was inaugurated in 2016 and since then significant amounts of experience regarding building, operating and maintaining ERS has been gathered. The main conclusion is that ERS works, it is possible to transfer electric energy from the road to a vehicle in motion.

However, additional verification is needed before any ERS is fully mature.

Keywords: Low emission transport, Electric road system, Sustainability, Demonstration, Infrastructure, Electrification

Nomenclature

ERS Electric road systems TRL Technology readiness level CO2 Carbon dioxide

1. Introduction

The Paris Agreement have highlighted the need and global ambitions to undertake ambitious efforts to mitigate climate change. In Sweden, the Government have ratified the convention and formulated national goals. Sweden will be one of the world’s first fossil free welfare states, and by 2045 Sweden shall have zero net carbon dioxide emissions. For the transport sector, the Government have developed specific goals to reduce the carbon dioxide emissions, by at least 70 percent in 2030 compared with 2010.

The national transport sector (road, rail and domestic maritime and aviation) are responsible for approximately 17 million tonnes of CO2-equivalent per year, as reported by the Swedish environmental protection agency (2018).

The road transport sector is dominating this with approximately 94 percent of the emission from the transport sector, or approximately 1/3 of the national CO2 emissions. Several studies, as mentioned in Swedish transport administration (2016), have been undertaken regarding possible measures to reduce the fossil dependency, and reduce the climate effect from the transport sector. These measures can be divided into:

• Energy efficient vehicles, vessels and crafts,

• Energy efficient use, e.g. Eco driving and logistics,

• Renewable and sustainable energy including electricity,

• Intermodality, and

• Transport efficient society planning

The energy efficiency improvement within the light duty vehicles (passenger cars) sector have been significant over the last years. Since 2005, the average CO2 emission from passenger cars, new registrations, have been reduced by almost 30 percent. Since the introduction of the sales-weighted average CO2 emission regulation in 2008, emissions have fallen by more than 3 percent per year according to ICCT (2017). The main solutions towards fossil independency are energy efficiency of conventional vehicles and electrification.

For heavy-duty vehicles, we have not seen the same level of improvements, and only a few countries have introduced CO2 regulations up to date. Electric Road System (ERS) is a technology concept that has the potential to heavily reduce the fossil fuel dependency in the transport system. ERS is defined by electric power transfer from the road to the vehicle while the vehicle is in motion, and could be achieved through different power transfer technologies from the road to the vehicle, such as rail, overhead-line, and wireless solutions. The basic technologies for power transfer from the road to vehicles in motion have been developed through various research projects across the globe. Two ERS projects are being tested on public roads in Sweden and two more are planning for to start their demonstration activities during late 2019 or 2020. Besides the Swedish demonstration facilities, one test was started in Los Angeles, USA in 2017, and three large demonstrations have been started or are planned for in Germany in 2019. This paper will focus on the activities in Sweden.

2. National roadmap for electric road system

The Swedish Transport Administration (2017) have received a governmental assignment to investigate and report the conditions for whether electric road systems may be part of the state owned road network. The assignment includes the following steps;

• Costs, tax/fee models, financing models and taking into account the current funding principles for state transport infrastructure

• Environmental and climate impact in a lifecycle perspective including impact on landscapes as well as valuable natural and cultural environments

• Need for changes in regulations

• Spread of technology, as well as

• Impact on the ability to achieve the transport policy objectives

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2.1. Pre-commercial procurement

The Swedish Transport Administration used pre-commercial procurement to gain knowledge about ERS, especially relating to construct, maintain and operate ERS on a public road infrastructure. Pre-commercial procurement can be used by an authority to address a presumptive marked need at an early stage of development.

If deployed when the market is too immature or too developed there is a high risk that the pre-commercial procurement will fail. For this specific procurement the Swedish Transport Administration used the technology readiness level (TRL) scale as presented by the European Union (2014) to define the maturity of the various ERS technologies and market in general. The area of focus were ERS technologies between TRL 4 and 7.

Based on a preparatory dialogue with the market in 2011-2013 it was concluded that the timing was appropriate.

When the pre-commercial procurement was launched in 2013, the Swedish Transport Administration received offers from 11 different consortia. Another indication of the appropriate timing, is that ERS demonstration activities in other parts of the world have been announced or started. For example the Port of LA in the USA, three different test sites in Germany, and in northern Italy.

