Life cycle assessments for electric road systems : Review and analysis of LCA studies

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Life cycle assessments for

electric road systems

Review and analysis of LCA studies

Lina Nordin

VTI PM D.nr.: 2016/0505-8.1

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Preface

This report represents parts of the work that has been going on within the research and innovation platform for electric roads at VTI. The platform, which is financed by FFI / Vinnova and the Swedish Transport Administration, is divided into several different work packages where work package two focused on the possible environmental effects that a roll-out of electric roads could have. The present literature compilation of life cycle assessments linked to electric roads is done within this work package.

Göteborg, June 2020

Lina Nordin

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Summary

Life cycle assessments for electric road systems Review and analysis of LCA studies

by Lina Nordin (VTI)

Life Cycle Assessment (LCA) studies are often used for assessing environmental effects that e.g. certain types of infrastructure investments might have during their lifetime. In Sweden the

development of electric roads has reached a level where a full-scale implementation is assumed during the coming decade. The goal is to find solutions for fossil free transportation and electric roads is an important part of this. Three different concepts of electrified roads are currently discussed in Sweden; the overhead catenary, the rail in the road surface and the inductive transfer from beneath the road surface.

Since electric road is such a new type of concept there are very few LCA-studies focusing on this type of infrastructure, and only one of the reviewed studies were comparing between all three concepts of electric roads.

The lifecycle of the road consists of the building and construction of the road, the maintenance and operations, the user phase and the end of life of the road. Electric roads are planned to be installed in already existing road infrastructure, hence different kind of electric road concepts will affect the roads in different ways depending on if the technique is to be buried, surface flush, or in the side area of the road.

Different concept will also need different types of maintenance and operations. LCA studies on the environmental effects of roads show that the largest emissions of CO2 come from the maintenance and

operations part of the road’s lifetime, if not considering the user phase. It will hence be crucial to investigate how maintenance will be affected by different types of electric road concepts.

Comparative LCA studies show that there is little difference between the environmental impact during the installation phase between roads and railroads. An installation of electric roads in an existing road is, however, an additional component in the environmental footprint of the road compared to the railroad, since additional technique will be installed in the road or roadside area. Meaning that an electric road will have a larger impact on the environment than a regular road during the installation phase. During the lifetime of the road this investment will, however, be paid back during the user phase of the road. Some of the LCA studies does, however, show that it will, depending on type of electric road concept, take several decades to pay back the investments of such a system. They also warn about investing in such a concept before all aspects are completely explored, as there is a risk that other techniques such as fast chargers will catch-up, making expensive road installations unnecessary.

The LCA study that compared between different concepts of electric roads has also included the reduced amout of asphalt that is needed for the road installed technologies. There are, however, some assumptions regarding maintenance and operations, made in the study that could be questioned. The few studies that are specifically investigating LCA on different kinds of electric road concepts, show that there is a lack of information and knowledge that is needed to be able to make viable assessments. These studies have furthermore not included the new types of technologies that are currently being installed during the two new demonstration projects for electrified roads in Sweden. One, in which the rail is placed on top of the asphalt minimizing the impact of the road construction by not needing to excavate the road surface, and the other one which is a new more flexible type of inductive

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8 VTI PM The conclusions of this literature review is hence that further investigations, accelerated and full-scale tests as well as analyzes of each respective electric roads concept are needed before it is possible to determine which type of electric road that is the most profitable alternative both in terms of

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Sammanfattning

Livscykelanalyser för elvägar

Litteraturgenomgång av LCA-studier av Lina Nordin (VTI)

Livscykelanalys (LCA) studier används ofta för att bedöma de miljöeffekter som till exempel en viss typ av infrastruktursatsning har under sin livstid. Utvecklingen av elvägar har idag kommit så pass långt att Sverige planerar för implementering av elväg inom det närmaste årtiondet. Det handlar om att snabbt hitta lösningar för att skapa ett fossilfritt transportsystem och där är elvägar en intressant komponent. När det gäller elvägar i Sverige finns det tre olika koncept som brukar diskuteras. Det handlar om elväg genom luftledningar, räls i vägbanan eller induktiv överföring under vägen. Eftersom konceptet elväg är så pass nytt finns det endast ett begränsat antal LCA-studier som undersöker miljöeffekter av elväg, och endast en som faktiskt försökt att jämföra mellan de olika koncepten.

Vägens livscykel består i dess uppbyggnad, underhåll, användning och avveckling. Elvägar planeras att implementeras i befintlig väginfrastruktur vilket gör att de olika koncepten kommer att påverka vägen på olika sätt beroende på om tekniken ska grävas ner i vägkonstruktionen eller finnas i sidoområdet.

De olika teknikerna kommer också att kräva olika typer av underhåll och driftåtgärder. LCA-studier gällande vägars miljöpåverkan indikerar att det är just drift och underhåll som kräver mest CO2 under

vägens livstid, bortsett från användningen av vägen. Det kommer alltså att vara avgörande att titta på hur underhållet av en elväg påverkas i förhållande till andra typer av lösningar.

Jämförande LCA-studier gällande väg och järnväg visar på att det inte är någon större skillnad i miljöpåverkan vid installationsfasen mellan dem. Däremot innebär en installation av elvägsteknik ytterligare en aspekt som påverkar vägens miljöavtryck jämfört med järnvägen, i och med att ytterligare teknik ska installeras i eller bredvid vägen. Det gör att en installation av elväg i vägen kommer att ge en större påverkan än en vanlig väg i installationsfasen. Det kommer sedan att kunna tas igen under användningsfasen av vägen som är den enskilt största posten. Dock visar vissa studier att det kommer att ta flertalet årtionden innan kostnaderna för installationen har betalats tillbaka, givetvis beroende av vilken typ av teknik som ska installeras. Samtidigt lyfts en varning gällande att bekosta dyra installationer innan dessa aspekter är utredda. Det finns en risk att annan teknik kommer ikapp där omfattande installationer i och runt vägen kan bli överflödiga inom kort.

Den LCA-studie som jämfört mellan de tre olika koncepten har även inkluderat den minskade mängd asfalt som behövs för de tekniker som installeras i vägen. Däremot har ett antal antaganden gjorts som skulle kunna ifrågasättas gällande vinterdriftsåtgärder och underhållsåtgärder. De få studier som specifikt riktat sig mot LCA på elväg visar att information och kunskap idag saknas för att kunna göra bedömningar som är helt rättvisande. Dessutom har dessa studier inte inkluderat de senaste typerna av tekniker som kommer att användas i två nystartade demonstrationsprojekt, där den ena kan läggas på vägen utan något större ingrepp i vägbanan, och den andra är en ny typ av induktiv teknik som ska påverka vägens konstruktion i mindre utsträckning än tidigare beprövade koncept.

