Concerns over the environmental impacts of the transport sector have led to the United Kingdom (UK) Government establishing a legally binding commitment of an 80% reduction in greenhouse gas emissions by 2050 (relative to the 1990 baseline) through the Climate Change Act 2008. The decarbonisation of the transport sector by 2050 will substantially contribute towards achieving this target. Technological innovations, therefore, have an important role in supporting policy objectives. One innovation that is being developed for this purpose in the transport sector is an alternative fuel vehicle. While there are several alternative fuel vehicle technologies, the only two with zero tailpipe (exhaust) emissions are battery electric vehicles and hydrogen fuel cell vehicles. Both of these technologies are not yet at a stage in their development where they can successfully compete with conventional fuel vehicles (internal combustion engine vehicles). They face a variety of technological hurdles that include range, performance, cost, and infrastructure. Hydrogen fuel cell vehicles are not commercially available, although battery electric vehicles have been on the commercial market for several years. Uptake of alternative fuel vehicles is occurring at a slower pace than hoped by policy makers and manufacturers. The aim of this thesis is to examine the factors influencing the decision to adopt an alternative fuel vehicle, and is underpinned by Rogers (2003) Diffusion of Innovations theory. The Innovation-Decision Process from this theory posits that an individual must first know about an innovation before forming an attitude about it. Innovativeness is instrumental in determining the knowledge an individual has of an innovation and how early in the diffusion process they are likely to become an adopter. Perceptions of the innovation are influential in forming an attitude towards it. The focus of the research is on Birmingham, the UK s second largest city. The first stage of the research involves establishing the locations of individuals across the city that possess socio-demographic characteristics associated with early adopters of alternative fuel vehicles. This is achieved by applying cluster analysis to Birmingham census data, which enabled the identification of a strong spatial cluster of potential early adopters in the suburb of Sutton Coldfield. In the second stage of the research, a household questionnaire was undertaken with 413 respondents in Sutton Coldfield. The analysis of the questionnaire data firstly involves the verification of the early adopter characteristics from stage one by examining the relationship of these characteristics with innovativeness. Analysis is then undertaken of the level of knowledge and the perceptions that the respondents have of alternative fuel vehicles. The final step in the analysis is an evaluation of the characteristics of current models of electric vehicles and how well aligned they are with the driving needs and vehicle expectations of respondents. The results confirm that the knowledge of alternative fuel vehicles is limited and individual perceptions have led to the development of negative attitudes towards them. Socio-demographic characteristics were significant in influencing these factors. There were 5% (21) of respondents who have previously considered the adoption of an electric vehicle but have not yet done so. There is evidence from the survey of active rejection among a small number of respondents. The reasons largely relate to three problems: purchase price, limited range, and poor infrastructure availability. However, the majority of respondents have passively rejected alternative fuel vehicles, such that they have never given consideration to the adoption of one. This confirms that a concerted effort is required to inform the general public about alternative fuel vehicles. Opportunities for increasing adoption have been identified for policy and marketing, including education and awareness-raising campaigns.

