Planes, trains & ships: Hydrogen’s role in clean transport

This article was originally published on 22 October 2020 and updated on 28 September 2022.

When the general public hears about hydrogen, it is usually in reference to fuel cell electric vehicles (FCEVs). While sales of these vehicles are predicted to rise, hydrogen is actually forecast to have a far greater impact on long-haul freight, shipping and public transportation. It could also transform aviation, as the limited range and efficiency of the batteries used in electric vehicles makes them unsuitable for aircraft.

Hydrogen’s potential as an emissions-free energy carrier goes far beyond transport applications, offering the prospect of an alternative to fossil fuels that could help decarbonize hard-to-abate sectors such as heating systems and industrial processes.

Advances in transport represent one of the first steps toward realizing a hydrogen economy.

Public transport

Many parts of the world are already embracing hydrogen-fuelled public transportation. The UK’s first hydrogen-powered train has made test runs on its mainline railways, as part of efforts to phase-out diesel rolling stock. This approach would be just as green but more cost-effective than overhead electrification.

As part of plans to embrace a hydrogen-powered transport sector, the German federal government is funding the procurement of 52 hydrogen buses to operate in the Rostock district. Hydrogen FCEV buses now operate in many European countries, the US, Japan, South Korea and China.

Aviation

The International Energy Agency identifies hydrogen-based synthetic fuels as a potential solution for lowering emissions in aviation.

Electrifying the sector isn’t easy. Batteries are heavy and can compromise an aircraft’s power-to-weight ratio; they also provide limited range. These challenges must be overcome to make electric flight a viable alternative for commercial operators.

Hydrogen-derived biofuels have the potential to allow the aviation sector to fly larger and longer, with no emissions.

One project under consideration in the Netherlands is building a 60 MW electrolyzer powered by North Sea offshore wind farms, to create hydrogen that would be converted to methanol and combined with cooking oil to produce 100,000 tonnes of aviation biofuels per year. If given the green light, phase one of the project is due to be commissioned in 2024.

Shipping and freight

For long-haul freight, either on road or by sea, hydrogen is predicted to play a role both directly, in the form of FCEV trucks, and indirectly, by being converted into ammonia as a shipping fuel.

The UN’s International Maritime Organisation (IMO) has set a target for the international shipping industry to halve its greenhouse gas emissions by 2050. With battery technology currently a viable solution only for short journeys such as ferry crossings, alternative approaches are being sought to decarbonize the sector.

As Mitsubishi Heavy Industries (MHI) Group’s e-book on hydrogen explains, it is expected that the IMO’s emissions targets will drive demand for ammonia as a low-carbon shipping fuel. Ammonia can be made from hydrogen and is a denser gas, providing a potential solution for the shipping of hydrogen in large volumes. If pressurized at room temperature, ammonia becomes a liquid in the same manner as liquefied petroleum gas (LPG).

This means it is relatively easy to design and build new ships to handle either LPG or ammonia. Mitsubishi Shipbuilding has already built a multi-gas carrier capable of holding LPG and ammonia. A concept design has been completed enabling very large gas carriers, initially powered by liquid petroleum gas, to be adapted for future use of ammonia as the main fuel source.

The company is also developing a concept ship — the CO₂L-Blue — capable of transporting liquefied CO₂ from carbon capture facilities, safely and economically. This will make carbon capture possible in places where there may not be any suitable storage sites.

Solutions like these mean the world is already travelling toward a hydrogen economy, which could arrive sooner than you might think.