Slutsatsen av den här litteraturstudien är således att ytterligare undersökningar, accelererade och fullskaliga tester samt analyser av respektive elvägskoncept behövs innan det går att avgöra vilken typ av elväg som är det mest lönsamma alternativet både i fråga om miljö och konstandseffektivitet.

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1. Introduction

Electric road systems (ERS) is the concept of using the road infrastructure to charge and power up the powertrain of a vehicle dynamically while driving. It is often the range of the battery that is discussed when considering using electrical vehicles rather than internal combustion engine (ICE) vehicles. Callahan and Lynch (2005) mentioned the range of the battery to be the most challenging part in using electrified busses in city traffic as there would be troublesome to plan routes depending on short charging range.

Providing green and fossil free energy to vehicles while driving will not only save time and increase traveling distance but possibly also reduce the size of the batteries. If a vehicle can be charged or powered while driving, there is no need for large powerful batteries. With smaller batteries there will be more room for freight and the need for rare earth elements will be less, than if electric vehicles were to rely on stationary charging (Olsson, 2014). This is of course if the ERS system can provide the possibility to charge the battery in such a way that the batteries state of health will be kept at a high level.

There are basically three different kinds of ERS that is considered for deployment in Sweden. These are the conductive overhead, the conductive in road rails and the inductive technologies. There are of course different solutions for each of the concepts and many different technology developers

promoting their own solution. In the following section, the basis of each concept is described.

1.1. Conductive overhead

The conductive overhead concept is much like trolley buses, where a pantograph is installed on top of the vehicle to connect to overhead cables. The difference from a trolley bus is that the pantograph will disconnect as soon as the vehicle changes lanes or if the driver wants to interrupt the connection for other reasons. It is hence not constantly connected to the power cables which makes the system more flexible. According to Cooney (Cooney et al., 2013) the flexibility was one of the main reasons why electric powered trolley busses in the United States where replaced by ICE busses. There are several studies regarding ERS that focuses on the Conductive overhead solution ((Björkman, 2013; Schulte and Ny, 2018; Schulte, 2015))

1.2. Conductive rails

This concept is more comparable with trams or light rails. Alstom has developed a type of tram that gets the power from the rails in the road rather than from power cables in the air. This kind of concept is adapted to the conductive rail solution, where a pick-up arm is transferring power conductively from beneath the vehicle (Olsson, 2014). The rails are installed in the road surface which will have an impact on the lifetime of the surface. From maintenance of tramways it is clear that a specific kind of cracks and damage will occur along the boundaries between the rail and the asphalt (Hedström, 2004). However, the pressure from the pick-up on to the rail is much less than the pressure that comes from a tram that runs on the rail. The concept is, like the overhead technology, flexible and the pick-up will disengage as soon as the vehicle makes a side maneuver.

1.3. Inductive techniques

Instead of transferring energy conductively with some sort of pick-up, the inductive technologies transfers energy wirelessly, through either magnetic coupling between primary coils, usually consisting of copper, embedded within the road construction to a receiving secondary coil in the vehicle or through resonance in the system (Chen, 2016). There are several different inductive technologies that have been evolving during the last decade, such as Primove, Olev and Electreon (Bateman et al., 2018). One of the inductive technologies are to be tested in a new demonstration site in Sweden (Swedish Transport Administration, 2019).

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1.4. Aim

The aim of this literature review was to analyze previous Life Cycle Assessment (LCA) studies to understand what kind of differences the deployment of electric roads might have, compared to a regular road and its energy use. Since ERS is such a new and developing concept there are, up to this date, only a few LCA studies published, hence LCA of similar technologies will also be included. The specific aims are to:

• compare between different types of ERS to recognize where there might be differences between the concepts.

• understanding differences between conventional roads as compared to ERS • understanding differences between ERS and stationary charged electric vehicles •_{analyze existing LCA studies on ERS to evaluate how useful the results are}

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2. What is LCA?

Life cycle assessment analysis is a method that can be used to evaluate the environmental impact of a product or process. The method is standardized by the International Organization for Standardization (ISO) in ISO 14040:2006. This standard includes four phases that needs to be included in the analysis. The first is the definition of goal and scope, the second is the inventory analysis phase, the third is the impact assessment phase and the last is the interpretation phase.

The use of LCA is very common to compare the environmental impact of different transportation modes and typically comparisons between electrical vehicles and ICE vehicles. The method

investigates the impact that each process in the lifetime of a technique has on the environment, starting with the production phase. The idea is to give a more holistic view of a product from the cradle to grave, i.e. from the production to the end of life. This means that all components that the product is used of will need to be inventoried as well as the process to produce those components. For electric vehicles for instance the discussions have long been the environmental impact of producing batteries. Earlier studies have concluded that Li-ion batteries have the least impact on the environment

(Matheys et al., 2007; Notter et al., 2010; Samaras and Meisterling, 2008). However Vandepear et al. (2017) also involved the energy to build the battery as well as battery replacement in their study, which resulted in higher CO2 emissions. They concluded that the production of Li-ion batteries had

much larger impact in the environment and climate than Li-Metal-polymer batteries had. It is hence important, when using LCA to compare between two products or techniques, as in the quest of determining the most environmentally friendly ERS technology, to compare the same issues in the same way. This is where the functional unit (FU) comes in.

The functional unit can in comparative LCA be used as a reference unit. When it comes to pavement LCAs the FU should include physical properties such as structural components, material properties and design as well as consider other factors such as traffic load (AzariJafari et al., 2016). However, with different FU the results of the same study might differ. It will hence be difficult to compare the results of different LCA if the FUs are different (Santero et al., 2011). In the Santero study (2011) they mentioned the functional unit used by Stripple (2001) typical for a road in Sweden with 5000 vehicle passes a day and a life time of 40 years. While other studies will set a functional unit based on the conditions of their country or region. Carlson (2011) also mentioned the difficulty in comparing between different countries even in Europe as no road is equal to the next.

LCA studies also includes sensitivity analysis where the uncertain parameters in the analysis are discussed in terms of the impact a variation of such uncertain parameters might have on the results. Reza et al. (2014) showed that by increasing the life length of a pavement from 50 to 70 years the energy use of maintenance and operations of the road would increase with 40%.

2.1. LCA in road and pavement studies

LCA studies are often used to compare between different pavement construction methods or materials. They can also be used to investigate the effect that different maintenance aspects might have on a road such as the study by Wang et al. (2012) where the decreased rolling resistance of different pavements on high traffic highways would cause a reduction in energy use and greenhouse gas emissions that is larger than what the energy use and GHG emissions of material production and construction would be. On roads with less traffic the circumstances would be the opposite. The study by Wang et al. (2012) uses the time for pay back of the investment in rehabilitation as an influential factor. For roads with a lot of traffic the payback time would be shorter because of the reduction in fuel consumption as a cause of a smoother road is larger because of the higher traffic load. The payback time on a road with less traffic would hence be longer.

