Purpose: The aim of this paper is to investigate the common understanding of the variety of simplifications in LCA, by reviewing what simplification approaches are used in LCA research, and how these simplifications can be categorised. This may contribute to better sharing of LCA results for decision-making, through more transparent reporting, and with consistent terminology of simplifications in LCA.

Methods: The basis for this study is a systematic literature review of simplification approaches in LCA, including both previously published overviews of categories of LCA simplification approaches and LCA case studies using different simplification approaches. The PRISMA statement protocol (Moher et al., 2009) was used to minimize the risk of bias, increase scientific validity, and provide guidelines for conducting the review.

Results and discussion: The simplification approaches identified were grouped according to the element being simplified. Initially, six simplification approaches were identified based on previous categories. However, not all simplification approaches found in case studies fit into these six previously published simplification categories; these simplification approaches were therefore examined, and four additional categories were identified.The identified simplification categories were mapped and explained in terms of their role in the different stages of the LCA framework. Our results support the idea that simplifications in LCA are most often motivated by a lack of data. Most simplifications target the inventory analysis step, with an aim to reduce the inventory analysis effort.

Conclusions and recommendations: There is a need for a common simplification terminology and reporting standard. Due to the wide variety of purposes, scenarios, and products assessed, it is impossible to devise a one-size-fits-all approach for simplifications. Transparent reporting of simplification approaches used in an LCA study requires that they be described, the motivation for their use be explained, and their influence be evaluated; this will ultimately aid the study's audience in interpreting and comparing the results.

Purpose: Two life cycle assessment (LCA) studies comparing a new low-particulate-matter-emission disc brake and a reference disc brake were presented. The purpose was to identify the difference in potential environmental impacts due to a material change in the new disc brake parts. Additionally, the validity was investigated for the simplification method of omitting identical parts in comparative LCA. This was done by comparing the results between the simplified and the full LCA model.

Methods: The two disc brakes, new disc brake and reference disc brake, were assessed according to the LCA ISO standards. The ReCiPe 2016 Midpoint (hierarchist) impact assessment method was chosen. Simplifying a comparative LCA is possible, all identical parts can be omitted, and only the ones that differ need to be assessed. In this paper, this simplification was called comparative LCA with an omission of identical parts.

Results and discussion: The comparative impacts were analysed over seventeen impact categories. The new disc brake alternative used more resources during the manufacture of one disc compared to the reference disc brake alternative. The shorter life length of the reference disc demanded a higher number of spare part discs to fulfil the same functional unit, but this impact was reduced due to material recycling. The new disc brake impacts were connected primarily to the coating and secondly to the pad manufacture and materials. The validity of the simplification method was investigated by comparing the results of the two LCA models. The impact differences were identical independent of the LCA model, and the same significant impact categories could be identified. Hence, the purpose of the study could be fulfilled, and the simplification was valid.

Conclusions: Both LCA models, simplified and full, revealed that the new disc brake had limited environmental advantages. The omission of identical parts made it more challenging to determine if an impact was significant or insignificant. The simplification seemed to be reasonable.

Road transport contributes to approximately one quarter of all EU greenhouse gas emissions and is the leading cause of air pollution in cities. There are significant measures aimed at the reduction of use phase environmental impacts; in the EU, these strategies focus on the decarbonisation of road transport, such as through the prioritization of low- and zero-emission vehicles. Electric vehicles are seen as one of the primary measures for reducing road transport impacts. However, the introduction of new technology includes new challenges throughout the vehicle life cycle, such as the need for critical raw materials, high-energy manufacturing, charging electricity, and waste management; this, in turn, leads to a risk of impact shifts between life cycle phases and impact categories.

Life Cycle Assessment (LCA) is one way to analyse environmental impacts. Applying LCA and life cycle thinking in research and industry allows for the detection of impact shifts and environmental sub-optimisation. A full LCA study is demanding in terms of both data collection efforts and user expertise requirements. The need to simplify the process and results of an assessment in order to support decision-making was identified in the early days of LCA development.

There are numerous simplification approaches in LCA. Previously, the most prominent simplification terms were screening and streamlined LCA; now, a multitude of names and approaches have emerged. There is no consensus in the LCA community about LCA simplifications. In some cases, the line between what should be considered an LCA, simplified LCA or neither is fuzzy. The haphazard application of simplifications in LCA studies undermines the transparency and confidence in results.

