Diploma thesis deals with use of combustion chamber to drive the electric bus charging unit. Based on the research and analysis of operation economy, a turboexpander with an air pressure tank is selected to drive the charging unit. A thermodynamic design is created for this variant. Based on this design a unit layout is proposed. Layout drawings are created for the proposed layout.

Concern regarding sustainability and climate change is increasing, which is forcing countries world-wide to take action. The Swedish government has set a goal of fossil-free tra_c until 2030. Battery Electric Buses (BEB) might be one of the solutions needed in order to reach this goal. However, currently its prevalence is at an early stage.   The purpose of this study is to investigate how the technological transition towards BEBs in Sweden a_ects the public transport operators (PTOs). Moreover, to investigate how a third party service provider of Fleet Management System (FMS) services can support the PTOs in this transition.   The research has been carried out in co-operation with a PTO and a FMS service provider. The research contributes to their current understanding of how they will be a_ected by the emerging technological transition. This thesis also contributes with new empirical data of the technological transition towards electric vehicles within public bus transport, seen as a Large Technical System. Conceptually it contributes, by exploring how external companies can support the technological transition towards BEBs, with the application of Technological Transitions theory and the Multi Layer Perspective framework.   The methodology used is a case study of the technological transition towards BEBs in Sweden. Data was collected through twelve semi-structured interviews with researchers, PTOs, public transport authorities (PTA), a BEB manufacturer and a FMS-service company. Parallel to this a questionnaire was distributed to the twenty largest PTOs in Sweden. Moreover data was collected from company visits, pilot-project results and internal documentation.   Our findings show that there are thirteen perceived barriers present among the PTOs, in the process of BEB adoption. Six of these barriers relate to component aspects of BEBs, and seven relate to managerial aspects. Perceived barriers linked to component aspects of BEBs are; Variation in solutions and lack of technical standards, the Charging infrastructure, Shorter range or decreased load capacity, Unknown functionality in cold climate, Reliability and Durability. Perceived barriers linked to managerial aspects of BEBs are; Lack of knowledge and experience, Behavioral change, Economy, Maintenance, Ownership of infrastructure and buses, Business models and Varying requirements from PTAs. The barriers FMS-service providers can address are primarily, due to the technological nature of the services, present at niche level. PTOs together with FMS-service providers are encouraged to together strive towards gaining deeper knowledge about the new emerging echnologies. Through this, PTOs could be enabled to overcome the aforementioned barriers. Three reverse salients were also identi_ed, linked to the aforementioned barriers. If the everse salients are assessed, BEB acceptance among PTOs could be increased. The three identi_ed reverse salients are, the battery technology, the charging infrastructure and the contracts/ownership. The co-operation with the commissioning PTO and FMS-service provider has led to valuable access to Swedish public transport actors, and has aided in a deeper understanding of the phenomena. Although, this co-operation might have exposed us to a risk of being influenced.

Biogas is largely utilised as vehicle fuel in public bus transport in Sweden today. This study investigates opportunities and barriers for continued domestic use and production of biogas, in relation to the ongoing electrification of public bus transport. The analysis is based on interviews with actors in public transport and the biogas sector, experts on biogas systems, and representatives for alternative user segments. Three regions were chosen as case-studies for investigations of prospects in public transport, i.e. Stockholm, Västra Götaland and Skåne, though alternative uses were studied from a national perspective. In addition to public transport, considered uses include road transport, sea transport, industries, and electricity and heat production. The study identifies a broad agreement among stakeholders that renewable resources should be implemented where they provide most benefits from a system perspective. Therefore, electric public buses are valued in urban environments, while biogas solutions are found suitable for regional routes. Biogas is further viewed as environmentally beneficial in all user segments except continuous electricity and heat production, where it largely would replace renewable rather than fossil sources. Regarding costs and competitiveness, probable future uses are identified within light and heavy-duty road transport, and in consumer-oriented industries, i.e. the food industry. Economic support in policy instruments is further considered essential for continuous development of the Swedish biogas sector, though current influential instruments, e.g. the tax exemption, are described as short-term and unpredictable. The willingness to pay for the collected societal benefits of biogas further decrease in transitions from public to private consumers, and as biogas solutions simultaneously are linked with limited or uncertain competitiveness in these sectors, risks prevail that such transitions could imply stagnations and declines in biogas use and production, given today’s situation. / Idag används biogas till stor del som drivmedel för bussar inom kollektivtrafik i Sverige. Denna studie undersöker möjligheter och hinder för en fortsatt nationell användning och produktion av biogas, i samband med att bussar inom kollektivtrafiken nu elektrifieras. Analysen är baserad på intervjuer med aktörer inom kollektivtrafiken och biogassektorn, sakkunniga inom biogas, och alternativa användare av biogas. Tre regioner, Stockholm, Västra Götaland och Skåne, valdes som fallstudier för analys av möjligheter för fortsatt användning inom kollektivtrafiken. Alternativa användningar studerades istället ur ett