A comprehensive and policy-oriented model of the hydrogen vehicle fleet composition, applied to the UK market

Road vehicles play an important role in the UK’s energy systems and are a critical component in reducing the reliance on fossil fuels and mitigating emissions. A dynamic model of light-duty vehicle fleet, based on predator-prey concepts, is presented. This model is designed to be comprehensive but captures the important features of the competition between types of vehicles on the car market. It allows to predict the evolution of the hydrogen based vehicle’s role in the UK’s vehicle fleet. The model allows to forecast effects of policies, hence to inform policy makers. In particular, it is shown that the transition happens only if the hydrogen supply can absorb at least 350,000 new vehicles per year. In addition to this, the model is used to predict the demand for hydrogen for the passenger vehicle fleet for various scenarios. A key finding of the policy-oriented model is that a successful transition to a clean fleet before 2050 is unlikely without policies designed to fully support the supply chain development. It also shows that the amount of hydrogen required to support a full hydrogen based vehicle fleet is currently not economically viable; the needed infrastructure requires yearly investment larger than £2.5 billions. In order to mitigate these costs, the policy focus should shift from hydrogen based vehicles to hybrid vehicles and range extenders in the transport energy system

Determining the role of hydrogen in the future UK's private vehicle fleet using growth and Lotka-Volterra concepts.

This research aimed to explore effective strategies for the UK’s private vehicle fleet to transition to a hydrogen one. The main barrier for hydrogen is the lack of refuelling infrastructure impacting the uptake of hydrogen-based vehicles. Current studies focus on the introduction of hydrogen alone with a pre-determined supply chain or consider the study of one part of the supply chain such as the storage. A computational modelling approach was considered to reflect the private vehicle market based on predator-prey concepts. The Lotka-Volterra model captures the dynamic behaviour between two or more competing species/technologies to simulate the introduction of alternative vehicle types and their impact on current vehicles. The behaviour of the predator-prey model was limited to reflect the private vehicle fleet by developing a first-order growth model representing the growth of conventional vehicles over the last 50 years. By modelling the growth of conventional vehicles, the private vehicle fleet was considered holistically rather than a selected supply chain(s). The implication of this was to overcome the issue of lack of data and insights to forecasting hydrogen and alternative fuels, whilst capturing the mutually interaction between multiple competing vehicle types. A key finding associated with this thesis was the demonstration that the modified Lotka-Volterra model is suitable to represent the dynamic relationship of introducing new and multiple vehicle types into the current private vehicle fleet. The results indicated that the model simplified the current hydrogen infrastructure problem by reducing the number of factors and variables considered, offering a robust alternative modelling tool. This thesis suggests that it is unlikely that the entire private fleet will be displaced by hydrogen vehicles, and the upper limit should be set at 50% of the market. The optimum strategy for the UK is 80:20 in favour of non-fuel cell hybrids and electric vehicles to hydrogen-based ones focusing on a centralised network of stations. It is recommended that the HRS is at least operated at 75% increasing to maximum when necessary, avoiding under-utilisation. The main implications are that stakeholders can plan according to the best-scenario from a holistic view to shape the future of UK’s private fleet