Aviation and aerospace stand at a critical crossroads, with an urgent need to solve the hard-to-abate sector questions. The answers to which have a knock-on effect on the type of supportive infrastructure needed. Currently, aviation is responsible for around 2-3% of global CO2 emissions, and with air travel demand projected to grow, this percentage could soar without significant intervention - particularly as other hard-to-abate sectors decarbonise. The UK and Ireland have both committed to ambitious climate targets, with the UK aiming for net-zero carbon emissions by 2050 and Ireland setting its sights on a 51% reduction in emissions by 2030. Achieving these goals requires a transformation in how we fly, with all aircraft developers, airlines and airports investing in R&D to determine the best route.

One such route, is hydrogen in its various forms. Hydrogen as an alternative fuel offers a compelling solution for several reasons. When combusted, the byproduct of hydrogen is water vapor, making it a zero-emission fuel at the point of use.

Additional advantages for aviation include:

1. Energy Density: Hydrogen has a high energy-to-weight ratio, which is crucial for aviation where weight is a critical factor.
2. Versatility: It can be used in fuel cells to generate electricity or directly combusted in modified jet engines.
3. Sustainability: With CCUS and electrolytic hydrogen production methods, the aviation fuel cycle can become entirely sustainable. However, in the first instance CCUS will be relied on to meet the scale of hydrogen required in the sector and by other off takers.

BOC, a Linde company, is uniquely positioned to pave the path towards a sustainable aviation future. As the UK's largest supplier of hydrogen and having developed hydrogen supportive infrastructure within the transport sector, BOC is capitalising on Linde's vast liquification, including its role in the development of 70% of the world's hydrogen liquefiers.

This expertise is paramount for the sector, because with aviation, the key lies not just in producing hydrogen, but in the liquefaction process. Not widely known, this process requires ten times more liquid nitrogen than hydrogen itself to cool the molecule, presenting a significant challenge and need for supportive industrial gases.

Hydrogen's role in decarbonising aviation is not without challenges. The storage and distribution of hydrogen require significant infrastructure development. Safety concerns, public perception, and regulatory frameworks also need to be addressed. These are all areas where BOC can provide expertise and support with key learnings from adjacent transport sectors.

To transport hydrogen for aviation purposes, support from other industrial gases is essential. BOC’s deep understanding of nitrogen, helium, and other gases is vital in this transition, with these gases playing key roles in the safe and efficient distribution of hydrogen around airfields. For example, helium is required for leak tests given that it has even smaller molecules than hydrogen.

We also provide solutions for the storage and distribution of hydrogen. Our state-of-the-art storage facilities ensure the safe and efficient storage of hydrogen. Moreover, our robust distribution fleet across the country make us a reliable partner in the supply of hydrogen.

Elsewhere, BOC continues to make significant strides in helping to improve decanting times - pumping hydrogen from the BOC tanker into vehicles that take it directly to the aircraft.

In considering the future of sustainable flight, it is often a debated whether SAFs or hydrogen is the better solution. SAFs can be separated into four categories based on the different feedstocks:

1. Biomass-based SAFs are derived from renewable organic materials. These feedstocks include used cooking oil, municipal solid waste (waste from households or businesses), or forestry biomass.
2. Plastic Waste-Based SAFs are derived from plastic waste such as discarded plastic bottles, bags, and containers.
3. CCUS SAFs, whereby CO2 is captured from industrial processes or directly from the air then combined with hydrogen to create synthetic hydrocarbons.
4. eSAF (power-to-liquid), whereby CO2 captured from the air is combined with low carbon hydrogen to create a synthetic JetA1.

With different feedstocks, comes different challenges. For biomass-based SAFs, we do not have the land space required in order to scale, and plastic waste and CCUS based SAFs are derived from fossil fuels. SAF from captured CO2 from the air will be much more energy intensive than producing low carbon hydrogen.

When compared with hydrogen, however, SAFs are considered safer. To address this, Linde and BOC are drawing on their combined hands-on experience, and heritage, underpinned by their culture of safety, to guide the industry towards safe practices.

The shift to hydrogen-powered aviation is a massive undertaking that requires collective efforts from various stakeholders. As part of the Linde group, BOC is already engaging with aircraft manufacturers, airlines, airports, and regulatory bodies to promote the safe hydrogen use in aviation.

The journey to hydrogen-powered aviation is not a short one. But with our technological expertise and commitment to innovation, BOC is ready to rise to this challenge. With this in mind, BOC invites airports, aerospace organisations, and other industry stakeholders to partner– both during the planning stage and for the roll-out of the necessary infrastructure. Together, we can make sustainable flight a reality.