SOUE News Issue 8

The 20% Vehicle

Colin Axon, Co-Deputy Director, James Martin Institute for Carbon and Energy Reduction in Transport and Department of Engineering Science

The hardest energy problem of all is reducing the carbon intensity of our transport system. Transport is overwhelmingly a single fuel system and therefore highly vulnerable, but fossil fuels just have so many advantages - they are cheap, ubiquitous, safe, reliable, and have a very high energy density. So much so, that we're really only looking for the second best solution. If, as a nation, we are to reach the overall 80% carbon reduction target, something dramatic is going to have to happen in the transport sector. If little were to change, then all of the carbon savings will have to be made in the residential and industrial sectors. Transport is the only sector that has continuously increasing emissions and energy demand - from 39.2 MtC1 in 1990, to 43.4 MtC in 2005, accounting for over 25% of UK CO2 output.

Looking ahead from our present position to the broad sunlit uplands of a low carbon economy, we find ourselves staring across a massive chasm with no credible bridges to get us there. Defining these bridges is the main aim and purpose of the newly formed James Martin Institute for Carbon and Energy Reduction in Transport (JMI-CERT). Our new group operates at the interface of the engineering and social sciences and will produce software tools to enable us to accurately estimate CO2, energy, and financial indicators for various technical solutions for the reduction of greenhouse gases emitted by road transport. We will use these tools to propose various feasible scenarios which can advise in the choice of genuinely effective policy instruments. JMI-CERT is joint between the Department of Engineering Science and the Transport Studies Unit (TSU) in the School of Geography and Environment, and funded by the James Martin 21st Century School.

Changes can be brought about by policy and fiscal instruments aimed at smoothing the pathway of implementation for low carbon technologies (perhaps as yet undeveloped). JMI-CERT aims to investigate the interactions of devices and policy in a "whole systems" modelling environment, operating within a system of feedback loops informed by data from real systems (on the road, where possible). The strength of this integrated approach is in exploiting the synergies between technologies, the supporting infrastructure, and the necessity of delivery to the consumer. Society is only at the beginning of developing low carbon vehicles and sustainable transport systems. Not only are there many important questions in fundamental engineering, but also "whole-system" questions which cannot be addressed by traditional means. Effective implementation of new engineering solutions can only be achieved when combined with integrated policy plans. A few small-scale programmes using novel power sources have had local impact, but large-scale deployment has proved too difficult from both engineering and policy viewpoints. Some promising technology has already been squeezed out of the market because the incentives and policy framework were not right. The removal of market barriers to the widespread take-up of lower energy solutions requires not only sustained technological improvements, but also expertly guided legislation and fiscal mechanisms.

There are a great many pundits and technology champions articulately professing what the future will be if their specific technology were taken up. They all promise that we could have equally cheap, but pollution free and environmentally sound mobility. The trouble is that currently no-one really understands how, in a practical engineering sense, to move the transport sector from high carbon usage to low carbon usage, across the chasm. The one thing which is clear is that technology on its own will not be sufficient - we (society) must change our attitudes and behaviour. A central feature of the JMI-CERT programme is to study the effects on markets and policy of using various new technologies to deliver practical low carbon solutions and pathways in the transport sector. The TSU recently completed a project for the Department for Transport on reducing CO2 emissions from UK transport by 60% in 2030. This first step raised many questions requiring considerable long-term research on both technology and policy. There are currently four main types of feasible motive power sources, namely, electrical, fuel cell, hybrid, and high-efficiency IC engines - all at different stages of development and with diverse research, development, and deployment trajectories. The major element missing in the present research effort lies in the integration and inter-operability of these systems. The problems raised by the need to change to a low carbon transport system are very complex - the engineering and policy aspects are our focus. We have recently started work on three main areas, all of which are dependent on one another, in order to get a sense of the overall least cost and most effective combinations of technologies, together with possible implementation pathways:

  1. Life Cycle Assessment (LCA) of alternative technologies in combination and the implications for carbon emissions and infrastructure. This will enable us to develop strategies for the transition from short-term (easy) winners to longer term "solutions". It is the optimal combination of the various technologies and policies to achieve the lowest practical carbon emissions, and a manageable technical switch of the supporting infrastructure, which we need to achieve quickly, in order to cut CO2 soon, and so avoid entirely impractical cuts in 2050;
  2. Understanding the detailed thermodynamic feasibility of these various energy systems and the efficiency of thermal and kinetic energy recovery. It is not possible to recover all waste energy, but the development of on-board systems to recover kinetic and low-grade thermal waste energies is an essential element of reducing CO2 emissions;
  3. Economic models of the technology options, travel demand, energy distribution networks and demand reduction methods. The effect of market mechanisms on technology development and consumer behaviour is a key question in all aspects of low-carbon energy sources. The role of electric cars in exploiting the electrical generation system, including hybrid "plug in" vehicles (not just electric plug-ins) has yet to be fully explored in meaningful detail.

Previous work has limitations such as considering carbon emissions only from new vehicles and not real data from the aging stock, or just looking at the raw financial costs of a technology, or only calculating the sustainability of a small element of a new technology (and then often not in the transport environment). The first attempt at a complete life cycle assessment for a fuel cell powered vehicle was only published in mid-2007, an analysis which the authors recognised had many weaknesses. There has been little previous work in looking at the so-called "embodied energy" of hybrid road vehicles. The current ones use a battery/motor system to give support to a conventional IC engine, but are such systems really a great step forward? Perhaps this is just an incremental advance, which won't lead us to a motive power source independent of oil. What would a truly radical "next generation" hybrid consist of? Should the vehicle be able to handle different fuels simultaneously, is it possible to get around the seemingly intractable hydrogen storage problem? What ratio of vehicle mass to fuel cell capacity might be optimal? What proportion of the vehicle power would be delivered by each component? There are an enormous number of combinations and variables - we suspect (expect?) the answer to be counter-intuitive.

The strategy is to find a good solution which will cut CO2 emissions soon, rather than inch our way to a "best" solution in the indefinite future. This is important as CO2 has a residence time in the atmosphere of 100-150 years, so it is more effective to implement the "nearly" solution early. The only thing which is clear is that the current technological pathways are not going to deliver the 80% reductions in CO2 emissions by 2050. Perhaps the biggest question is understanding how the relative phasing of the transitions between different technologies, the costs and allied policy development could be arranged.

The key elements which must change, and the ones our programme will address, are the energy and power sources. Significant manufacturing developments are required so that economies of scale and lower costs for new low carbon technology can be achieved. These technical developments will emerge from the interface of electrical, mechanical, materials, electronic, information, and chemical engineering, and must be combined with the way they are used to enable the elimination of fossil fuels from the transport sector. Techniques such as dynamic life cycle assessment and exergy analysis can rigorously test combinations of technology, infrastructure, and their related policy options. There is a national need for costed technological alternatives, together with the necessary conditions for their implementation over time (e.g. the supporting energy distribution systems) and the policy measures needed to change patterns of consumption such as pricing measures and fiscal incentives. There is no sector-wide "road-map" which sets out how to achieve a lower carbon future for transport; we currently have a single fuel system and it is likely that the replacement will have similar structural characteristics. The big questions are what will it be, and how is society going to get there?

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