High-Speed Rail
Project Drawdown defines high-speed rail as: track construction for increased use of high-speed rail for intercity travel. This solution replaces other forms of travel, such as by airplane and by internal combustion engine (ICE) car.
High-speed rail (HSR) has experienced significant growth in recent decades, especially in China, whose HSR network grew to almost 20,000 kilometers in a few years. Growth is expected to continue as China and the European Union add to their extensive networks and new countries build their first links. This report seeks to quantify the greenhouse gas emission reductions and costs associated with increased HSR travel.
Project Drawdown takes the definition of the International Railway Union (UIC) [1] for HSR as a railway system where tracks are “…new lines designed for speeds above 250 km/hr and in some cases, upgraded existing lines for speeds up to 220km/hr.” [2] HSR’s most noted competitor—airplanes—emit more greenhouse gases per passenger-kilometer than HSR. [3] Thus, while HSR is a solution to multiple high-emitting modes of transportation, this study focuses on the replacement of air travel specifically.
Methodology
Total Addressable Market [4]
The total addressable market for HSR is defined as the total non-urban travel projected by key sources like the International Energy Agency (IEA) and the International Council on Clean Transportation (ICCT). The current market share [5] of HSR is estimated from UIC and Amtrak data. The data shows that just over 2.4 percent of the global market is provided by HSR on the world’s existing 29,700 kilometers of HSR tracks.
Adoption Scenarios [6]
Projections of HSR adoption are based on announced plans for HSR track construction, which is chiefly done by governments. Using UIC data and other web searches, estimates were collected of total track length under construction and planned, along with estimated completion dates. Total track length estimates amount to 49,000 kilometers.
As HSR has very different travel densities, or usage rates, in different parts of the world, the travel densities for countries with existing HSR were collected, and these values were used to predict the passenger-kilometers for new tracks. [7] For countries without any existing tracks, travel densities of the most similar country or region with HSR tracks were used.
Impacts of increased adoption of high-speed rail from 2020-2050 were generated based on three growth scenarios, which were assessed in comparison to a Reference Scenario where total HSR travel remains fixed at the current levels (2.4 percent of the annual market).
- Plausible Scenario: The potential adoption was determined based on the total announced track construction with the expected completion dates, and the travel densities of each country with an additional 1 percent annual growth rate applied to HSR usage.
- Drawdown Scenario: The same inputs were used as in the Plausible Scenario above, but a 2.5 percent annual growth in the travel density of each country was applied.
- Optimum Scenario: The maximum current travel density on a national network was used to estimate the maximum travel possible worldwide. Japan’s density, highest in the world, was used for the entire world.
Emissions Model
For operating emissions, increased grid electricity use from HSR adoption was included, along with jet fuel emissions for the conventional alternative. Indirect emissions were also included for infrastructure operations.
Financial Model
First costs for HSR were considered as track construction costs. A conservative value of US$36 million per track-kilometer was used, [8] corresponding to one standard deviation above the global average to account for cost overruns of such major public works. [9] For the conventional alternative, runway construction was used as a proxy for the first cost of air travel. This infrastructure cost was estimated to be US$311 million per runway, based on data from different regions around the world. [10] A single runway generates many more passenger-kilometers per year on average than 1 kilometer of HSR track. [11]
Operating costs for HSR and the conventional alternative include operations and maintenance costs of the infrastructure and energy for train motion (grid electricity) and aircraft (jet A1 fuel).
Results
The Plausible Scenario estimates an emissions reduction of 1.52 gigatons of carbon dioxide-equivalent greenhouse gases over the 2020-2050 period. Most emissions reductions will come from Asia due to the extensive HSR growth planned in China. Globally, this is expected to result in an additional US$1.04 trillion in construction costs compared to the conventional alternative, but should save US$368 billion in operating costs. In the Drawdown Scenario, the avoided emissions could be as high as 3.4 gigatons. As a result of the higher usage of the tracks, fewer tracks may need to be built. The Optimum Scenario results in a reduction of 4.8 gigatons of emissions over 2020-2050.
Discussion
Other benefits of HSR not calculated in this model include: reduced road congestion, lower local pollution and noise, and easier and more comfortable travel. As indicated in our results, however, HSR is expensive to build, with higher expenses for higher speeds. Some research points to positive economic effects of HSR, but it is unclear whether these are actually generated by HSR or merely re-distributed to other regions.
A policy of encouraging more usage of existing HSR tracks does make sense, as that improves the solution’s climate and financial impacts, and as the marginal cost of adding more trains is very low. The EU has this policy, and we see many more countries following suit. We also expect increased travel on Chinese lines.
Often transport impact analyses use some sort of choice model, but this is not possible at the global level because of sparse data. Our approach is reasonable since it is grounded in firm construction announcements and existing travel. Due to the high quality of HSR travel, it tends to attract many air travelers on reasonable-length routes, [12] but it also attracts people who would have used cars or conventional rail, or who would not have traveled at all before HSR. We did not model this diversity of alternatives due to the inherent complexity in combining data.
The positive effects of HSR can be maximized by building HSR lines in travel corridors where the train will compete for travelers with higher-polluting travel modes such as airlines and automobiles, and where traffic is already high.
ERRATUM in Book
In the first printing of the book, there was a sign error: the net cost of HSR was “-$1.04 trillion”; this should have been a cost of “$1.04 trillion”.
[1] UIC means “International Railway Union” in French (Union Internationale de Chemins–de-fer).
[2] 250 km/h = 155 mph, 220 km/h = 136 mph
[3] This is generally the case even when infrastructure emissions are included, but depends heavily on the number of people in the HSR train and in the aircraft. Emissions per passenger-kilometer for a full aircraft can be lower than that of an almost empty train. Therefore, increasing travel on existing train services can reduce unit emissions.
[4] For more on the Total Addressable Market for the Transport Sector, click the Sector Summary: Transport link below.
[5] Current adoption is defined as the amount of functional demand supplied by the solution in the base year of study. This study uses 2014 as the base year due to the availability of global adoption data for all Project Drawdown solutions evaluated.
[6] For more on Project Drawdown’s three growth scenarios, click the Scenarios link below. For information on Transport Sector-specific scenarios, click the Sector Summary: Transport link.
[7] This omits numerous factors that affect demand for new HSR lines, but as a first approximation at the global level, it is very useful.
[8] All monetary values are presented in US2014$.
[9] This number includes tracks in China, the USA, Japan, and Europe.
[10] Data from Europe, Africa, the Middle East, Asia, North America, and Latin America was used.
[11] The passenger-kilometers per runway were estimated using an estimated commercial airport count from the Airports Council International, assuming 2 runways per airport. Total air passenger-kilometers were obtained from IEA (2016), Energy Technology Perspectives 2016: Towards Sustainable Urban Energy Systems, available at http://www.iea.org/etp/etp2016/.
[12] The typical distance where HSR can capture a lot of the traveling market is where it can complete the journey in around 3 hours (at an average speed of 220 kilometers per hour, this is just under 660 kilometers, or 410 miles).
