Since COVID-19, home office and hybrid work schedules have become popular, with more people acquiring the possibility to take long weekends and work remotely at their flexible time. This benefit has only increased travelers during a holiday season, such as Christmas.
In the US, about 54 million people are believed to have caught flights for this Christmas and New Year. Although the aviation industry is responsible for 12% of CO2 emissions from all transport sources, compared to 74% from road transport, it is still criticized for being complex in adopting renewable energy. Despite advancements in electric vehicles, boats, and trains, where going full electric isn’t an insurmountable engineering barrier, combustible fuel continues to be the only option to fly until now, at least for longer trips.
In October last year, IBA forecasted aviation’s CO2 emissions for 2022 to reach 800 million tonnes —36 % higher than in 2021 and predicted the emissions to match the pre-pandemic peak of 916 million tonnes in 2023. Major players acknowledge the challenge they face to decrease emissions, many of whom are exploring solutions ranging from sustainable aviation fuels (SAF) to hydrogen fuel through the ZEROe Programme.
Sustainable Aviation Fuels (SAF)
The SAF, such as Virent’s BioForm® synthesized aromatic kerosene, is made from plant-based feedstocks. On December 1, 2021, the United Airlines aircraft successfully flew 100 passengers from O’Hare International Airport in Chicago to Washington D.C.’s Reagan National Airport with 500 gallons of 100% SAF in one engine and 500 gallons of conventional jet fuel in another. The experiment proved that there are no operational differences between the two fuels.
However, it was Etihad Airways that became the first airline to participate in World Energy’s net-zero program by displacing approximately 26,000 gallons of petroleum-based jet fuel with equivalent gallons of World Energy’s SAF at Los Angeles International Airport. The result saved emissions of about 250 metric tons of carbon in the routine flight from Washington Dulles to Abu Dhabi during COP27.
Read: COP27: What to expect?
ZEROe Programme
The ZEROe is a hydrogen-powered commercial airliner— if succeeded, will become Airbus’s first ever zero-emission commercial aircraft into service. Airbus previously unveiled their ZEROe aircraft idea in September 2020 and aimed to bring a hydrogen-powered ZEROe to market by 2035.
Hydrogen, however, requires a completely new aircraft design, which comes with obvious design challenges associated with storage. Liquid hydrogen has a lower volumetric density than kerosene and a boiling point of -252.8°C. Therefore, well-insulated cryogenic fuel tanks for liquid hydrogen will be critical for keeping the fuel in a liquid state.
Under the ZEROe Programme, Airbus has been exploring three design concepts, including:
A turbofan design with a range of 2,000+ nautical miles for 120-200 passengers
A turboprop design for shorter-haul journeys for about 100 passengers, and
A blended-wing body (BWB) design for up to 200 passengers.
Each of these aspects represents a unique approach to the zero-emission plane, uncovering different technical pathways and configurations to support the company’s aspiration of being a leader in the decarbonization of the aviation industry.
Who is involved?
Airbus and CFM International are the two major companies involved in this project. Airbus is the leading aircraft manufacturer in the world. CFM International is a joint venture between GE Aviation and Safran that manufactures turbofans for Airbus and Boeing aircraft. CFM International has agreed to modify a combustor, control system, and fuel system, of a GE Passport turbofan to run on hydrogen.
The GE Passport is well suited because of its compact size and low weight, as well as its turbochargers and fuel delivery ability. In November 2022, Airbus announced a plan to repurpose an A380 aircraft with a hydrogen drive train that would drive the GE Passport turbofan by the end of 2026.
Airbus will define the requirements for the hydrogen propulsion system, supervise test flights, and provide the A380 platform for testing the hydrogen combustion engine in cruise mode.
The objective
In the early 1960s, the aviation industry was a relatively expensive mode of transportation that was only accessible to a small percentage of the population— about 100 million travelers worldwide. The number increased to 4.56 billion in 2019. Flying people requires a lot of energy, and that comes with the consequences of a destructive environment. The global aviation industry accounts for approximately 1.9% of global greenhouse gas emissions. If the aviation industry were a nation, it would have an annual GDP of $961.3 billion, placing it 17th in the world.
The International Civil Aviation Organization (ICAO) entailed ambitious targets for reducing the climate impact of the worldwide aviation sector in its 2019 Environment Report. The report reminded the 2010 assembly’s ambition of improving fuel efficiency by 2% annually from 2020 and being net-zero by 2050.
Airbus cited the day the ZEROe concept was launched, as a historic moment for the commercial aviation sector. The concept is envisioned to take a prominent role in perhaps the most important transition this industry has ever seen, having the primary goal of reducing the climate impact of aviation.
Current Status
The Airbus Zero Emissions Development Centre (ZEDC) has opened in Bristol, UK, to test the required technologies. The Filton ZEDC was founded in early 2022 to develop a low-cost cryogenic fuel system for the ZEROe. The work in Filton supplements aids the projects done at existing Airbus ZEDC throughout Europe. Each ZEDC has a distinct focus; in France, Germany, and Spain, the emphasis is on industrialization, with research conducted on fundamental technologies for cryogenic liquid hydrogen tanks.
Airbus is experimenting with two hydrogen systems and procedures at the UK ZEDC: direct-burn and fuel cell. Based on the work done in the coming years, a decision on the fuel system to be used is expected to be made by 2030. An A380 loaded with liquid hydrogen tanks designed at Airbus facilities in France and Germany will be used for the demonstration.
The aviation industry, although being heavily criticized for contributing to global emissions, ZEROe gives us hope that soon in the next 12 years, we can take a flight home for the holidays, and create jobs across the aviation sectors without harming the environment.
Summary
The global aviation industry accounts for 1.9% of greenhouse gas emissions
The aviation industry is unable to rely on electrification, seeking alternative solutions for the decarbonization
Many from the industry are exploring solutions ranging from sustainable aviation fuels (SAF) to hydrogen fuels through ZEROe Programme