It seems, however, that it is difficult to generally compare the energy use and environmental impact of roads and pavements using LCA since they are so different. Every road is unique and has its own

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14 VTI PM separate conditions. Carlson (2011) does, however, conclude that traffic or the use of roads is the most energy consuming part of the life of a road.

If the road construction and maintenance are the main concerns, then it is the construction phase and material use that will be the biggest contributor with as much as two thirds according to Jullien et al. (2014), and maintenance of the road would stand for the rest.

Stripple made a comprehensive LCA study in 2001, regarding road construction and maintenance of a road. This study is often referred to in LCA studies regarding roads (e.g. (AzariJafari et al., 2016; Balieu et al., 2019; Jullien et al., 2014)). It is however important to consider the different road designs as well as maintenance rules and schedules when trying to adapt one method between different countries, as stressed by Jullien et al. (2014).

This is also interesting when it comes to electric roads. In discussions regarding ERS infrastructure at a workshop during FIRM 19, in Brussels, regarding standardization of electric roads it was also discussed if the maintenance scheduling should be standardized, where the wear and tear of the system should be and what materials to use (Almestrand Linné, 2019). This might become increasingly important as ERS-users would want to be able to go between countries using the same vehicle hence expect the same standard of the road.

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3. LCA in ERS

The ERS as a concept is rather new and there are only a few LCA studies done on different kinds of ERS technologies. Because there are yet no ERS deployed on conventional roads with regular traffic, it is also difficult to estimate the life cycle costs of such a system. The few studies that are reviewed here have hence had to use existing information and cost assessments from other types of

transportation modes.

The ERS as a concept consists, not only, of a road and the construction, maintenance, operations and use of this road but also on electric power supply and the infrastructure connected to that. It is basically a combination of different parts of a railway/tramway and a road, sometimes and depending on type of ERS technology, it concerns the rails in the roads such as those used for tramways and sometimes it concerns the overhead power lines. To be able to perform an LCA it is important to consider the changes that the implementation of ERS might have on the regular road and the maintenance and operations of it.

Other types of transportation modes that could be used for comparisons are trains, tramways and trolley busses. When it comes to trains and tramways it is actually the concept of tramways that is the most similar to ERS due to the same size of voltage (7-800 V) as well as the integration in a regular road, while trolleybuses would be the concept that is most similar to the catenary solution.

3.1. Electric vehicles

There are numerous LCA studies concerning electric vehicles, often including comparisons between different types of transportation modes, such as between electric vehicles (EV) and other different powertrain vehicles including diesel driven vehicles. Such studies may include either hybrid or electric buses, trolley buses or diesel driven vehicles (Bi et al., 2015; Cooney et al., 2013; Lewis et al., 2014; Nordelöf et al., 2014; Singh and Strømman, 2013). When it comes to studies regarding electric vehicles they often considers manufacturing, mainly regarding batteries, and emissions (Matheys et al., 2007; Notter et al., 2010; Peters and Weil, 2018) and rare earth elements (Pavel et al., 2017). The reuse of batteries or their parts is also becoming more interesting and included in recent studies (e.g. (Boyden et al., 2016)). When batteries are no longer efficient enough to be used in EVs, it is still possible to use them as energy storage in other areas of energy use such as residential use or power grid services (Casals et al., 2017; Hu et al., 2017). Lithium-ion EV batteries can be used for another seven to ten years after they are no longer efficient enough for EVs. When the storing capacity of the batteries are below 75% the best use is to dismantle the battery and use smaller parts for other purposes such as electric bikes (Casals et al 2017). The last part of the battery life is to extract metals such as nickel, cobolt, copper, lithium and iron for recycling purposes (Hu et al., 2017). This

procedure is so far, more expensive than mining new metals, but it is important to understand that it is possible for the sake of environment.

In a study on life-cycle energy and greenhouse gas emission footprints from heavy metro train by Del Pero et al (Del Pero et al., 2015) the acquisition of materials, manufacturing, use and end of life phases were investigated. It was concluded that the use-phase was the largest contributor, followed by the material acquisition. The large impact of material acquisition is based on the resources used and emissions from the extraction of iron and bauxite. A large part of this comes from producing the vehicles, heavy trains. The study focused on the vehicle and not the infrastructure around it.

Many LCA studies of electric vehicles or hybrid vehicles mentions that the user phase of the lifetime of the vehicles cost the most in terms of fuel use or electricity. Hence the type of fuel will be the most influencing factor. For electric vehicles it will, according to Cooney et al. (2013) all depend on the used type of energy mix. They concluded that, due to the electricity source, only 8 of the states in US would benefit from changing public transportation from diesel busses to electric vehicles.

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16 VTI PM Bi et al. (2015) compared plug-in charging buses with wirelessly charged vehicles (stationary). The results showed that the size of the battery could be reduced with 27-44% compared to a plug-in. The reduced weight of the battery would in turn result on 0.3% less energy use and 0.5% less GHG emissions than the plug-in buses. They also mentioned the importance of considering the origin of the energy used (Bi et al., 2015). This is not the only reason why they stress the need to fill the gaps regarding electricity grid management, but also to be able to balance the demand and supply of electricity. There is a growing concern regarding energy supply during rush hour or peak hour, which also needs to be considered when considering environmental impact. This is however out of the scope of this study.

3.2. LCA comparing with tramway, electric buses or trolleybuses

There are some resemblances between ERS and tramways or metros, electric buses and trolleybuses, hence an overview of life cycle studies for such types of transportation was included in the study. Such studies do however often focus on emissions per passenger kilometer (Chester et al., 2010; Clark et al., 2007; Puchalsky, 2005) and the results will hence be affected by the share of transit ridership as in the study by Chester et al. (2010), which compared energy and emissions for the three U.S metropolitan regions of New York, Chicago and San Francisco, where New York was the winner, much influenced by the larger share of transit ridership. The concept of using electricity divided by passenger kilometer could however of course be used in studies concerning freight on electrified roads instead. The

calculations could instead be emissions per vehicle km, and the results would depend on amount of freight transported using the ERS.

As described previously, most LCA studies that includes vehicles are focusing on material acquisition of the production of the vehicle or batteries of the vehicles, where little focus is on the roads or infrastructure that provides the possibility of using those vehicles.

Chester et al (Chester et al., 2010), did however, include vehicle operation and manufacturing as well as roadway maintenance, infrastructure operation and material production and Kliucinikas et al.(2012) did include the production of different types of fuels including the generation of electricity for

trolleybuses.

