Decarbonizing Aviation: Time for hydrogen to take off.
Without some course correction on how we fly today, CO2 emissions from commercial aircraft could triple by 2050 1. Currently accounting for around 2.8% of global CO2 emissions 2, aviation remains one of the harder to abate sectors of transport with no practical alternative mode available for cross global travel.
Aviation is flying toward a cleaner future thanks to hydrogen.
Exhaust emissions while airborne however, is only one side of the story: emissions from the entire airport infrastructure in constant operation mode is the other. Changing how we personally fly – or rather when we choose to fly – is our individual challenge. But changing how planes fly and how the aviation infrastructure operates so as to be less carbon intensive, is a challenge the industry must take on. And it has. Collectively, airlines are targeting net-zero carbon emissions by 2050 3. Hopes of hitting that target could well hinge on hydrogen with its high decarbonizing potential both in the air and on the ground. With its history and scope of expertise, Linde is fully onboard to help.
In the air: Sustainable Aviation Fuels (SAF)
A promising pathway to decarbonizing aviation is to fuel today’s planes with synthetically produced, cleaner alternatives to kerosene – which is refined from fossil fuel feedstock such as crude oil. One production method of a more sustainable aviation fuel (SAF) employs a Power to Liquid (PTL) process, which relies on the supply of a sustainable carbon feedstock (biomass or other unavoidable industrial carbon dioxide sources) and the production of green hydrogen through electrolysis using renewable energy. The carbon and hydrogen are converted to synthesis gas, a mixture of carbon monoxide and hydrogen, which in turn is converted to longer chain hydrocarbons for the production of jet fuel or SAF via the Fischer-Tropsch Process.
Watch the video presented by WE Council and produced by BBC Story Works in collaboration with HyShiFT.
The HyshiFT Consortium
HyshiFT Consortium is a global collective of companies working together to produce Sustainable Aviation Fuel, known as E-Kerosene. The four stakeholders – Linde, Sasol, Enertrag, and Hydregen – are all part of the same story, which is a collaboration to create and use green hydrogen for the production of aviation (jet) fuel. Each company contributes their own expertise within the renewable sector: Enertrag produces renewable power from wind and solar resources, Linde produces green hydrogen and Sasol converts these two inputs into green aviation fuel through its FT reactor.
The type of sustainable aviation fuel that the Consortium will produce is known as PTL- Kerosene. This fuel aims in future to provide the aviation industry with a more sustainable fuel source. The aviation industry – especially long-haul flights – do not currently have feasible carbon neutral energy solutions and producing a sustainable liquid fuel (PtL Kerosene) is therefore the only currently feasible approach. HyshiFT’s target is to produce 50,000 tons/day of PtL Kerosene, which could fuel 2 flights between Germany and South Africa per day.
Creating synergies, harnessing technology
"We can stay at home, or we can find a more sustainable solution."
A project perspective from clean hydrogen expert, Kate Macfarlane
“The majority of SAF fueling today’s planes comes from cooking oils and animal fats, or biomass, such as sugarcane and corn grain. However, such feedstocks are grown on arable land, which could potentially be used to grow food, so feedstock limitation becomes a challenge.
Projects such as HyShiFT provide a scalable solution to produce PtX Kerosene via green Hydrogen and Fischer Tropsch. With the EU and its member states establishing increasingly tightening quotas for SAF blending, PtL kerosene is acknowledged to be an important piece of the decarbonizing strategy going forward. We are proud to bring our years of hydrogen heritage and unrivalled expertise to this collaborative effort to find a solution for more sustainable flight.”
In the air: The pursuit of zero-emission flight
The promise of hydrogen’s zero-carbon emissions is also propelling the development of cleaner alternative propulsion technologies for future aircraft. Most of today’s hydrogen-powered flight concepts use fuel-cells to generate electricity or combust hydrogen in an engine – or both. But while theoretically tried and tested, hydrogen combustion in practice remains a challenge.
Safe and secure hydrogen storage on planes could inspire a complete rethink of aircraft design. Airbus is taking the lead in the development of hydrogen flight with ZEROe.
Liquid hydrogen not only requires cryogenic onboard storage but in amounts that could cover long-haul flights. This leaves planes at a volumetric disadvantage over their terra firma counterparts like trains and automobiles with their refueling infrastructure.
However, this is a challenge industry players are taking on. With its ZEROe programme, Airbus is one of the pioneers in this field and has the ambition to develop the world’s first zero-emission commercial aircraft by 2035, based on hydrogen propulsion. In addition, Airbus is taking an active role in decarbonizing airports, in collaboration with Linde, with the development of Hydrogen Airport Hubs.
On the ground: Hydrogen Hub Airports
Efforts to decarbonize the aviation industry are not limited to reducing emissions from flights. Planes take off and land from the complex supportive ecosystems we know as airports. The facilities themselves need heating and lighting, passenger buses and other airport vehicles need fueled, and energy is needed for all of this. These hubs of activity could become hydrogen hubs – offering a way to achieve climate-neutral operations across the entire value chain.
Hydrogen Hub at Airports (Reproduced with permission from Airbus)
Linde is using its expertise to study the potential for such a hydrogen hub in the city state of Singapore. The two-year study in cooperation with Airbus, Changi Airport Group, and the Civil Aviation Authority of Singapore will examine the infrastructure requirements and supply solutions to support hydrogen-powered aircraft and airport operations at Singapore’s Changi Airport. These requirements include the production, storage and distribution of hydrogen in aircraft ground services, operational equipment and refueling systems.
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Carbon Capture for Use or Storage
Electrolysis for green hydrogen