With the ever-increasing demand to reduce emissions in the transport sector, there is a need for a varied approach to the development of zero-emissions future fuels.
Although electrification most certainly has its place in the decarbonisation of the transport sector; it is not suitable for all areas of the sector, most notably in heavy-duty, marine, off-highway and aviation.
Therefore, the need to develop a broad spectrum of zero-emissions future fuels for a wide variety of machines is already underway and in the heavy-duty/off-highway sector, Hydrogen is certainly playing a large role in potentially decarbonising heavy-duty vehicles.
However, designing fuel systems with appropriate engineering controls & establishing appropriate guidelines to enable the safe handling & use of any new fuel is imperative. These systems are required for the safety of those involved from the production of the fuel to the end user. Failure to have correct protocols in place could be disastrous.
In the case of Hydrogen for example a number of its properties make it safer to handle and use than some of the fuels commonly used today. Hydrogen is non-toxic for example and because it is much lighter than air, it dissipates rapidly when it is released, allowing for relatively rapid dispersal of the fuel in case of a leak. (1)
However, some of Hydrogen’s properties do require additional engineering controls to enable its safe use, particularly in how it is stored and contained ready for use.
Hydrogen has a wide range of flammable concentrations in air & lower ignition energy than gasoline or natural gas, which means it can ignite more easily. Consequently, adequate ventilation and leak detection are important elements in the design of safe Hydrogen systems. Furthermore, since H2 burns with a nearly invisible flame, special flame detectors are required. (1)
Another safety & engineering consideration required in designing the use of H2 into a product, is that some metals can become brittle when exposed to Hydrogen. Therefore, selecting appropriate materials is important in the design of safe Hydrogen systems.
Hydrogen production:
Although Hydrogen only produces water as a by-product when it is used as a transport fuel; it is the processing of Hydrogen which still creates debate about its place in decarbonisation programmes as dependant on which process is used, grey and blue Hydrogen still produce carbon dioxide in its processing. The most obvious choice for the transport sector is green Hydrogen.
‘Green’ hydrogen, produced through electrolysis using renewable electricity, offers the largest emissions reductions compared to other forms of hydrogen energy. Scaling it up should be prioritised over ‘blue’ hydrogen – made using natural gas and carbon capture and storage (CCS) – which could lock us into reliance on fossil fuels in decades to come. (2)
Hydrogen storage:
Hydrogen storage is one of the challenging factors to making it more accessible to a wider variety of applications. Hydrogen can be stored physically as either a gas or a liquid or in underground caverns.
Storage of hydrogen as a gas typically requires high-pressure tanks (350–700 bar [5,000–10,000 psi] tank pressure).
Storage of hydrogen as a liquid requires cryogenic temperatures because the boiling point of hydrogen at one atmosphere pressure is −252.8°C. (3)
Salt caverns (underground) storage can store TWh of energy & are created by ‘solution mining’, where water is used to dissolve an underground space in a seam of rock salt, allowing hydrogen to be piped in and out. (4)
Hydrogen Transportation
Transporting Hydrogen poses its own set of logistical challenges.
As we know, Hydrogen can be stored as a gas or liquid. However, the fact that liquid Hydrogen requires cryogenic temperatures of −253°C to keep it stable, means that transporting it in its liquid form involves some considerable engineering challenges.
However, Hydrogen could soon be shipped in traditional oil tankers at ambient temperatures if a Japanese pilot project in Australia proves successful.
Eneos, the largest oil firm in Japan, will launch a demonstration plant in Brisbane next month where a liquid hydrogen carrier, methylcyclohexane (MCH), will be made. (5)
MCH is produced by storing the hydrogen in tanks and then reacting the gas with toluene — a chemical compound (organic) — with the help of synthesizing equipment.
Eneos is working on an electrolyser which turns toluene and water into MCH in one step. Hydrogen will be extracted from the MCH once it reaches its ultimate destination. (5)
Dutch oil and storage company Vopak have recently announced that they are collaborating with Hydrogenious LOHC Technologies on a joint venture for hydrogen storage, supply, and transport utilizing typical liquid-fuel infrastructure in a way similar to that of Eneos. (5)
The German-based venture, dubbed LOHC Logistix, is expected to use Hydrogenious’ liquid organic hydrogen carrier (LOHC), a unique technology based on benzyl toluene that can handle it like a fossil liquid fuel in any existing tanker at ambient pressure and temperature. (5)
As the Hydrogen infrastructure grows, so too does the expectation that it will need to be easily accessible when and where it is needed.
As part of the UK Governments Hydrogen Transportation and Storage Consultation July 22, they had the following vision for Hydrogen gas transportation.
As set out in the Hydrogen Strategy, the UK Governments vision for hydrogen transport from the mid-2030s onwards is for a large, integrated, and resilient hydrogen network with multiple entry and exit points within and across regions and/or nationally, the exact scale is yet to be determined. (6)
A range of pipelines could ultimately contribute to supporting the hydrogen economy including onshore pipelines for hydrogen as a gas, liquid hydrogen, a hydrogen carrier and offshore pipelines as well as vehicular transport. (6)
One way of transporting Hydrogen as a gas is contained in high pressure canisters. Hydrogen is an ultra-light gas that occupies a substantial volume under standard conditions of pressure, i.e., atmospheric pressure. In order to store and transport hydrogen efficiently, this volume must be significantly reduced. (6)
Hydrogen being the lightest gas in the entire Universe means that one litre of this gas weighs only 90 mg under normal atmospheric pressure, which means that it is 11 times lighter than the air we breathe.
Therefore, transporting Hydrogen as a gas via road transport, is not the most efficient way to deliver it. However, Czech company Cylinders Holding have developed a new kind of trailer which enables the transportation of 500 kg H2.
The Cylinders Holding trailer has much higher transport capacity than the current solutions thanks to new innovated pressure vessels and the construction solution of the trailer. The trailer is designed for transport of compressed HYDROGEN at working pressure of 200 bar. The gas is stored in transversely and horizontally placed vessels. (7)
The total volume of all the cylinders is 30 000 litres, which corresponds all the way up to 500 kg of Hydrogen at 200 bar pressure. For maximum safety the stainless-steel piping is welded and consists of 7 sections, each of which has one temperature fuse and pressure valve. (7)
As the Hydrogen economy and infrastructure gains traction in the UK and around the world; the need for constant and consistent Hydrogen production and delivery is evident. With trials such as the Eneos project and trailer developments such as those being brought to market by companies such as Cylinders Holding; the logistical challenges being posed by the transportation of Hydrogen are being addressed, enabling the Hydrogen economy to grow.
Written and cited by Katy Mason for and on behalf of Dolphin N2.
- https://www.energy.gov/eere/fuelcells/safe-use-hydrogen#:~:text=A%20number%20of%20hydrogen’s%20properties,in%20case%20of%20a%20leak.
- https://green-alliance.org.uk/wp-content/uploads/2022/05/Prioritising-hydrogen-use-for-UK-transport.pdf
- https://www.energy.gov/eere/fuelcells/hydrogen-storage#:~:text=Hydrogen%20can%20be%20stored%20physically,pressure%20is%20%E2%88%92252.8%C2%B0C
- https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1011283/UK-Hydrogen-Strategy_web.pdf
- https://www.marineinsight.com/shipping-news/eneos-planning-to-ship-hydrogen-in-oil-tanker/?utm_source=rss&utm_medium=rss&utm_campaign=eneos-planning-to-ship-hydrogen-in-oil-tanker
- https://energies.airliquide.com/resources-planet-hydrogen/how-hydrogen-stored
- https://www.cylinders.cz/en/hydrogen/a-159/