One important criteria for the procurement was the technology neutrality, all ERS technologies were included independent of the energy coming from above, from the side or underneath the vehicle. Both conductive and inductive solutions where included. The pre-commercial procurement was divided into 4 different phases with an evaluation between each individual phase. The requirement and level of detail rose for each phase and the number of remaining consortia decreased, as an effect of the evaluation. At the end only two consortia or projects remained.

2.2. Existing demo sites

Today the Swedish Transport Administration have successfully procured, through the pre-commercial procurement, four projects leading up to four individual demonstration facilities for electric road systems. The location and ERS technologies vary between each test site:

• Overhead lines in Sandviken

• Road-bound electric rail in Arlanda

• Road-bound electric rail in Lund

• Inductive system in Visby

The two first projects were started in 2015, and the experience gained from these are the focus of this paper. The two last projects were started in 201, and the available experience is therefore limited.

2.2.1. Overhead lines in Sandviken

As reported by Region Gävleborg (2018a) the Sandviken ERS is based on overhead lines and was the first electric road in the world, for heavy duty trucks on public roads, when it was inaugurated the 22 June 2016. The technology is based on the same principle that have been used for the electrified railway network. In this demo, Siemens is the ERS technology supplier. Siemens have a long experience with electro mobility, both within the railway and road transport sector. One of the first electric road transport system was, according to Siemens (2019), supplied by Siemens in 1882 and based on an open carriage without horses or rails (i.e. a trolley bus) in Berlin, Germany.

The ERS in Sandviken consist of a double overhead line that is suspended from poles placed outside the roadway.

The poles are placed with approximately 50-60 metre intervals along the entire ERS supplied road, as can be seen in figure 1. Only the right drive lane is equipped with ERS infrastructure. The truck, a hybrid truck from Scania, is equipped with a purpose built pantograph. The Scania hybrid truck has an electric drive train and a small battery, less than 20 kWh, enabling short electric range even outside the ERS. When operated outside the ERS, the combustion engine is normally engaged.

The interest in the demonstration facility has been high, with several hundred people attending the inauguration and as of August 2019, more than 2 500 people spread over 100 different occasions, have visited the demo site.

The main experience from the demo is that it was fairly simple to build the temporary 2 km overhead line system.

Since the start, three different trucks have driven more than 2 000 km on the 2 km long electric road. In general, the project has been successful, with lots of tests conducted and experience gained. As can be expected by an 3

innovative and pre-commercial project, challenges have been identified and improvements made as reported by Region Gävleborg (2018b). The most significant have been

• The technology works

• Winter operation

• Wear of carbon strip on pantograph

• Road pavement operations

• Roadside maintenance

From a technology perspective, the overhead line ERS in Sandviken has been successful in transferring electricity from the road to the vehicle, whilst the vehicle is driven down the road at normal speeds. Throughout the test period, challenges have been identified and addressed.

The winter conditions in Sweden include heavy snowfall and other conditions that can impair sensors and other technical systems. Initially, the pantograph operational system showed difficulties in identifying the overhead lines properly. This was addressed quickly and has worked well during winter conditions since then. However, accumulation of snow on the horizontal support beams for the contact wire is a remaining challenge. Snow can accumulate and then fall down on the vehicles using the road, thus resulting in a potential safety risk. Additional research projects are ongoing. This is not a unique challenge for overhead line systems. Also bridges and other objects crossing a road have similar challenges, but at a much lower frequency.

Fig. 1 Test site with overhead lines

At the test in Sandviken, the carbon strip on the pantograph had shown significant wear, concentrated on a rather narrow portion of the entire width of the carbon strip. The likely reasons for this high wear are a combination of both electrical and mechanical wear, the latter being the most important. The contact force might have been too high, together with the continuous re-adjustment of the pantograph in dynamic use. A new design, both hardware and software, of the pantograph has been presented and tests are ongoing in both Sandviken and in the demonstration facilities in Germany. The winter season 2019-2020 will be important to verify the function during, for Sweden, operational conditions.

ERS based on overhead lines have no direct impact on the road surface. However, due to the height of the contact wires, remedial road surface treatment with equipment using elevated operation heights such as asphalt trucks with a tipper constitutes a safety risk. A similar risk might occur for forage operations with a long hydraulic boom. This could be addressed by adding additional maintenance requirements or different types of equipment.

2.2.2. Road-bound electric rail at Arlanda

The Arlanda ERS, which is based on a road-bound electric rail, has been in operation at a closed test site for several years, and in November 2017 the installation on a public road was started, as described by eRoadArlanda (2018).

During the winter 2017-2018 the electrical work and integration tests were completed and in April 11, 2018 the 4

demonstration facility on the public road was inaugurated. As for the other demo site, the public interest in the inauguration was high with over 300 people from several countries attending.