The comparative LCA study by Kliucinikas et al (2012) compared between busses powered by diesel, compressed natural gas or compressed biogas and trolley busses powered by natural gas or heavy fuel oil. They used the Life Cycle impact assessment (LCIA) which is divided into three damage categories – human health, ecosystems and resources. The lowest environmental impact was found to come from trolley buses using electricity generated from heavy fuel oil and natural gas as compared to fuel chains using diesel compressed natural gas and compressed biogas. However, when looking at the resource category of their study the compressed biogas powered bus was the better option as the biogas was produced locally, and renewable energy was used as compared with the diesel compressed natural gas which also needed to be transported from the extraction site. Hence, again the importance of knowing what to compare and how.

3.3. LCA comparing roads with tramway or railway

As the name implies, electric road system (ERS), concerns the road and the infrastructure that supplies electricity to it. Investigating how an ERS road will differ from a regular road will need to consider the difference between the materials used for the technology that provides electricity supply, as well as differences in maintenance and operations of the new type of technology or how the ERS technology will affect the maintenance and operations of the conventional road.

There are a few studies made in Sweden which are comparing the lifetime use of energy of a road with that of railways or tramways (Jonsson, 2005; Sandberg, 2011). They are looking at the construction of

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the infrastructure, the material used in the infrastructure as well as in vehicles and the production of fuel, which is in line with the concept of ERS.

It seems as if the energy use during the early construction phase is about the same for roads as for rail roads in terms of grubbing up, blasting and rock-removal work. Most energy is used during the production of materials used in the construction for both roads and railways but the energy is used in the production of base courses, sub-base courses and surface layers for the roads while it is used for the production and installation of the rails when it comes the railway (Jonsson, 2005).

When discussing reduction of energy use and emissions of greenhouse gases it is according to Jonsson (2005) important to not only focusing on the energy use of the user phase such as the use of fossil fuels or the reduction in CO2 when using electric vehicles instead of diesel fuels, but also considering

the energy use during the construction phase as well as maintenance and operations of the infrastructure. Streetlights is such a source. In urban areas streetlights constitutes for 50% of the energy use of the maintenance while it is only 5% in rural areas where there are no lights. Stripple and Uppenberg (Stripple and Uppenberg, 2010) performed an LCA of the railway and mentioned that for railways the user phase is very small due to the use of green energy mix. This is opposed to the user phase of a road which is often said to be the largest in the life cycle of a road. In terms of ERS, the impact on environment during the user phase will be hugely reduced, as long as the energy comes from fossil fuel and renewable sources. It will hence be interesting to look further into the construction and maintenance phases of the ERS.

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4. Can previous LCA studies be used to evaluate ERS?

As the concept of ERS is rather new to the market there are only a few LCA regarding different concept of ERS. There is only one that is comparing between the three different concepts of overhead conductive, in road conductive and inductive technologies. However, there are other LCA studies that are concerning the road infrastructure which can be used.

Schulte (Schulte, 2015) focused on overhead system and analyzed the solution by dividing the concept into five parts; the energy supply, the contact cables, the supporting masts, guard-rails and the current collector.

The LCA was comparing between stationary fast chargers and ERS and found that even though difficulties of retrieving information from manufacturers regarding material use, and the novelty of each type of concept it seemed as if the fast chargers would have a reduced impact on the environment compared with fossil fuel. The reductions in relation to the costs are, however, smaller than for ERS, but ERS will on the other hand produce more emissions than the fossil fuel system when it comes to ecotoxicity as a result of copper particles from the wear of contact cables. Schulte also mentions the risks of implementing a system such as ERS that is supposed to last for a long time compared to the fast chargers that can easily be replaced when better alternatives are available on the market. Since it was difficult to retrieve information regarding material from the different ERS developers in the world, Schulte used information from railway instead but with a few adjustments to better comply with the constraints of the ERS technology in question. The same was done for maintenance and operations. The wear of the contact line will most likely not be the same as for a railway solution. It seems, according to Schulte that maintenance and operations of the overhead solution is mainly regarding change and maintenance of the electric power system and the guard-rails.

Schulte and Ny (2018) compared between ERS and diesel driven freight transport using the four different sustainability principles. The first regards the use of raw materials and the emissions of greenhouse gases to the atmosphere. The second principle concerns emissions of persistent chemicals or NOx. The third states that nature must not be degraded by physical means, for instance by land use or the mismanagement of ecosystems. The fourth principle regards the human needs.

The Schulte and Ny study concluded that it is really the energy mix that plays an important part. Coal-based energy used in the ERS will cause the highest emissions of GHG (229g/tkm) and wind energy the lowest (31 g/tkm). The use of diesel (165 g/tkm) would be in the middle of these two.

When it comes to the environmental payback time the study concluded that for short payback times of 5 years the traffic volume needs to be high, more than 1400 trucks per direction and day. Since the environmental payback time depends on the kind of energy mix used, the results will improve if using wind energy instead of the EU-mix that was used in this example. Looking at the economical payback time the result is a bit different. With high initial investment cost the system may need to be used for several decades before it is payed back economically.

Björkman (2013) also conducted a comparative LCA. Three different kinds of trucks where compared for the transportation of iron ore from the mine in Kaunisvaara, Pajala to Svappavaara. One

conventional truck with combustion engine was used as reference. The second was a parallel hybrid electric version of the same truck and the third would be powered from overhead conductive lines. The study concluded that both the electrical alternatives were better than the conventional one, but the truck using the overhead power lines (the ERS truck) would be the best choice, because of the diesel use from the parallel hybrid. This study concluded that it is the user phase of the life cycle that is affecting the environment the most, hence the electrical alternative would be the best option. It is also mentioned that even though the electric mix is from “dirtier” sources, the ERS truck would still be the best alternative.

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The study by Björkman compares between vehicles and materials used in the infrastructure but it seems to lack information regarding installation or maintenance and operations of the ERS-system. When it comes to wireless technologies there are some studies, mainly in the USA, that are

investigating the use of electric vehicles charged by wireless power transfer (WPT) techniques. However not a lot LCA. Quinn et al. (2015) did a techno-economic analyses as well as an LCA on this kind of concept. They compared vehicles with internal combustion engines with electric vehicles charged with WPT in regard to payback time of the system as well as on environmental impacts. The societal payback times in their study ranged, at a 20% penetration, between 1.04 and 2.6 years

depending on only interstate or interstate as well as urban roadways respectively. These short payback times were accredited to the decreased costs for operation of the vehicles in terms of efficient energy transfer and lower costs of electrical energy than petroleum-based energy. The environmental savings in Quinn et al., were calculated to 49% CO2 compared to the combustion engines. They did also

mention that the emissions that came from the electric solution would be centralized and depend a lot on the kind of energy used in the power plant. Hence as Cooney et al. (2013) concluded the gains would be different in different states of the USA, and that even though improvements in battery technology could reduce the environmental impact, it is still the electricity grid that is the main variable in the calculations.

