(III) Eco-Friendliness Statistics of Low-Carbon Transportation

i. Energy usage at one-twelfth of that of air travel

Reality has forced people to switch to low-carbon lifestyles, and therefore HSR has come to the fore.

It takes about 5 hours to travel from Beijing South Station to Shanghai Hongqiao Station through the HSR link between the two cities. The CRH380AL train operating on the line uses only one-twelfth of the energy of air travel.

This is a measurement for one type of trains on one line. Another globally accepted metric for comparison is that if the energy consumption index per passenger-km for conventional rail is set at 1.0, then the index would be 1.42 for HSR, 8.2 for automobiles and 7.44 for airplanes.

In terms of energy efficiency, HSR consumes 82% less energy per 100 passenger-km than airplanes and 50% less than coach buses. Moreover, compared to a four-lane highway, HSR also uses 50% less land, requiring just 10% of the land taken by the highway to complete the same unit of transport.

If travel time is not a concern, rail should be our preferred mode of transportation. If we desire both short travel time and ecofriendliness, HSR can offer us both.

Viewed from another perspective, HSR uses secondary energy – electricity, while automobiles and airplanes use non-renewable energy – gasoline or diesel, and this gives HSR an edge.

The converted amounts of emissions of harmful substances such as carbon monoxide for the three means of travel are: 0.902 kg/person for automobiles, 0.109 kg/person for trains, and 635 kg/person for airplanes. These numbers are for comparison with trains on railroads in general, not HSR. CO₂ emissions from HSR are only 6% of those from airplanes and 11% of those from automobiles. Between 2012 and 2019, CO₂ emissions were reduced by 23.2 million tons thanks to the increased number of passengers choosing to travel on HSR as opposed to roads.

Let the numbers speak for themselves. They are actually calling on us to protect the environment, lead a low-carbon life, and embrace HSR!

ii. For high-speed trains, braking generates power

In the HSR sector, speed and energy efficiency are merged into a single goal in design. To go faster, trains should be built as light as possible and have as little aerodynamic drag as possible. If this goal could be achieved, trains would require less energy.

In the auto industry, the best automobiles are not necessarily the most energy efficient, but for HSR, the best trains are always the most eco-friendly.

As a low-carbon mode of transportation, HSR has another extraordinary feature – energy regeneration.

The AC motor installed on the axle of a high-speed train instantly becomes a generator when the train brakes, converting the huge amount of inertial energy generated by the train braking into electrical energy, which is fed back to the grid.

Take the CRH380BL model as an example. Each time it brakes at high speed, about 3,000 megajoules of electrical energy is fed back to the grid. The regenerative braking energy utilization rate of the CRH380AL model is as high as 90%.

Furthermore, high-speed trainsets use LED light sources, and new high-speed trainsets utilize induction light sources, consuming less electricity than conventional trains.

iii. Setting multiple speed grades is environmentally sustainable

According to research, high-speed trains running at 300 km/h consumes only 3.64 kWh of electricity per 100 passenger-km, equivalent to one-twelfth of commercial aircrafts, one-eighth of cars, and one-third of coach buses.

However, another set of operational test data is more noteworthy: high-speed trains consume 9,600 kWh of electricity an hour running at 350 km/h and 4,800 kWh running at 250 km/h.

In other words, running on the same line, a high-speed train travelling at 350 km/h consume twice as much energy as a train going at 250 km/h.

For HSR, speed is of the essence, but speed must be balanced against cost and environmental sustainability.

Thus, China's HSR network is not obsessed with increasing the speed, and 250 km/h has become the most common operating speed. In fact, 350 km/h trains mainly serve busy, high-traffic trunk lines, while 250 km/h trains mostly serve lines with less traffic. Furthermore, all HSR lines accommodate these two speed grades, catering to the different demands of travelers while cutting costs and protecting the environment.

According to an executive with a high-speed train maker, since the start of high-speed train production in China, Chinese manufacturers have built more 250 km/h trains than 350 km/h trains.

When it comes to HSR, the public are more interested in the succession of top speeds reached, while policymakers and engineers are more concerned with the balance between speed and cost-effectiveness. Such rationality has played an invisible but decisive role in the development of China's HSR network and in the choice of technical route.

Thanks to engineers’ unwavering commitment to environmental sustainability, the “Fuxing” series of high-speed trains consume 17% less energy than the previous “Hexie” (Harmony) series, saving about 2,500 kWh of electricity per 1,000 km.

Take the Beijing-Shanghai HSR line as an example. The “Fuxing” high-speed trains running on this line travel at a speed of 350 km/h, consuming 3.8 kWh of electricity per 100 passenger-km or about 50 kWh per person for the entire journey.

HSR is indeed an energy-efficient high-speed mode of transportation.

iv. Construction cost at two-thirds of that of developed countries

HSR is a low-carbon green mode of transportation. In the construction of its HSR network, China adopted the “bridges in lieu of roads” strategy, saving three-fifths of the land needed to lay tracks. Moreover, in the construction of railway stations, various new energy technologies, such as solar photovoltaic power generation and geothermal heat pumps, were employed, greatly reducing operational energy consumption.

China, dubbed an “unstoppable infrastructure builder” for its countless megaprojects, constructs HSR lines more rapidly than any other country. However, projects are never rushed; rather, they are executed based on efficient scheduling and stringent quality standards. Efficiency is achieved with the extensive use of components which are pre-engineered and prefabricated in factories. Efficient planning and optimal resource allocation speed up construction.

Therefore, it is hardly surprising that it took China only three and a half years to build the Beijing-Shanghai HSR line, which set the highest standard for HSR networks worldwide, and five years to complete the entire 2,298-km Beijing-Guangzhou HSR line amid partial commercial operation.

Shorter construction time means lower unit costs. According to a 2019 World Bank report, though bridges and tunnels make up a large proportion of Chinese HSR lines, the construction cost of China's HSR network per km is about two-thirds of that of developed countries, and China's entire HSR network has positive economic returns.