Hydrogen has received significant attention throughout the past decade as the United States focuses on diversifying its energy portfolio to include sources of energy beyond fossil fuels. In a hydrogen economy, the most common use for hydrogen is in fuel cell vehicles. Advancements in on-board storage devices, investment in hydrogen production facilities nation-wide, development of a hydrogen transmission infrastructure, and construction of hydrogen fueling stations are essential to a hydrogen economy. This research proposes a novel underground storage technique to be implemented at a hydrogen fueling station. Three boreholes are drilled into the subsurface, with each borehole consisting of an outer pipe and an inner pipe. Hydrogen gas (H2) is stored in the inner tube, while the outer pipe serves to protect the inner pipe and contain any leaked gas. Three boreholes of varying pressures are necessary to maintain adequate inventory and sufficient pressure while filling vehicles to full tank capacity. The estimated cost for this storage system is $2.58 million. This dollar amount includes drilling and completion costs, steel pipe costs, the cost of a heavy-duty hydrogen compressor, and miscellaneous equipment expenses. Although the proposed design makes use of decades’ worth of experience and technical expertise from the oil and gas industry, there are several challenges—technical, economic, and social—to implementing this storage system. The impact of hydrogen embrittlement and the lack of a hydrogen transmission infrastructure represent the main technical impediments. Borehole H2 storage, as part of a larger hydrogen economy, reveals significant expenses beyond those calculated in the amount above. Costs related to delivering H2 to the filling station, electricity, miscellaneous equipment, and maintenance associated with hydrogen systems must also be considered. Public demand for hydrogen is low for several reasons, and significant misperceptions exist concerning the safety of hydrogen storage. Although the overall life-cycle emissions assessment of hydrogen fuel reveals mediocre results, a hydrogen economy impacts air quality less than current fossil-fuel systems. If and when the U.S. transitions to a hydrogen economy, the borehole storage system described herein is a feasible solution for on-site compressed H2 storage. / text

Les piles à combustibles sont considérées comme une énergie d’avenir, notamment grâce à leur caractère non polluant à l’usage. Cependant, le déploiement de ces solutions à grande échelle est encore conditionné par l’amélioration de leurs performances et surtout de leur durabilité afin de garantir une industrialisation à faible coût. L’application de la pile à combustible au domaine des transports impose en plus un fonctionnement à puissance variable, ce qui complique l’amélioration des performances et de la durabilité. L’approche retenue pour ces travaux consiste en la conception d’une loi de gestion du système qui génère les conditions opératoires optimales à appliquer au stack (pressions, température, courant, stoechiométries) en fonction de la demande en puissance, de l’état de santé de la pile (perte de surface active) et du taux d’humidité actuel. L’optimalité est entendue au sens de l’augmentation du rendement système et de la diminution des dégradations du platine et de la membrane. Cette loi se base sur des modèles de dégradations et de performances d’un système pile à combustible. Cette loi de gestion requiert pour fonctionner les données de l’état de santé de la pile et du taux d’humidité. L’évaluation de l’état de santé de la pile fait déjà l’objet de nombreux travaux de diagnostic. En revanche, le taux d’humidité doit être estimé par un observateur d’état car les capteurs d’humidité ne sont pas fiables pour une application transport. Pour cela, un observateur d’état a été développé pour estimer les humidités relatives dans les canaux du stack et aussi le chargement en eau de la membrane, la quantité d’hydrogène à l’anode ainsi que la saturation d’azote à l’anode. Cette dernière donnée permet de proposer une stratégie de purge pour une architecture dead-end basée sur la saturation d’azote, qui limite les pertes en hydrogène et réduit les dégradations liées à cette architecture. / Fuel cells are considered as a promising source of energy for the future, thanks to their non-polluting aspect. However, the deployment of these solutions on a large scale is still conditioned by the improvement of their performance and especially of their durability in order to guarantee a low cost industrialization. The transport application also imposes a variable power demand, which complicates the improvement of performance and durability. The approach adopted for this work consists of the design of a system management law that generates the optimal operating conditions to be applied to the stack (pressures, temperature, current, stoichiometries) as a function of the power demand, the state of health (active surface loss) and current humidity. Optimality is understood in the sense of increasing system efficiency and decreasing the degradation of the membrane and the platinum dissolution. This law is based on degradation and performance models of a fuel cell system. This management law requires in real time the data of the state of health of the fuel cell and the humidity rate. The assessment of the state of health is already the subject of many diagnostic work. On the other hand, the humidity rate must be estimated by a state observer because the humidity sensors are not reliable for a transport application. Therefore, a state observer was developed to estimate the relative humidities in the stack channels and also the membrane water content, the hydrogen at the anode as well as the nitrogen saturation at the anode. This last data makes it possible to propose a purge strategy for a dead-end architecture, based on nitrogen saturation, which limits the losses in hydrogen and reduces the damage associated with this architecture.