This is not only limited to the USA, questions regarding the origin of the energy as well as type of energy mix is highly relevant in terms of calculating the environmental gains from ERS, and often referred to in literature (Lindgren, 2017).

Schulte and Ny (2018) also mentioned the payback time but regarding environmental aspects and it was calculated to be less than five years when focusing on the overhead conductive solution. Their study did not include other ERS technologies which are less material demanding but did as Quinn (2015) compare with a regular internal combustion engine vehicle.

The above-mentioned studies did not compare between the three different concepts of ERS and when doing so the construction, maintenance and operations of the system needs to be considered. Balieu et al. (2019) tried to do this. They set the functional unit to be a 1 km long stretch of a motorway with either pantograph, conductive rail or inductive technologies.

They concluded that it is the maintenance operations phase of the life cycle that has the highest CO2

emissions, for all concepts including a traditional road. However, it seems from the study that the traditional road will have the least impact on CO2 both in construction, maintenance and overall.

By comparing the three ERS concepts they concluded that the rail solution had the least impact on CO2 as a total and the overhead catenary technology had the highest impact, due to the large amount of

materials used in the construction part of its lifetime. Comparing the three concepts during the maintenance phase the catenary technology would instead have the least impact on CO2. There were

however a lot of energy intense maintenance operations excluded from their study due to the exclusion of safety rails which could have an impact on the environmental effects of each ERS concept (this is further elaborated in section 4.1).

Baliue et al. (2019) did however in accordance with other studies mark the importance of keeping the roads in good conditions and Ceravolo (2017) indicated that monitoring of the roads and ERS

infrastructure will be crucial to keep the solution sustainable. Their study focused on inductive or wireless technologies, but questions regarding monitoring and maintenance of e-roads and structural health monitoring to detect damage evolution within the infrastructure are useful for conductive technologies as well, especially the in-road solutions with rails.

The Balieu et al. (2019) study differs from all the others because it actually aims at comparing between the three different ERS concepts. However, each study needs to set some limitations and for

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20 VTI PM the Balieu et al. study the limitations are made by excluding a few parameters, including guard-rails with the explanation that this will not differ between the different ERS concepts.

There are however a few differences regarding the different technologies that are concerned by this.

4.1. Differences in road maintenance operations due to ERS

technologies

Guard-rails need to be installed along roads in rural areas where there are steep slopes, water, or other obstacles in the roadside area closer to the road than 10 m, the so-called safety zone. If there are no obstacles, there will be no need for guard rails along such rural roads. Road lighting is another type of obstacle that needs guardrails but since there is normally no road lighting along the roads in rural areas (Carina Fors, 2014; Swedish Transport Administration, 2015) such guardrails will not be needed in that sense either.

If, however, looking at installing overhead catenary masts in the roadside area the need for guardrails will be apparent, and also, differ from what is usually needed along such road stretches. The difference here will also be apparent when considering the other ERS concepts as they will not need guard rails as long as switching boxes and transformer stations (sub stations) are placed outside of the 10 m safety zone.

There will hence be important to consider the different types of maintenance and operations activities and how they are affected by the presence of guard rails.

Harvesting or side-verge cutting is one example of a road side activity that according to Bäckström (2014) costs close to one billion SEK every year. That is almost one eight the total cost of road maintenance and operation in Sweden every year. All vegetation in the roadside area is to be cut to a width of 10 meter from the road during summer and again to a width of 1.6 meter before winter. Tests regarding roadside harvesting in Sweden showed that it took 17 min/km to cut grass using regular technique along roads with no safety rails compared to 35 min/km on roads with guard rails (Bäckström, 2014).

As described by Nordin (2019) costs for harvesting the roadsides along ERS roads with overhead conductive technologies might thereby increase by 50% along stretches of roads where there is normally no need for guardrails. When it comes to costs in road maintenance operations it will mainly concern costs regarding the fuel use since the activity often includes wheel-loaders with cutting arm as well as TMA (truck mounted attenuator) vehicles for safety precautions. These are thereby important factors to include in LCA studies regarding ERS.

Winter maintenance operations

Guard rails will also affect snow removal activities as the rails might be in the way of pushing snow off the roads. Different kinds of safety rails will affect snow ploughing efficiency in various ways, e.g. by the piling up of snow against the rails. This might even be the case at roads with rails with an open profile (Karim and Magnusson, 2009). Karim and Magnusson (2009) concluded that the operators of the ploughing vehicles had to keep a distance of 30 to 40 cm from the rail to not cause damage on rails or ploughing blades. In an LCA perspective this should of course be included to make the comparison between these three types of technologies more viable.

The Balieu study includes winter maintenance and rehabilitation operations as these, as they describe, might differ between the different technologies. The analysis is based on figures from Stripple (2001). It is the frequency of winter maintenance operations that Balieu et al. (2019) has used to compare between the different concepts and hence their distinction of relationships between the three technologies will be of most interest. Regarding winter maintenance they assume that, to be able to ensure good efficiency in power transfer, the inductive, as well as, conductive rail technologies will

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need twice the amount of winter maintenance than will the overhead catenary solution. This

assumption should be tested since the analysis from the Stripple study are from 2001 and the winter maintenance operations might have changed since then, including stricter follow-up routines. Also, the impact from guard rails are neglected in the Balieu study since they assumed that all technologies would use such rails similarly.

It is furthermore not included in the study that electrical cables in the overhead solution might need to be de-iced as well. ERS manufacturers have indicated that they intend to heat the cables or rails to melt frost or ice. Studies have, however, shown that there seem to be an increased wear of the wire if the cable is heated (Ding et al., 2012; Wu et al., 2018).

Studies regarding tramways in Sweden shows that cables are sometimes de-iced instead, by spraying the cables with glycerin using a specific vehicle. From field tests of anti-icing of wires in Turkey it was shown that arc formation could be reduced by performing anti-icing and thereby also have the potential to reduce the wear of the wire as well as maintenance costs (Er and Çakir, 2018). To get an as good effect as possible the spraying needs to be done at a speed of no more than 20 km/h. The treatment lasts for 12-18 hours (Drexler and Johansson, 2013). This again indicates an increased amount of maintenance activities that might cause delays in traffic as well as increase the use of maintenance vehicles.

