This report calculates the effect on emissions from building a new high speed rail link that connects two major cities located 500km apart. It assumes that emissions from new vehicles and aircraft in 2025 can be used as a proxy for the emissions during a 50-year investment depreciation period. The emissions from the marginal production of electricity, used by rail and electric vehicles, are estimated to amount on average to 530g per kWh for the entire period. Fuels used by road vehicles are assumed to be on average 80% fossil and 20% renewable (with a 65% carbon efficiency in the latter case). Traffic on the new line after a few years is assumed to consist of 20% journeys diverted from aviation, 20% diverted from cars, 5% from long distance coaches and 30% from pre-existing trains. The remaining 25% is new generated traffic. Under these assumptions the investment would result in a net reduction of carbon dioxide emissions of about 9000t per one million one way journeys. Assuming 10 million single journeys per year, the total reduction would be 90,000t. Supposing the price of carbon is $40 per ton, the socio-economic benefit of the reduction would amount to $3.6 million, which is very little in the context of high speed rail. The sensitivity analysis shows that alternative assumptions do not significantly change the outcome. One may also have to consider the impact on climate change of building the new line. Construction emissions for a line of this length may amount to several million tons of carbon dioxide. While there is no cause to prohibit investment in high speed rail on environmental grounds so long as the carbon gains made in traffic balance the emissions caused during construction, marketing high speed rail as part of a solution to climate change is considered to be clearly wrong. Investment in infrastructure for modal shift should only be considered when traffic volumes are high enough to carry the cost. The principal benefits of high speed rail are time savings, additional capacity and generated traffic. For the covering abstract see ITRD E146823
Abstract