M Page, C Kelly, A Bristow, ITS, University of Leeds, UK



This paper reports the results from a project funded by the Tyndall Centre for Climate Change Research exploring the Hydrogen Energy Economy and its long-term role in reducing greenhouse gas emissions. This paper focuses on fuel consumption from the transport sector to 2050, which is directly related to carbon dioxide emissions. The transport sector accounts for approximately 26% of carbon dioxide emissions in the UK and it is the only sector where emissions are increasing. It is becoming ever more important to develop strategies towards reducing emissions from transport in order to move towards the deep cuts in emissions of 60% by 2050 that are increasingly recognised to be necessary. The development of a hydrogen energy economy has been proposed as a way of reducing greenhouse gas emissions, which will involve the development and widespread adoption of hydrogen as a fuel. This paper explores the degree to which hydrogen powered vehicles could play a major role in the UK transport sector and the potential impact on carbon dioxide emissions under a range of future scenarios to 2050.

There are three key innovative features of this research:

The development of a UK transport model incorporating all motorised modes to be used to estimate the amounts of different types of fuel consumed by the UK transport industry up to 2050 and the resulting emissions.
The use of scenarios to determine potential pathways to 2050 using the UK transport model, a consideration of the practicality of the scenarios, and the potential impact of hydrogen in each.
A drawing out of the policy implications, looking at the feasibility of the pathways and developments and decision points along them.
The UK transport model was designed to be quick and easy to use so as to allow the use of an iterative procedure to develop the pathways for testing the different scenarios. It is based around the four main energy consuming transport modes: road, rail, air and water. The model uses readily accessible and relatively aggregate data sources so as to speed construction and use and is conceptually relatively simple, though maintaining enough functionality to allow the different particular features of the scenarios to be represented.

For rail, air and water sectors, the required inputs are the levels of different types of activity (by different vehicle types) for all the years up to 2050. These were combined with fuel consumption factors to predict total fuel consumed (by fuel type) for every year up to 2050. The road sector is the major source of emissions and so a more sophisticated approach was used. This involved basic modelling of the vehicle fleet (stock turnover for a wide variety of different vehicle types) and the use of sophisticated fuel consumption equations that take into account vehicle speeds on three different road types. Simplified input procedures allow the model to be run in a few seconds (once the relatively simple input data has been prepared).

In developing the potential pathways to 2050 the extent to which hydrogen powered vehicles might be adopted was considered and the scenarios vary in terms of when and how widely hydrogen powered vehicles might penetrate the transport sector. The scenarios used have been widely adopted for forecasting purposes and represent four possible directions of development up to 2050. They are defined around two different dimensions for possible future development, values (which can tend towards either consumerism or community) and governance (regionalisation or globalisation). Divergent development in these two dimensions produces four qualitatively different future scenarios. These comprise: world markets, global sustainability, provincial enterprise and local stewardship. In addition to these scenarios a ?best guess? forecast was also created based on extensions of existing forecasts. A wide range of possible levels of hydrogen in transport emerge as probable under different scenarios, from 5% in world markets to a near total market share under global sustainability.

The model development stage has been completed and the ?best guess? scenario runs undertaken. Despite the complex nature of the road model?s calculations of fuel consumed it actually produces figures for total fuel consumed which agree fairly closely with the known consumption of petrol and diesel fuel in the road transport sector for 2002 (about 5-7% difference). An optimistic ?best guess? assumes that the voluntary agreement with car manufacturers delivers a 25% reduction in emissions from new vehicles by 2008 (from 1995) and that a further agreement is reached for an additional 30% reduction by 2020. The forecast under this scenario suggests that consumption of petrol will fall over the next 25 years and then increases as traffic growth outweighs earlier efficiency gains. Consumption of diesel rises over the entire period because of growth in heavy goods vehicle traffic coupled with the fact that no significant improvement in individual HGV fuel consumption was assumed.

Detailed assumptions based on the other four scenarios have been developed which are being used to provide the quantitative data inputs necessary for the UK transport model from the year 2003 to 2050. These will then be used iteratively to see if they could be made to match the total energy and hydrogen consumption estimates for 2050. The results from the model runs of the various scenarios will be discussed at a key stakeholder meeting in March 2004. The final report of the project will be submitted in April 2004. The results from the ?best guess? and the other scenario runs will be reported and will give an insight into the practicality of the different pathways and the nature and chronology of developments crucial to the endpoints in order to inform the policy debate.


Association for European Transport