The ERS technology was developed by Elways and consists of an electric rail embedded in the road surface. The upper part of the electric rail is flush with the surface of the road, and shall fulfil the same friction properties as the rest of the road. A retractable power receiver mounted under the truck supports power transfer from the rail to the vehicle. The power receiver automatically connects and disconnects with the electric rail as soon as the vehicle enters or leaves the ERS. The Arlanda ERS consists of 50-meter sections that can be activated and deactivated individually, as the vehicle is progressing along the road. The 50-meter section reduce the risk of exposed powered rail when no vehicles are using the ERS. At speeds below 20 km/h, the electric rail will not be powered.

A fully electric truck has been developed within the ERS project. The original vehicle was a diesel powered DAF that has been converted by the Dutch company e-Traction. The complete diesel drivetrain has been removed and replaced with electric wheel motors. After conversion, the truck has the same basic properties as the original diesel truck, with no loss in drivability, weight or loading capacity. Since the start of the project the fully electric truck has accumulated a significant driving distance, however the distance driven whilst powered from the electric rail is limited.

Fig. 2 Road-bound electric rail (photo: eRoadArlanda)

The technological challenges with the road-bound electric rail in Arlanda have been higher compared with the overhead lines in Sandviken, as could be expected due to all the previous experience the overhead solution gained from the rail sector. However, the amount of knowledge generated from the Arlanda ERS demo site has been significant for pre-commercial procurement, road-bound ERS and ERS in general.

The visual impact of the road-bound electric rail is low as could be seen in figure 2. The total width is less than 15 cm. At the side of the road, there are control/switchboards every 200 metres.

The project has, compared with the overhead line project in Sandviken, started from lower level of maturity and thus face more technological and system challenges. The major experiences gathered as reported by eRoadArlanda (2018) are:

• The technology works

• Selection of material

• Friction

• Winter operation

• Road pavement operations

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The electric truck has been powered from the road-based electric rail in Arlanda, both on a closed test track and at the demonstration facility. Several challenges have been identified and addressed.

In the initial development of the road-based electric rail technology major component, the frame, of the electric rail was based on a composite material. The cost was high and the production quality low, thus it was decided to replace the composite rail with a concrete rail. Several tests were conducted on a closed test track before the concrete rail was installed on the demo site, on public road. At the top of the concrete rail, steel bars are attached to act as an electric grounding potential and wear protection. The electric rail was installed during the Swedish winter, at rather low ambient temperatures. During the following summer, temperature related expansion of the steel caused technical issues. These have been handled and a plan for future development of the technology, including the installation process was developed. Validation in an operational environment remains.

The basic requirement for road friction shall be fulfilled by the ERS technology. However, the stipulated procedure for measuring road friction is not suitable for a narrow longitudinal rail. When the friction on the road-bound electric rail was measured with the same method as used for road markings, it was in line with the current regulation for road friction.

The road-bound electric rail in Arlanda does not affect normal winter maintenance. However, the snow and ice clearance inside the rail add an additional maintenance activity. To support this the electric rail is equipped with heating cables to melt the snow/ice, and a special purpose maintenance vehicle has been developed. Additionally, the power receiver is equipped with a small plough-shaped attachment that removes minor debris from the rail. A more severe challenge is the sensitivity to salt used in winter road maintenance. The joints between the individual segments in the ERS initially allowed for penetration of saline solution, and result in a reduced impedance in the system. If the impedance becomes too low, the power cannot be activated due to safety requirements. The saline solution could also be accumulated in the rail causing a reduced impedance. The project is working on possible solutions to this problem, and further tests and verifications are ongoing.

As the road-bound electric rail is embedded in the road surface, conventional remedial road surface treatment operations are not possible. The existing pavement next to the rail needs to be milled and a new asphalt layer, at the precise height of the electric rail, must be added. This has been successfully demonstrated at the demonstration facility during 2019.

2.3. New demonstration facilities and ERS technologies

In 2018, the Swedish Transport Administration decided to launch a second pre-commercial procurement. The purpose was to gain knowledge about additional ERS technologies, and to allow them to be demonstrated on public roads, under Swedish summer and winter conditions. In April 2019 two different consortia were awarded to the third and last phase, i.e. to build the demonstration facility and deliver the requested knowledge. One of the consortia represented a road-bound electric rail, and the other an inductive solution.

