The UK transport carbon model: An integrated life cycle approach to explore low carbon futures
Research highlights
►New strategic transport, energy, emissions and environmental impacts model. ►Tool to develop and analyse full consequences of multiple scenarios of transport policy packages. ►Novel approach to modelling demand for new vehicles by market and technology. ►Model available for use by research community via http://www.ukerc.ac.uk/support/tiki-index.php?page=UK+Transport+Carbon+Model.
Introduction
Ambitious targets for greenhouse gas (GHG) reductions and concerns about energy security require comprehensive policy strategies to achieve those goals. These strategies are likely to involve a multitude of policy measures that will need to be integrated and carefully timed. This is particularly so in the transport sector, which is perceived as the most difficult sector to decarbonise and where there is a growing consensus that we will not achieve a low carbon transport system without a combination of demand management, operational, pricing and technical policy options (CfIT, 2007, Hickman and Banister, 2007). Policy makers often struggle with developing comprehensive strategies aiming to achieve a low carbon transport system, reverting to mostly technological options and assuming that society and preferences will not change. In the UK, for example, national strategy development within central government is mostly informed by techno-economic modelling of the energy system (e.g. using MARKAL, Loulou et al., 2004) and/or the transport system (e.g. using the National Transport Model, DfT, 2005). While these models are good at exploring the near to medium term future based on incremental change and technological evolution, they are not particularly good at modelling the wider set of demand and supply-side policies within a changing society and economy. This paper addresses some of these methodological gaps in scenario modelling by introducing a newly developed strategic transport–energy–environment model called the UK Transport Carbon Model (UKTCM).
Developed under the auspices of the Energy Demand theme of the UK Energy Research Centre (UKERC), the UKTCM is a highly disaggregated, bottom-up model of transport energy use and life cycle carbon emissions in the UK. In a nutshell, the UKTCM provides annual projections of transport supply and demand, for all passenger and freight modes of transport, and calculates the corresponding energy use, life cycle emissions and environmental impacts year-by-year up to 2050. It takes a holistic view of the transport system, built around a set of exogenous scenarios of socio-economic and political developments. The model is technology rich and, in its current version, provides projections of how different technologies evolve over time for more than 600 vehicle technology categories,3 including a wide range of alternative-fuelled vehicles such as more efficient gasoline cars, hybrid electric cars, plug-in hybrid vans, battery electric buses and advanced aircraft. However, the UKTCM is specifically designed to develop future scenarios to explore the full range and potential of not only technological, but fiscal, regulatory and behavioural change transport policy interventions. An example is the recent Energy2050 work of the UK Energy Research Centre where UKTCM played a key role in developing the ‘Lifestyle’ scenarios (Anable et al., submitted for publication, UK Energy Research Centre, 2009).
The paper proceeds as follows: first, a short review presents the context in which the UKTCM has been developed, focusing on carbon reduction analysis and the presence (or lack) of similar strategic models; second, an overview of the modelling approach and methods used is given, including more detail on a couple of key features; third, the model is demonstrated by presenting the results of a reference scenario for the UK transport system up to 2050, followed by the comparison of three alternative single policy scenarios and a policy package; fourth, the limitations of the model are discussed before concluding with a summary of the results, ongoing parallel work and an outlook for future work. For more detail on the modelling methods and data assumptions see the UKTCM Reference Guide v1 (Brand, 2010a). For details on the user interface see the UKTCM User Guide v1 (Brand, 2010b). Both are available to download from the UKERC website (www.ukerc.ac.uk).
