Transport, especially high speed, is critical for both economic and social development. In response to mounting environmental concerns, particularly in relation to climate change, the UK Government is seeking to identify the most sustainable transport options for the UK transport network. Key factors for comparison include carbon dioxide (CO2) emissions, capacity, demand and the carbon implications of existing and new infrastructure and technology. These factors will vary on different city pair routes, therefore comparisons need to be made in order to identify the most suitable mode for each journey.
To comparatively analyse by a life cycle assessment (LCA) the carbon implications of air and rail transport options for satisfying future high speed transport demand in the UK.
The UK Committee on Climate Change (2009) have acknowledged that growth in aviation, without improvements in technology and operations, will increase emissions further in this industry, making carbon reduction targets harder to achieve. The Committee’s 2009 report ‘Meeting the UK aviation target – options for reducing emissions to 2050’ made assumptions on future technological development, the uptake of alternative fuels and improved air traffic management and stated that a growth of only 60% in UK air transport could be accommodated for if CO2 emissions in the industry are not to exceed 2005 levels by 2050, a target the UK Government has set.
In order to curb passenger growth and CO2 emissions from UK domestic aviation, the Government are concentrating on a modal shift from air to rail. In March 2010, the Government unveiled plans for a new high speed rail line running initially from London to Birmingham, with possible expansion to the North of England and Scotland (see figure 1). The plans published by a new company, High Speed Two (2010), expect work on the construction to begin in 2015. However, a detailed comparison of the true CO2 intensity of high speed rail transport in the UK has not been established. Previous analysis has concentrated on emissions from operations, ignoring the CO2 intensity of construction and maintenance. Yet a recent study in North America stated that emissions from non-operational activities (such as maintenance and track construction) could be almost double that of operational emissions for rail transport over its entire working life (Chester and Horvath, 2009). With a legally binding climate change target agreed in 2008 to reduce greenhouse gas emissions by 80% (from a 1990 baseline) by 2050, any new transport developments need to have minimal carbon impacts. Table 1 highlights the carbon reduction targets (budgets) set under the 2008 Climate Change Act.
|Budget||Time Period||Carbon Reduction Target (from a 1990 baseline)|
|1||2008 – 2012||22%|
|2||2013 – 2017||28%|
|3||2018 – 2022||34%|
|4||2023 – 2027||50%|
|Ultimate target of 80% reduction (from a 1990 baseline) by 2050|
Table 1. 2008 Climate Change Act Carbon Budgets (DEFRA, 2008)
This research has established the need for a detailed life cycle assessment (LCA) of rail and air transport, taking into account key variables that will determine future CO2 emissions (these include construction, technological changes, and load factors as a result of modal shift).
A life cycle approach has been taken and applied to the chosen city pair routes in the UK, this technique allows for a detailed comparison of a number of different elements which may contribute to significant CO2 emissions throughout the course of the journey for air and rail transport. The results of this will establish which modes are most effective for which journey (in terms of carbon intensity) and also what the ideal scenario may be for the future high speed transport options in terms of meeting the climate change goals and establishing a sustainable high speed transport network. These results will establish whether investing in high speed rail is the right way forward in terms of reducing CO2 emissions in the transport sector, or whether concentrating on other developments would be more beneficial.
Baseline Models: Air and rail transport in the current situation will be analysed on their inherent CO2 output (kg CO2 per available passenger kilometre (apk), this identifies areas of current significant CO2 output. Creating these baseline models allows for future developments to be analysed against the current situation.
Future Models: Future options for air, conventional rail and high speed rail will be analysed by LCA on their apk CO2 output.
The outcome of this analysis will be to identify the most efficient future transport scenario (in terms of reducing CO2 output) for each studied route.
Load Factor Analysis: Once the inherent CO2 outputs for future options in air and rail transport have been identified, an analysis of their performance at varying load factors then needs to be carried out. This analysis allows for recommendations of passenger numbers to be made, in order for a particular mode or technology to be operating efficiently. Several load factor scenarios have been established;
The recommendations from the LCA will highlight the optimal transport modes and developments, in terms of lowering CO2 emissions, for each city pair route analysed. Findings from the load factor analysis will recommend the passenger numbers needed in order to make a particular mode or development efficient in terms of reducing CO2 emissions in line with the Climate Change Act target. Ultimately these findings will assist in the decision making for future transport developments in the UK and in the goal of incorporating high speed transport into a sustainable transport system that meets the needs of the UK population without compromising the targets set under the 2008 Climate Change Act.
This project will contribute to understanding the environmental impacts of air and rail options for high speed transport in the UK, taking into account direct and indirect processes (construction, operation, and infrastructure) of future developments and identify the most practical solution in terms of meeting the UK’s targets for carbon reduction. It will have a lasting impact through providing a strategic toolkit for policy makers.
Chester M. and Horvath A. (2009) Environmental assessment of passenger transport should include infrastructure and supply chains. Environmental Research Letters, 4, Pp. 8
Committee on Climate Change (2009) Meeting the UK aviation target – options for reducing emissions to 2050. The Committee on Climate Change, UK
Department for Environment, Food and Rural Affairs (DEFRA) (2008) Climate Change Act 2008. [Online] Available at: http://www.defra.gov.uk/environment/climatechange/uk/legislation/provisions.htmAccessed 10th September 2009
High Speed Two (2010) High Speed Rail: London to the West Midlands and Beyond. A report to the Government by High Speed Two Limited. Department for Transport, UK