Rinsing of rails

Maintenance activities connected to the rails in tramways can be used as reference when trying to compare with the conductive rail technology. Such maintenance could for instance be the rinsing of the rails to remove dirt and particles that get stuck in the rails. For tramways in Gothenburg the rails are rinsed twice every day (Khoury and Grönskog, 2015). Rinsing of ERS rails will probably also occasionally be needed and add to the maintenance activities that will differ between the different technologies.

The maintenance activities mentioned above are not included in the existing LCA studies, and as the maintenance operation phase has the highest CO2 emissions, for all concepts including a traditional

road (Balieu et al., 2019) it should be included in future LCA.

4.2. Material and construction of ERS

The Balieu et al. (2019) study included the construction and maintenance phases of the life cycle of the road infrastructure. Their study is the only one considering these aspects. It is also interesting that, installing the embedded technologies i.e. rails and inductive technologies, will need less amount of asphalt. This will of course depend on the different types of technologies and the volume of the installed technology.

The pantograph solution could be compared to the Schulte and Ny study (Schulte and Ny, 2018). The raw material is mainly concerning copper and steel, however Schulte and Ny also included polytene and fiber glass used in the catenary masts. It is however unclear as to if this is used in the electric road solution or rather is something that is used on railways. Schulte and Ny also include roadside barriers or safety rails which seems to be excluded from the Balieu et al. (2019) study. The conductive rails used in the Balieu study consist of steel. The inductive technology uses copper coils and concrete. But it will depend on type of technolgy considered.

The wear and tear of each type of electric road concept needs to be identified. Some estimations have been presented from the two ongoing demonstration projects in Sweden, but those tests have been limited to the test vehicle and only during a few measurements. The estimations are not to be compared with a full-scale implementation with regular traffic or accelerated tests. Such tests are needed and should be included in future LCA studies.

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22 VTI PM To understand some of the maintenance needs of the rail system it could be useful to compare

maintenance of tramways with maintenance of ERS infrastructure including rails. Damage or maintenance needs of roads with rails will depend on many factors such as type of road foundation, climate, type of regular traffic load etc. (Hedström, 2004). Since ERS differs from railways in, e.g. that they will not use rail gears, it is important to separate what kind of maintenance that is needed on railways in comparison with what will be needed on ERS. This is especially important if basing an LCA estimation of ERS with an LCA for railways.

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5. Discussion

Differences between concepts

According to Balieu et al. (2019) the differences could be in winter, where the efficiency of the energy transfer might be affected by snow and ice both for the rail and inductive concepts.

There might however be other issues to consider when it comes to the overhead catenary solution as this technology will need other kinds of winter maintenance operations to de-ice the cables, as is done for tramways. Instead of adding anti-icing agents it might be possible to heat the cable. This will however increase the wear and tear of the cable/carbon strip.

Other differences will be the sweeping of the rails that are embedded in the road surface. This will be a maintenance activity that is only needed on the rail solution. When comparing with tramways they might sweep as often as twice a day because of dirt and leaves etc. get stuck in the gap between the rails. It is assumed by the manufacturer that this will not be needed during full operation as the pick-up of user vehicles will remove dirt while picking up energy from the rail. This is however not yet been tested and is so far only assumptions.

For the overhead catenary solution there will be the difference of using a safety rail at the side of the road to protect road users from driving into the supporting masts of the overhead solution. Having safety rails will impact maintenance operations such as side verge cutting, as well as snow ploughing. The costs might become twice as expensive due to more complicated cutting routines.

Differences between conventional roads as compared to ERS

There are a lot of differences between conventional roads and roads with ERS. Apart from safety routines regarding electric work it is important to understand that electric cables or other devices might be hidden beneath the road surface. This might affect regular maintenance operations such as

resurfacing where the top layers of the asphalt are scraped off the road before new is laid. This might have an impact on the electric parts that are buried beneath.

Cracks, and freeze and thaw mechanisms might also have an impact not only on the road but also on the electrical parts. If something is malfunctioning beneath the road it might be more costly to remove and replace those parts than to just seal the cracks as would be done on the regular road.

All of the above-mentioned aspects need to be considered in an LCA to be able to make comparative LCA that will be more accurate. It is however difficult to know these things before a large-scale implementation of ERS is available. More investigations should be done.

How will the conventional road infrastructure be affected during certain operations? Will traffic be affected if a power line is torn down? There are examples from the railway that such failures will bring about large impact in traffic delays. For safety precautions it might be best to close the affected lane which of course will have an impact on the traffic.

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24 VTI PM

6. Conclusion

It is possible to use LCA towards, to some extent, comparing between the different concepts of ERS, but the results should be considered with caution at this stage. Using LCA to compare between the ERS and conventional road might also be a little more complicated than what is described in existing literature. The present review can conclude that several maintenance activities are not included in the LCA studies, and as the maintenance part of the road has the largest impact on the environment it should be.

The information to understand or evaluate the effect that different maintenance activities might have will however not be completely available until a large-scale implementation of ERS has been realized and used for some time.

Aspects to include in a comparative LCA regarding ERS

When comparing between the different ERS, it is important to know the amount and kind of materials used in the various concepts. Since manufacturers seem to be hesitative of supplying information about this the information is instead taken from other roads or railway LCA studies.

It is furthermore interesting to include other road equipment such as safety rails where the use of such equipment is differing between concepts. The wear of each system should also be included as well as routines for exchanging malfunctioning parts of the system, including type of vehicles used for that kind of activity as well as their fuel use.

It is furthermore important to remember that the road area is a harsh environment and equipment need to sustain wear and tear as well as salt spray and hard weather. The overhead catenary solution seems to be built using the same technologies as the railways hence the same kind of problems might occur, apart from the rails and gears. The use of the catenary system in the road environment is however new and questions regarding what impact salt spray might have on the overhead catenary system could be interesting to investigate further.

The inductive technology would be affected by pressure from above and freeze and thaw within the road surface. The energy transfer might also be affected by ice and snow, making it more crucial to remove ice and snow as soon as possible. The technology is also not suitable in areas where the roads are not de-iced during winter but rather are kept winter white, meaning that the surface layer consists of packed ice and snow. Snow might also pile up along areas where there are safety rails or in open areas where the wind is causing snow to drift.

To be able to make a good comparison between technologies the geographical area is important to consider. One technology might be better suited in one area but not as good in another.

Of the reviewed studies, the Baleu study is the most interesting one, as it actually aims at comparing between different ERS technologies during the construction, maintenance and operation phases. They concluded that the traditional road would have the smallest environmental impact in terms of CO2

emissions, and the overhead catenary concept the largest. The rail solution would according to their study have the least impact on the environment of the three investigated ERS concepts.