The road-bound electric rail system developed by Elonroad in Lund can be placed either on the road surface or imbedded in the road. The system has previously been tested on closed test tracks in Sweden, thus the technologies have been validated in relevant (Swedish) environments, but not yet in operational conditions. The inductive ERS technology was developed by Electreon and has been tested in a relevant (Israeli) environment, but not yet in Swedish conditions. Both the road-based electric rail from Elonroad and the inductive system from Electreon have been tested with passenger cars.

During 2019-2020 both systems will be deployed on public roads and the function will be verified with heavy duty vehicles. An important goal for the projects is to get at least two winters in an operational environment on a public road.

3. Research and innovation platform for electric road systems

Since 2016 the Swedish Transport Administration and the Strategic Vehicle Research and Innovation program are funding a Research and Innovation Platform for Electric Roads (2018). The work of the R&I Platform is intended to create clarity concerning the socioeconomic conditions, benefits, and other effects associated with electric roads.

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They will investigate the benefits from the perspectives of various actors, implementation strategies, operation and maintenance standards, proposed regulatory systems, and factors conducive of the acceptance and development of international collaborative activities.

Within the Research and Innovation platform, two international conferences of ERS have taken place. The first conference was held in Sandviken 14-15 June, 2017. A visit to the two kilometre demonstration site in Sandviken was the first point on the program for the 80 experts and researchers from seven countries. On the international arena, participants from Germany presented both research and plans for at least two demonstrations on public highways, each about 5 km of electrified road in each direction. Participants from Israel and USA, presented activities around inductive systems whilst the companies Alstom and Bombardier presented their respective technologies. International Energy Agency (2017) stated that electric road systems have a key role to play in reducing CO2 emissions from road transport, as also included in their reports and the IEA strategies.

The second international conference on electric road systems was held in Stockholm Arlanda 13-14 June, 2018.

The number of participants grew to 119 participants from 11 different countries, including India, Japan and the United States, besides a large crowd from Sweden and Germany. The number of presentations increased from 15 to 22. In conjunction with the conference, a visit to the ERS demo site at Arlanda was arranged. The third conference took take place in Frankfurt, Germany 7-8 May, 2019. In parallel with the ERS conference in Frankfurt, the first of up to three demonstration facilities was inaugurated. The next ERS conference will be held in Sweden, 12-13 May, 2020.

4. Conclusions

In Sweden, two different ERS technologies have successfully been deployed. One is based on the overhead lines in Sandviken and the other on a road-based electric rail in Arlanda. There are many similarities and differences between the two technologies. Each individual ERS technology will affect the road construction differently, thus it was deemed necessary to evaluate additional ERS technologies to gain knowledge for a presumptive future deployment. Considerable amounts of knowledge and experience have been gained since the start of the project in 2015, and the interest from all over the world has been significant.

However, building a temporary and spatially limited demonstration facility does not mean that it would be equally easy to build a permanent and large-scale pilot or national deployment. A temporary facility can be built with manual and time-consuming exemptions. For the installation no road plan was considered necessary, something that a large-scale deployment would have to pass. The type approval of the hybrid and fully electric trucks equipped with a power receiver have been based on a national procedure, partly inspired by experiences from trolleybuses.

Another example is the UNECE regulation 100 (2013) which stipulates that a vehicle which is physically connected to the grid is not allowed to move by the vehicles own propulsion system. This regulation was not intended for ERS but will have an effect on conductive ERS. A large-scale deployment of ERS compatible trucks has to be based on prescribed type approval procedures. In the demonstration sites, the trucks are rather unique individuals that have been purpose built. For a large-scale roll out the production capacity needs to be developed.

There are also systems needed in a large-scale deployment that have not been included in the demonstration projects. Three of the more important sub-systems are

• Access control

• Energy metering and billing

• Autonomous safety system

None of these sub-systems have yet been demonstration in operational environment, on a public road and with vehicles in commercial operation. Safety is handled in the demonstration facilities but it includes one layer of manual over watch, which is not practical in a large-scale deployment. Overall, the two demonstrated ERS technologies have successfully showed that it is possible to power an electric truck from the road. However, additional verification is needed before any ERS is fully mature.

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Acknowledgements

The author would like to acknowledge the two demonstration projects in Sweden, Region Gävleborg for the demonstration facility in Sandviken and Rosersberg Utvecklings AB (eRoadArlanda) for the demonstration facility in Arlanda as well as the Swedish research and innovation platform for electric road systems. This article would not be possible without these projects. Assistance provided by Nicholas Seagrowe in the final preparation of this article was greatly appreciated.

References

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