The aim of this thesis is to use the life cycle perspective guided by simplified LCA approaches to increase our understanding of the risk of impact shifts, resulting from measures to reduce vehicle environmental impacts. Four appended publications present five LCA studies of road vehicles. All appended studies are simplified using different approaches. The studies examine different impact reduction measures such as changing drivetrains, reducing particulate emissions from braking, and the scrapping of old vehicles. A fifth publication is a literature review that explores the common understanding of simplifications used in published LCA studies. The review identifies and investigates the types of simplifications used and discusses how these might be categorised.

The appended LCA studies examine both impact shifts from one life cycle phase to another and between impact categories. It is difficult to determine whether a decrease in a life cycle phase or impact category could offset an increase in another and, therefore, to be able to determine if an impact shift is an acceptable compromise. New smart materials are expected to solve many environmental impact issues; however, there are risks associated with insufficient life cycle inventory data, limitations in knowledge about potential environmental impacts, and inefficient regulations covering new materials.

The analysis of simplification approaches and case studies indicates that most simplifications are motivated by the lack of primary data. Additionally, study findings strengthen concerns about the significant inconsistency in LCA simplification terminology and how well approaches are described in individual studies. There is a need for a common simplification terminology and reporting standard. Due to the wide variety of purposes, scenarios, and products assessed, it is impossible to devise a one-size-fits-all approach for simplifications, especially if the aim is to identify potential impact shifts.

Vägtransporter orsakar ungefär en fjärdedel av EUs totala utsläpp av växthusgaser och är den ledande orsaken till luftföroreningar i städer. Betydande åtgärder syftar till att minska användningsfasens miljöpåverkan. EUs strategier fokuserar på att minska vägtransporters koldioxidutsläpp, t.ex. genom att prioritera fordon med låga eller inga användning-utsläpp. Elektriska fordon ses som en av de främsta åtgärderna för att minska miljöpåverkan från vägtransport. Dock innebär introduktionen av ny teknik nya utmaningar längs fordonets livscykel, t.ex. behov av kritiska råmaterial, högenergiproduktion, ökad el-behov vid laddning och avfallshantering. Det finns en risk för förskjutning av miljöpåverkan mellan livscykelfaser och påverkanskategorier.

Livscykelanalys (LCA) är ett sätt att analysera miljöpåverkan. Möjligheten att upptäcka förskjutning av miljöpåverkan och ineffektiva åtgärder för miljön är en anledning till att tillämpa LCA och livscykeltänkande inom forskning och industri. En fullständig LCA-studie kräver både betydande datainsamlingsinsatser och krav på användarexpertis. Behovet av att förenkla processen och utvärderingsresultaten för att stödja beslut identifierades redan tidigt under utvecklingen av LCA.

Det finns en betydande mängd av LCA förenklingar. De mest framträdande förenklingstillvägagångssätten var tidigare ”screening” och ”streamlined” LCA, dessutom har en mängd andra namn och tillvägagångssätt dykt upp. Det finns ingen konsensus inom LCA-världen om hanteringen av LCA förenklingar. I vissa fall är gränsen luddig mellan vad som ska betraktas som en LCA, förenklad LCA och ingendera. Godtycklig tillämpning av förenklingar i LCA-studier undergräver transparensen och förtroendet för resultaten.

Syftet med denna avhandling är att öka förståelsen för risken för förskjutning av miljöpåverkan, vid åtgärder för att minska fordonens påverkan, genom att använda livscykelperspektivet stödd av förenklad LCA. De fyra publikationerna inkluderar fem LCA-studier av vägfordon och fordonskomponenter. Alla fem studierna är förenklade genom olika tillvägagångssätt. Studierna undersöker olika miljöåtgärder så som att byta drivlina, minska partikelutsläpp vid bromsning och skrotning av gamla fordon. En femte publikation undersöker också den gemensamma förståelsen för LCA förenklingar, genom en litteraturöversikt av publicerade LCA-studier. Litteraturöversikten identifierade och undersökte vilka förenklingar som används och hur dessa skulle kunna kategoriseras.