Balieu et al. (2019) also mentioned that by using finite element simulation it has been shown that with the embedded inductive technology the road gets more damaged. They concluded that when

comparing between the three concepts the damage caused by the embedded technology would be in the line of three times that of a conventional road, while the rail solution would be twice that of a conventional road.

The study did, however, not included the new types of technologies that are currently being installed during the two new demonstration projects for electrified roads in Sweden. One, in which the rail is placed on top of the asphalt minimizing the impact of the road construction by not needing to excavate

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the road surface, and the other one which is a new more flexible type of inductive technology. This type of flexible embedded technology might have less deteriorating effect on the road construction. Further accelerated tests are needed on these types of technologies to be included in future LCA.

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References

Almestrand Linné, P., 2019. Standardisation of Electric Road Systems- DRAFT REPORT FROM WORKSHOP AT FIRM 19- 28 MARCH 2019, BRUSSELS- on file with author, to be published late 2019 (Collers Draft report). VTI.

AzariJafari, H., Yahia, A., Ben Amor, M., 2016. Life cycle assessment of pavements: reviewing research challenges and opportunities. Journal of Cleaner Production 112, 2187–2197.

https://doi.org/10.1016/j.jclepro.2015.09.080

Bäckström, A., 2014. Röjning och slåtter med flerarmad slåttermaskin. SBUF Informerar 14:19 10. Balieu, R., Chen, F., Kringos, N., 2019. Life cycle sustainability assessment of electrified road systems. Road Materials and Pavement Design 20, S19–S33.

https://doi.org/10.1080/14680629.2019.1588771

Bateman, D., Leal, D., Reeves, S., Emre, M., Stark, L., Ognissanto, F., Myers, R., Lamb, M., 2018. Electric Road Systems: A Solution for the Future?

Bi, Z., Song, L., De Kleine, R., Mi, C.C., Keoleian, G.A., 2015. Plug-in vs. wireless charging: Life cycle energy and greenhouse gas emissions for an electric bus system. Applied Energy 146, 11–19. https://doi.org/10.1016/j.apenergy.2015.02.031

Björkman, A., 2013. Comparative LCA of Electrification Alternatives for Long Haul Trucks The Case of Iron Ore Powder Transportation from the Pajala Mine (Master of Science Thesis in the Master Degree Program Sustainable Energy Systems No. 2013:4). CHALMERS UNIVERSITY OF TECHNOLOGY, Gothenburg.

Boyden, A., Soo, V.K., Doolan, M., 2016. The Environmental Impacts of Recycling Portable Lithium-Ion Batteries. Procedia CIRP 48, 188–193. https://doi.org/10.1016/j.procir.2016.03.100

Callaghan, L., Lynch, S., 2005. Analysis of electric drive technologies for transit applications: Battery-electric, hybrid-Battery-electric, and fuel cells.

Carina Fors, 2014. Vägbelysningshandboken.

Carlson, A., 2011. Life cycle assessment of roads and pavements - Studies made in Europe (VTI-rapport No. 736A). VTI, Linköping.

Casals, L.C., García, B.A., Cremades, L.V., 2017. Electric vehicle battery reuse: Preparing for a second life. Journal of Industrial Engineering and Management 10, 266–285.

https://doi.org/10.3926/jiem.2009

Ceravolo, R., Miraglia, G., Surace, C., 2017. Strategy for the maintenance and monitoring of electric road infrastructures based on recursive lifetime prediction. Journal of Civil Structural Health

Monitoring 7, 303–314. https://doi.org/10.1007/s13349-017-0227-6

Chen, F., 2016. Sustainable Implementation of Electrified Roads : Structural and Material Analyses. Chen, F., Balieu, R., Córdoba, E., Kringos, N., 2019. Towards an understanding of the structural performance of future electrified roads: a finite element simulation study. International Journal of Pavement Engineering 20, 204–215. https://doi.org/10.1080/10298436.2017.1279487

(28)

28 VTI PM Chester, M.V., Horvath, A., Madanat, S., 2010. Comparison of life-cycle energy and emissions

footprints of passenger transportation in metropolitan regions. Atmospheric Environment 44, 1071– 1079. https://doi.org/10.1016/j.atmosenv.2009.12.012

Clark, N.N., Zhen, F., Wayne, W.S., Lyons, D.W., 2007. Transit Bus Life Cycle Cost and Year 2007 Emissions Estimation.

Cooney, G., Hawkins, T.R., Marriott, J., 2013. Life Cycle Assessment of Diesel and Electric Public Transportation Buses. Journal of Industrial Ecology 17, 689–699. https://doi.org/10.1111/jiec.12024 Del Pero, F., Delogu, M., Pierini, M., Bonaffini, D., 2015. Life Cycle Assessment of a heavy metro train. Journal of Cleaner Production 87, 787–799. https://doi.org/10.1016/j.jclepro.2014.10.023

Ding, T., Chen, Guang.-X., Li, Yu.-M., He, Qiu.-D., Xuan, Wen.-J., 2012. Friction and Wear Behavior of Pantograph Strips Sliding Against Copper Contact Wire with Electric Current. AASRI Procedia 2, 288–292. https://doi.org/10.1016/j.aasri.2012.09.048

Drexler, M., Johansson, V., 2013. Vinterproblematik för spårväg - Förslag på åtgärder i underhåll och projektering baserat på erfarenheter från städer med befintlig spårväg.

Er, Ü., Çakir, F.H., 2018. Urban Light Rail Transportation Systems Catenary Line Anti-Icing Applications, Laboratory and Field Tests. Anadolu Üniversitesi Bilim Ve Teknoloji Dergisi A - Uygulamalı Bilimler ve Mühendislik 19, 433–442. https://doi.org/10.18038/aubtda.385262 Hedström, R., 2004. Attraktiv och effektiv spårvägstrafik: den moderna spårvägens egenskaper, funktioner och potential för urbana och regionala persontransporter.

Hu, Y., Cheng, H., Tao, S., 2017. Retired Electric Vehicle (EV) Batteries: Integrated Waste Management and Research Needs. Environ. Sci. Technol. 51, 10927–10929.

https://doi.org/10.1021/acs.est.7b04207

Jonsson, D.K., 2005. Indirect Energy for Road and Railway Transportation in Sweden; Indirekt energi foer svenska vaeg- och jaernvaegstransporter (No. FOI-R-1557(ed.2)). FOI, Swedish Defence

Research Agency.

Jullien, A., Dauvergne, M., Cerezo, V., 2014. Environmental assessment of road construction and maintenance policies using LCA. Transportation Research Part D: Transport and Environment 29, 56– 65. https://doi.org/10.1016/j.trd.2014.03.006

Karim, H., Magnusson, R., 2009. Vägbarriärens inverkan på snöplogning. Högskolan Dalarna, Borlänge.