nationellt perspektiv, och inkluderade vägtransporter, sjöfart, industri och el- och värmeproduktion. Studien visar att det råder enighet mellan intervjupersoner att förnybara resurser över lag ska användas där de medför störst samhällsnytta sett till samhället i stort. Inom kollektivtrafiken beskrivs elbussar därför som fördelaktiga i stadsmiljöer, medan biogas ses som lämpligt i regional trafik. Biogas framställs dessutom som miljömässigt fördelaktigt i alla alternativa användningsområden utom kontinuerlig el- och värmeproduktion, eftersom då främst förnybara och inte fossila resurser ersätts. Med hänsyn till kostnader och konkurrenskraft ses lätta och tunga transporter tillsammans med kundnära industrier, t.ex. livsmedelsindustrin, som troliga framtida användningsområden för biogas. Ekonomiskt stöd från styrmedel bedöms vara nödvändigt för en fortsatt utveckling av biogassektorn i Sverige, även om dagens styrmedel, t.ex. skattebefrielsen, beskrivs som kortsiktiga och oförutsägbara. Betalningsviljan för biogasens samlade samhällsnyttor minskar också vid en övergång från offentliga till privata kunder. Eftersom biogas därtill har en begränsad eller osäker konkurrenskraft jämtemot andra alternativ i de privata segmenten, identifierar denna studie risker för stagnation eller nedgång i användning och produktion av biogas vid en eventuell utfasning från den offentliga sektorn, givet dagens situation.

The transition towards electrification in the bus sector is necessary to achieve the global climate goals and has gained significant traction in recent years. However, there are critical challenges associated with this transition, one of them being the absence of excess heat that traditional combustion engines provided to warm the bus cabin. Consequently, a large portion of the battery’s energy is consumed by the heating system. This thesis aims to address this issue by investigating the optimal indoor bus temperature in relation to thermal comfort and energy efficiency for different outdoor climate conditions. Measurements were conducted in Stockholm city during winter conditions and surveys were administered to passengers in order to assess their thermal comfort for different temperatures. The two methods Predicted Mean Vote (PMV-PPD) and Equivalent temperature (Teq) were used to evaluate thermal comfort and provide a basis for a generalized adapted theoretical model. Previous measurements conducted in Ottawa and Dubai were integrated into the analysis to incorporate different outdoor climate conditions. The results showed that the optimal bus temperature for Stockholm was 17.5 and 19.1°C for outside temperatures of 4 and 8 °C respectively. This indicates that the bus temperature can be lowered in relation to the current standard of 21 degrees. The analysis of Ottawa and Dubai, corresponding to outside temperatures of -14 and 39°C, showed that the optimal temperatures were 16.6 and 23.5 degrees respectively. The potential energy saving from reducing the bus temperature by one degree is 0.36 kWh per kilometer. Moreover, the analysis of time dependency in relation to thermal comfort showed that time has no significant impact on bus trips shorter than 15 minutes. The adapted theoretical model for the PMV-PPD method showed the best results when correlating to actual passenger responses. A sensitivity analysis of the measured parameters showed that fixed values and theoretical correlations could be employed for relative humidity, air velocity, and mean radiant temperature without affecting the output, thus reducing the number of sensors needed for future measurements. The clothing insulation values are highly dependent on geographic location and culture, thus it is not possible to develop an all-encompassing theoretical correlation for the clothing insulation. Further measurements are required in different climatic conditions for a more detailed and accurate analysis. / Elektrifieringen av bussektorn är av ytterst vikt för att uppnå de globala klimatmålen och har fått betydande uppmärksamhet de senaste åren. Omställningen till elbussar medför dock vissa utmaningar, bland annat avsaknaden av överskottsvärme, som traditionellt sett kunnat tillhandahållas från förbränningsmotorer för att värma passagerarkabinen. Stora delar av energiåtgången i bussbatterierna går till följd av detta åt att värma passagerarutrymmet. Denna avhandling avser att hantera denna utmaning genom att undersöka den optimal inomhustemperaturen på bussar i förhållande till termisk komfort och energieffektivitet för olika utomhusklimat. Mätningar utfördes i Stockholm stad under vinterklimat och passagerares termiska komfort undersöktes genom enkäter vid olika temperaturintervall. Den termiska komforten utvärderades med hjälp av de två metoderna Predicted Mean Vote (PMVPPD) och Ekvivalent temperatur (Teq), och en allmän anpassad teoretisk metod utvecklades med dessa som grund. Tidigare mätningar genomförda i Ottawa och Dubai integrerades i analysen för att inkludera olika klimatförhållanden. Resultaten visade att den optimala busstemperaturen för Stockholm var 17.5 och 19.1 °C vid utomhustemperaturer på 4 respektive 8 °C. Detta indikerar att busstemperaturen kan sänkas jämfört med den nuvarande standarden på 21 grader. Analysen av Ottawa och Dubai, motsvarande utomhustemperaturer på -14 respektive 39 °C, visade att temperaturer på 16.6 respektive 23.5 grader var optimala för termisk komfort. Den potentiella energibesparingen genom att sänka bussens temperatur med en grad är 0.36 kWh per grad och kilometer. Vidare visade en analys av tidsberoendet att tiden som passagerarna suttit på bussen inte har en avsevärd inverkan på termisk komfort för bussturer under 15 minuter. Den teoretiskt anpassade modellen för PMV-PPD visade bäst korrelation med passagerarsvaren. En känslighetsanalys av de mätta parametrarna visade att fasta värden och teoretiska korrelationer kan användas för relativ fuktighet, vindhastighet och strålningstemperatur utan att påverka slutresultatet markant, vilket tillåter färre sensorer vid framtida mätningar. Beklädnadsnivån är starkt beroende av geografisk plats och kultur, vilket omöjliggör för framtagning av en heltäckande teoretisk korrelation för beklädnadsnivån. Ytterligare mätningar krävs under olika klimatförhållanden för en mer detaljerad och korrekt analys.