De inkluderade LCA-studierna exemplifierade både förskjutning av miljöpåverkan mellan livscykelfaser och påverkanskategorier. Det är svårt att avgöra om en minskning i en livscykelfas eller påverkanskategori kan kompensera för en ökning i en annan. Detta betyder att det är komplicerat att kunna avgöra om en förskjutning av miljöpåverkan är en acceptabel kompromiss. Nya smarta material förväntas vara lösningen för många miljöproblem. Det finns emellertid risker med otillräcklig LCI-data, kunskapsbegränsningar angående potentiella miljökonsekvenser och ineffektiva regler gällande nya material.

Analysen av förenklingstillvägagångssätt och fallstudier indikerade att de flesta förenklingar styrdes av brist på primärdata. Dessutom stärktes anledningen till oro gällande den betydande inkonsekvens i LCA-förenklingsterminologin och hur väl tillvägagångssätten beskrivs i enskilda studier. Det finns ett behov av en gemensam terminologi och rapporteringsstandard för LCA förenklingstillvägagångssätt. På grund av studiers varierande syften, scenarier och analyserade produkter är det omöjligt att utforma ett generellt tillvägagångssätt för alla LCA förenklingar, särskilt om syftet är att identifiera potentiella förskjutningar av miljöpåverkan.

Transport of goods and people is increasing and causing strains on the environment. Road vehicles emit exhaust and non-exhaust emissions. One significant contributor to non-exhaust emissions is particulates generated through wear from braking. The particulates originate from the contact surfaces of the pad and the disc. Particulate emission is a known issue with considerable impacts on plant, animal, and human health. In the EU Horizon 2020 LOWBRASYS (a LOW environmental impact BRAke SYStem) project (LOWBRASYS, 2017), one of the objectives was to design a novel disc brake that reduces particulate generation during braking. One of the results is a novel disc brake with disc and pad-materials that indicate a significant decrease in particulate formation during use. This is accomplished by changing the materials of the contact pair regarding composition and coatings (Wahlström, Lyu, Matjeka, & Söderberg, 2017). Materials used in the disc brakes cause environmental impacts during their life cycle. Some parts and processes need for example critical raw materials such as tungsten, cobalt, and more (European Commission, 2017). This paper evaluates a material selection tool with an environmental perspective for product developers called Eco Audit (Ashby et al. 2008). This tool is featured in the CES Edu Pack software provided by Granta Design, Cambridge University (Granta 2018). The purpose of this study is to evaluate if the Eco Audit tool can provide a fast and valid impact assessment from an LCA perspective. Results of the Eco Audit compared to the SimaPro results indicate that it is possible to make valid conclusions. The validity of the tool is connected to the purpose of the study. If the purpose is to identify critical life cycle phases and environmental impacts, then the tool can accurately aid the user. It could potentially be difficult to make valid conclusions when assessing a product with more complex processes or advanced materials. The tool's strengths are the simplicity and easy accessibility for any user. The trade-off is precision, robustness, and representativeness of the target. 

The development of cyber-physical systems (CPS) requires various engineering disciplines, artifacts, and areas of expertise to collaborate. Powerful software tools are used during this development process, but while successful in one individual discipline, it is often challenging to integrate with other tools. Several studies have been done on integration solutions for these toolchains. However, the possibility of including the sustainability concept to the interoperability strategies is rarely studied. This paper discusses an approach to include sustainability aspects while improving the interoperability of toolchains in CPS manufacturing. To this end, an automobile manufacturing process has been studied as a use case, and relevant sustainability metrics for each stage of the process are identified. Life cycle sustainability assessment methodology is used to identify the sustainability metrics, and the use case is employed to exemplify how some of these metrics can be integrated with interoperable toolchains to illustrate the applicability of the approach.

Conventionally the use phase of a road vehicle contributes to more than 70% of the total environmental impact in terms of energy use or emissions of greenhouse gases. This figure is no longer valid concerning electric vehicles and a shift to other life cycle stages and impacts is expected and should be re-evaluated. The goal of this study is to assess the environmental performance of two prototype vehicle drivetrains; an internal combustion engine and an electric motor, from a life cycle perspective. The assessment is performed in a qualitative manner using the Environmentally Responsible Product Assessment (ERPA) matrix. The two vehicles in this study have similar car body construction, providing an excellent opportunity to highlight the significance of material differences in their drivetrains. The internal combustion vehicle demonstrated a better environmental performance in three out of five lifecycle stages (pre-manufacture, product manufacture, and disposal). In all of these stages, the impact of the electric vehicle is determined by the burden of the materials needed for this technology such as rare earth elements (REE) and by the lack of recycling possibilities. The study demonstrated a need to close the material cycle when it comes to Critical Raw Materials (CRM) such as REE which can only be achieved when the technology but also the incentives for material recovery are provided, i.e. by promoting the development of cost-efficient recycling technologies. Moreover, the need for relevant metrics and assessment indicators is demonstrated to be able to compare the two technologies fairly.