Khoury, P., Grönskog, N., 2015. Tramway of the future : Are tramways with a surface of grass a good option, Student essay. KTH Royal Institute of Technology.

Kliucininkas, L., Matulevicius, J., Martuzevicius, D., 2012. The life cycle assessment of alternative fuel chains for urban buses and trolleybuses. Journal of Environmental Management 99, 98–103. https://doi.org/10.1016/j.jenvman.2012.01.012

Lewis, A.M., Kelly, J.C., Keoleian, G.A., 2014. Vehicle lightweighting vs. electrification: Life cycle energy and GHG emissions results for diverse powertrain vehicles. Applied Energy 126, 13–20. https://doi.org/10.1016/j.apenergy.2014.03.023

(29)

Lindgren, L., 2017. Electrification of city bus traffic : - a simulation study based on data from Linköping.

Matheys, J., Van Autenboer, W., Timmermans, J.-M., Van Mierlo, J., Van den Bossche, P., Maggetto, G., 2007. Influence of functional unit on the life cycle assessment of traction batteries. Int J Life Cycle Assess 12, 191. https://doi.org/10.1065/lca2007.04.322

Nordelöf, A., Messagie, M., Tillman, A.-M., Ljunggren Söderman, M., Van Mierlo, J., 2014. Environmental impacts of hybrid, plug-in hybrid, and battery electric vehicles—what can we learn from life cycle assessment? Int J Life Cycle Assess 19, 1866–1890. https://doi.org/10.1007/s11367-014-0788-0

Nordin, L., 2019. Changes to Road Maintenance and Operations on Electric Roads. Presented at the 3rd Electric Road Systems Conference 2019, Frankfurt am Main.

Notter, D.A., Gauch, M., Widmer, R., Wäger, P., Stamp, A., Zah, R., Althaus, H.-J., 2010. Contribution of Li-Ion Batteries to the Environmental Impact of Electric Vehicles. Environ. Sci. Technol. 44, 6550–6556. https://doi.org/10.1021/es903729a

Olsson, O., 2014. Slide-in Electric Road System Conductive project report, Phase 1.

Pavel, C.C., Thiel, C., Degreif, S., Blagoeva, D., Buchert, M., Schüler, D., Tzimas, E., 2017. Role of substitution in mitigating the supply pressure of rare earths in electric road transport applications. Sustainable Materials and Technologies 12, 62–72. https://doi.org/10.1016/j.susmat.2017.01.003 Peters, J.F., Weil, M., 2018. Providing a common base for life cycle assessments of Li-Ion batteries. Journal of Cleaner Production 171, 704–713. https://doi.org/10.1016/j.jclepro.2017.10.016

Puchalsky, C.M., 2005. Comparison of Emissions from Light Rail Transit and Bus Rapid Transit. Transportation Research Record 1927, 31–37. https://doi.org/10.1177/0361198105192700104 Quinn, J.C., Limb, B.J., Pantic, Z., Barr, P., Zane, R., Bradley, T.H., 2015. Feasibility of wireless power transfer for electrification of transportation: Techno-economics and life cycle assessment, in: 2015 IEEE Conference on Technologies for Sustainability (SusTech). Presented at the 2015 IEEE Conference on Technologies for Sustainability (SusTech), IEEE, Ogden, UT, USA, pp. 245–249. https://doi.org/10.1109/SusTech.2015.7314354

Reza, B., Sadiq, R., Hewage, K., 2014. Emergy-based life cycle assessment (Em-LCA) for

sustainability appraisal of infrastructure systems: a case study on paved roads. Clean Techn Environ Policy 16, 251–266. https://doi.org/10.1007/s10098-013-0615-5

Samaras, C., Meisterling, K., 2008. Life Cycle Assessment of Greenhouse Gas Emissions from Plug-in Hybrid Vehicles: Implications for Policy. Environ. Sci. Technol. 42, 3170–3176.

https://doi.org/10.1021/es702178s

Sandberg, L., 2011. Buss, BRT och spårväg - en jämförelse (No. Rapport 2011:1). WSP Sverige, Stockholm.

Santero, N.J., Masanet, E., Horvath, A., 2011. Life-cycle assessment of pavements. Part I: Critical review. Resources, Conservation and Recycling 55, 801–809.

(30)

30 VTI PM Schulte, J., Ny, H., 2018. Electric Road Systems: Strategic Stepping Stone on the Way towards

Sustainable Freight Transport? Sustainability 10, 1148. https://doi.org/10.3390/su10041148

Schulte, J.P.M., 2015. Smarta steg på väg mot hållbara transporter? : Snabbladdningsinfrastruktur och elvägar ur ett strategiskt livscykelperspektiv.

Singh, B., Strømman, A.H., 2013. Environmental assessment of electrification of road transport in Norway: Scenarios and impacts. Transportation Research Part D: Transport and Environment 25, 106– 111. https://doi.org/10.1016/j.trd.2013.09.002

Stripple, H., 2001. Life Cycle Assessment of Road A Pilot Study for Inventory Analysis, 2nd ed. IVL, Gothenburg.

Stripple, H., Uppenberg, S., 2010. Life cycle assessment of railways and rail transports - Application in environmental product declarations (EPDs) for the Bothnia Line (technical report No. IVL-B-1943). IVL, The Swedish Environmental Research Institute Lt, Stockholm.

Swedish Transport Administration, 2019. Beslut taget om nya demonstratorer for elväg. URL https://www.trafikverket.se/resa-och-trafik/forskning-och-innovation/aktuellt-om-forskning-och-innovation2/2019-04/beslut-taget-om-nya-demonstratorer-for-elvag/ ) (accessed 7.5.19).

Swedish Transport Administration, 2015. Krav för vägars och gators utformning, Publikationsnummer 2015:086.

Vandepaer, L., Cloutier, J., Amor, B., 2017. Environmental impacts of Lithium Metal Polymer and Lithium-ion stationary batteries. Renewable and Sustainable Energy Reviews 78, 46–60.

https://doi.org/10.1016/j.rser.2017.04.057

Wang, T., Lee, I.-S., Kendall, A., Harvey, J., Lee, E.-B., Kim, C., 2012. Life cycle energy consumption and GHG emission from pavement rehabilitation with different rolling resistance. Journal of Cleaner Production 33, 86–96. https://doi.org/10.1016/j.jclepro.2012.05.001

Wu, G., Wu, J., Wei, W., Zhou, Y., Yang, Z., Gao, G., 2018. Characteristics of the Sliding Electric Contact of Pantograph/Contact Wire Systems in Electric Railways. Energies 2018, 13.

(31)

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Life cycle assessments for electric road systems : Review and analysis of LCA studies