Functional and cost effective systems for the full electrification of a bus network are areas of intense research and development. The electrification can be accomplished using different technological solutions, for example using opportunity charging or using an electric road system – ERS. Both opportunity charging and ERS have the potential to be integrated into already existing bus lines. With opportunity charging, the regular dwell time at the end stops is used for the bus to recharge its batteries and with an ERS the bus can charge dynamically along the road. The purpose of this report is to analyze how the existing Alfa- and Beta line at Stockholm Arlanda Airport, in a functional and cost effective way, can be electrified using either opportunity charging or an ERS. The tradeoff between required charging power, battery capacity and the necessity to change the existing running schedule is explained in detail. In addition, the impact on the electrical grid is analyzed based on different load profiles of different charging stations using different power levels. The analysis is based on real data from the Alfa – and Beta line with its existing buses, the electrical grid at Arlanda and data provided by both the leading (electrical) bus manufacturers and the leading charging infrastructure manufacturers.  The outcome of this report suggests that a full electrification of the existing Alfa- and Beta line has the potential to lower CO2-emissions and energy use at a functional and cost effective way.

Air pollution is becoming a major issue in cities across the world, its common cause being the use of fossil fuel combustion engines in both private and collective transport modes. However, alternative technologies, such as biofuels, hybrid and battery electric vehicles, are on the rise. The objective of this thesis is to assess the optimal system’s configuration – a combination of electric traction and the use of biofuels – in a sub-group of Curitiba’s public bus network through the application of two optimisation models – least energy consumption and least cost. Based on these models, total energy, cost and greenhouse gas (GHG) emissions can be calculated for different scenarios to identify the advantages of switching to a low-carbon system. Furthermore, these models can be used by planners and decision makers as a starting point in defining the path towards a cleaner transport system. The results from the energy optimisation indicate that electrification is key in reducing total energy consumption, as this technology is by far the most energy efficient. A 12% reduction could be achieved, when compared to the current scenario (only using diesel B7), and CO2 emissions could be cut by 74%. The cost optimisation shows that electrification is not yet cost competitive compared to other biofuels (biodiesel, bioethanol and biogas), as biodiesel is the only technology selected by the model due to its overall lower cost. Nonetheless, if electricity costs are reduced, which can be achieved, for example, through a reduction or abolition of taxes, electrification becomes an attractive alternative to biofuels. Under these conditions (40% lower electricity price), energy consumption is reduced by 5% and GHG emissions are cut down to 30%. Political will and strategies to decrease the cost of vehicles turn out to be essential in supporting electrification in public transport. Furthermore, adaptations in the time schedules and the organisation of the main transport hubs are required to accommodate battery electric buses.  The number of fast charging stations is usually on a par with the number of bus routes to be electrified. Cost synergies achieved by sharing the cost of a charger among electrified routes with a common start/end stop are crucial to secure the attractiveness of e-mobility. This underlines the importance of analysing infrastructure needs in public transport networks holistically. / A poluição atmosférica é um problema sério em praticamente todas as grandes cidades do mundo, sendo a sua origem mais comum, o uso de combustíveis fósseis em motores de combustão, tanto em veículos de uso privado como em veículos de transporte coletivo. No entanto, tecnologias alternativas, tais como o uso de biocombustíveis, e a utilização de veículos híbridos e elétricos, estão em expansão. Esta tese tem como objectivo avaliar a configuração ideal do sistema, utilizando, num subgrupo da rede de transportes de Curitiba, uma combinação de tração elétrica e de uso de biocombustíveis. Esta avalição é feita através da aplicação de dois modelos de optimização: menor consumo energético e menor custo global. Com base nestes dois modelos, o