Conventionally the use phase of a road vehicle contributes to more than 70% of the total environmental impact in terms of energy use or emissions of greenhouse gases. This figure is no longer valid concerning electric vehicles and a shift to other life cycle stages and impacts is expected and should be revaluated. The goal of this study is to assess the environmental performance of two prototype vehicle drivetrains; an internal combustion engine and an electric motor, from a life cycle perspective. The assessment is performed in a qualitative manner using the Environmentally Responsible Product Assessment (ERPA) matrix. Having a similar car body construction, the two vehicles provided excellent opportunities to highlight the significance of material differences in their drivetrains. The internal combustion vehicle demonstrated a better environmental performance in three out of five lifecycle stages (pre-manufacture, product manufacture, and disposal). In all of these stages the impact of the electric vehicle is determined by the burden of the materials needed for this technology such as rare earth elements (REE) and the lack of recycling possibilities. The study demonstrated a need to close the material cycle when it comes to Critical Raw Materials (CRM) such as REE which can only be achieved when the technology but also the incentives for material recovery are provided i.e. by promoting the development of cost efficient recycling technologies. Moreover, the need for relevant metrics and assessment indicators is demonstrated in order to be able to fairly compare the two technologies.

Vehicles are generally viewed as having their major environmental impact in the use phase because of combustion emissions. New technology can significantly decrease use emissions. These advantages suggest a rise in alternative vehicle drivetrains, e.g. electrical motors as well as a decrease of fossil fuel engines. It is of importance to consider what impact this technical shift might have in a lifecycle perspective. New technology requires specialised materials which in turn have substantial impacts during raw material extraction, manufacturing, and end of life. This means that the utilised materials may affect the total life cycle impact of a product. The impact can shift to other life phases and additionally give rise to impacts other than the frequently used energy consumption and climate change. The aim of this thesis is to understand how system boundaries effect environmental impact assessment. Potential life cycle assessment issues are investigated through studies of vehicle environmental impacts in different lifecycle phases and varying system boundaries. These issues are approached through several tools: LCA, Environmentally Responsible Product Assessment (ERPA), and Material Hygiene (MH). Three publications are appended to this thesis. Publication A compares two different disposal scenarios for end of life vehicles in Sweden. Publication B compares complete life cycle impacts of two dissimilar drivetrains in similar vehicles. Publication C investigates potential benefits of a concept sea vessel by comparing it with cargo transport by trucks. To fairly compare vehicles, with different drivetrain technology, it is not advisable to apply assessment that is limited to studying the use phase. Neither is it reliable to limit impact inventory to only energy use and CO₂ emissions. The consequences of a narrow system-boarder are difficult to keep track of. To avoid sub-optimising and minimise risk of unawareness of trade-offs life cycle perspective is essential.

Alongside the economic growth demands for further use of resources increase as well. As a result of this transportation of industrial products all over the world will also increase, in particular through shipping. In this study a new innovative concept for transport of cargo, the CargoXpress vessel, is presented and analysed over the life cycle in terms of costs and environmental effects. In the life cycle cost analysis the influence of future price scenarios for LNG-fuel and structural material is investigated through sensitivity analysis. For the environmental study life cycle assessment is used according to ISO 14044:2006. In direct comparative analysis the environmental impacts and costs over the life cycle of the new vessel is compared to road transport by truck. Then also analysis is made by selecting different existing transport scenarios were the new vessel is compared to road transports. The results from both cost and environmental analysis clearly present benefits for transporting goods with the CargoXpress vessel. Regarding the cost several factors in combination plays an important role for the outcome as initial investment cost, price development of fuel and interest rate. For the environmental analysis the innovative vessel is shown to be the preferable alternative.