Section snippets
Carbon pathways
At the global level, transport currently accounts for nearly 25% of energy related carbon dioxide (CO2) emissions (IEA, 2008). From a 2005 baseline, energy use and related CO2 emissions are expected to increase by more than 50% by 2030 and more than double by 2050 (IEA, 2008). The fastest growth in emissions will likely arise from light-duty vehicles (i.e. passenger cars, small vans, sport utility vehicles), air travel, and road freight (IEA, 2008). In the UK, although economy wide emissions
Model overview and architecture
The UKTCM is designed around (a) a set of quantified scenarios which describe a range of possible external political and socioeconomic developments envisaged up to 2050; (b) a set of single policy options and multiple policy packages that include fiscal, technical, regulatory and demand management measures; (c) four linked models of the transport–energy–environment system and (d) a graphical user interface, to set up and run the model and view key modelling results. Fig. 1 provides an overview
Approach
To assess the likely effects of changes in policy and strategy against some reference situation, a ‘reference scenario’ for the outlook period up to 2050 is required. This reference scenario should not be confused with a ‘business-as-usual’ forecast. It can be defined by the user in many ways, for example based on government projections or alternative images of the future. The reference scenario developed for this research is broadly a projection of transport activity, energy use and emissions
Alternative scenarios
To illustrate the variety of policy scenario analyses that can be handled by UKTCM the results of four alternative ‘what if’ type scenarios are presented here. The illustrative scenarios are (a) a private vehicle fuel duty policy with emphasis on ‘early action’ (FD1), (b) effective speed limit enforcement on motorways and dual carriageways (SPE1), (c) a technology promotion and incentivisation programme that affects consumer preferences, market availability and costs of EV and PHEV cars (EV1),
Conclusions
This paper starts with the premise that there is a lack of integrated scenario modelling capability for research and practice that is appropriate for modelling the wide range of policies needed to decarbonise the transport system. It then aims to fill that gap by presenting a newly developed strategic transport–energy–environment model, the UKTCM, which is complementary to more sophisticated forecasting models (which usually address more specific aspects of the transport–energy–environment
Acknowledgments
This research was funded by the UK Research Councils (Grant no. NERC NE/C513169) as part of the Demand Reduction Theme of the UK Energy Research Centre (UKERC). The authors would like to thank the two anonymous referees for their helpful and constructive comments that have greatly improved the original manuscript.
References (68)
Price elasticities of demand are minus one-half
Economics Letters
(2008)- et al.
A meta-model for passenger and freight transport in Europe
Transport Policy
(2004) - et al.
IEA mobility model (MoMo) and its use in the ETP 2008
Energy Policy
(2009) - et al.
Transport and environment database system (TRENDS): maritime air pollutant emission modelling
Atmospheric Environment
(2005) - et al.
Looking over the horizon: transport and reduced CO2 emissions in the UK by 2030
Transport Policy
(2007) - et al.
Future fuel cell and internal combustion engine automobile technologies: a 25-year life cycle and fleet impact assessment
Energy
(2006) - et al.
Vehicle technology under CO2 constraint: a general equilibrium analysis
Energy Policy
(2006) - et al.
Approaches to correct for double counting in tiered hybrid life cycle inventories
Journal of Cleaner Production
(2009) - et al.
Low-CO2 energy pathways and regional air pollution in Europe
Energy Policy
(2001) Modelling car ownership in Great Britain
Transportation Research Part A: Policy and Practice
(2007)
World transport energy demand modelling : methodology and elasticities
Energy Policy
Assessing policies towards sustainable transport in Europe: an integrated model
Energy Policy
Dynamic modeling of vehicle populations: an engineering approach for emissions calculations
Technological Forecasting and Social Change
Life cycle analysis of vehicles powered by a fuel cell and by internal combustion engine for Canada
Journal of Power Sources
Well-to-Wheels Analysis of Advanced Fuel/Vehicle Systems—A North American Study of Energy Use, Greenhouse Gas Emissions, and Criteria Pollutant Emissions
Report on Policy Requirements and Selected Relevant Models/Methods, TRANS-TOOLS Deliverable 1, Funded by 6th Framework RTD Programme
Meeting carbon budgets—the need for a step change. Progress report to Parliament. Committee on Climate Change
Transport and Climate Change
National Road Traffic Forecasts (Great Britain) 1997
Carbon Pathway Analysis, Full Report
Road Transport Forecasts 2008
Transport Statistics Great Britain
UK Air Passenger Demand and CO2 Forecasts
Vehicle Licensing Statistics: 2008
The Report of the Alternative Fuels Group of the Cleaner Vehicle Task Force
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