consumo energético e os custos globais, bem como as emissões de gases de efeito de estufa (GEE), podem ser calculados para os diferentes cenários, de modo a se identificarem as vantagens da transição para um sistema de baixo carbono. Acresce que estes dois modelos podem ser usados por planeadores e decisores, como ponto de partida na definição do caminho a seguir para a transição para um sistema de transporte mais ecológico. Os resultados da otimização do consumo energético, indicam que a eletrificação é fundamental para reduzir o consumo total de energia, pois esta tecnologia é, de longe, a mais eficiente em termos energéticos. Uma redução do consumo total de energia em 12% poderá ser alcançada em relação ao cenário actual (que use apenas o diesel B7) e as emissões de CO2 poderão ser reduzidas em 74%. Na otimização de custos, os resultados mostram que a eletrificação ainda não é competitiva em termos de custos, quando comparada com o uso de biocombustíveis (biodiesel, bioetanol e biogas), uma vez que o biodiesel é a única tecnologia selecionada pelo modelo por ter menores custos associados. No entanto, se os custos da eletricidade forem reduzidos, nomeadamente, através da diminuição ou supressão de impostos, a eletrificação torna-se uma solução atrativa. Numa situação de redução do preço da energia elétrica em 40 %, o consumo de energia é reduzido em 5% e as emissões de GEE são reduzidas para 30%. Vontade política e estratégias destinadas a diminuir o custo dos veículos elétricos, tornam-se essenciais para promover a eletrificação dos transportes públicos. Acresce que, a adaptação dos horários e a organização dos principais terminais de transporte, são necessários para possibilitar a  operacionalidade dos ônibus elétricos. De acordo com os resultados dos dois modelos, o número de estações de recarga rápida é aproximadamente igual ao número de rotas de ônibus a serem eletrificadas. A redução de custos alcançada, partilhando um carregador entre rotas electrificadas com paragens inicial/final comuns, é crucial para garantir a atratividade da mobilidade eléctrica. Isto sublinha a importância dos benefícios de uma análise holística da infrastrutura de recarga nas redes de transporte público coletivo. / Luftföroreningar är en stor utmaning i städer runt om i  världen. Den gemensamma orsaken är användningen av förbränningsmotorer med fossila bränslen i både privata och kollektiva transportsätt. Dock alternativt teknik, såsom biobränslen, hybrid- och batterielektriska fordon, har uppmärksammats och deras användning ökar. Syftet med denna avhandling är att bedöma det optimala systemets konfiguration - en kombination av elektrisk drivkraft  och användningen av biobränslen - i Curitibas allmänna bussnät genom tillämpning av två optimeringsmodeller – en som minimiserar  energiförbrukning och en som minimizerar kostnader. Baserat på dessa modeller, de totala utsläpp och energiförbrukningen, samt deras respektiva kostnader kan beräknas för olika scenarier. På detta sätt  fördelarna med att byta till ett kolfrisystem identifieras. Dessutom kan dessa modeller användas av planerare och beslutsfattare som utgångspunkt för att definiera strategier mot en renare transportsystem. Resultaten från energioptimering indikerar att elektrifiering är nyckeln till att minska  systemets energiförbrukning, eftersom denna teknik är överlägset mest energieffektiv. En minskning på 12% skulle kunna uppnås, jämfört med det utgångsscenariot (endast med diesel B7) och koldioxidutsläppen skulle kunna minska med 74%. Kostnadsoptimeringen visar att elektrifiering ännu inte är kostnadseffektiv jämfört med andra biobränslen (biodiesel, bioetanol och biogas). I detta scenario är biodiesel den enda tekniken som valts av modellen på grund av dess lägre kostnad. Men om elkostnaderna minskas blir elektrifiering ett attraktivt alternativ till biobränslen. Detta skulle kunna uppnås, till exempel, genom skattebefrielse.  Under dessa förutsättningar (40% lägre elpris) minskas energiförbrukningen med 5% och utsläppen minskar med30%. Politisk vilja och strategier för att minska fordonskostnaden visar sig vara avgörande för att stödja elektrifiering av kollektivtrafiken i Curitiba. Dessutom anpassningar av tidstabellerna och organisationen av de viktigaste bytespunkter är nödvändiga. Antalet snabba laddstationer är vanligtvis i linje med antalet busslinjer som ska elektrifieras. Kostnadssynergier uppnås genom att dela kostnaden för en laddare bland elektrifierade linjer med ett gemensamt start / slutstopp. Det är avgörande för att säkerställa e-mobilitetens attraktivitet. Det visar också vikten av att analysera infrastrukturbehoven i kollektivtrafiknätet holistiskt.