In Southeast Asia, one-world member Malaysia Airlines has completed its first passenger flight powered by a blend of sustainable aviation fuel (SAF). The airline operated a flight from Kuala Lumpur to Singapore, on a Boeing 737-800 which was fuelled with a blend of jet fuel and SAF produced by Finnish company Neste.
SAF is considered the most important way to decarbonise airline operations in the next few decades, before alternatively powered aircraft can be widely deployed in commercial operations. This is why SAF developments deserve attention. Compared to conventional jet fuel, SAF can reduce up to 100% carbon emissions on a lifecycle basis, depending on the SAF technology used. Aircraft today are powered by liquid aviation fuel, made mostly from fossil fuel sources. Yet new fuels have been developed that have the potential to dramatically reduce aviation’s net CO2 emissions. Although supply is currently limited (0.01% of global jet fuel use), sustainable aviation fuels (SAF) are already in use today and take-up is increasing.
Aviation currently accounts for approximately 2-3% of man-made global carbon emissions, but without action, aviation could consume up to 22% of the global carbon budget by 2050. To maintain growth and at the same time address its environmental impact, the wider aviation industry has committed to reducing net aviation carbon emissions to 50% below 2005 levels by 2050.
Sustainable Aviation Fuel is a clean substitute for fossil jet fuels. Rather than being refined from petroleum, SAF is produced from sustainable resources such as waste oils from a biological origin, or non-fossil CO2. It is a so-called drop-in fuel, which means that it can be blended with fossil jet fuel and that the blended fuel requires no special infrastructure or equipment changes. It has the same characteristics and meets the same specifications as fossil jet fuel.
Since the first commercial flight operated by KLM in 2011, more than 150,000 flights were powered by SAF. Commercial aviation currently accounts for approximately 2-3% of manmade global carbon emissions, but without action, aviation could consume up to 22% of the global carbon budget by 2050.
More than 99% of airline emissions and approximately 50% of airport emissions are related to the combustion of jet fuel. Although increased energy efficiency and reduction in energy demand are effective ways to reduce fuel consumption and related greenhouse gas emissions, these improvements do not offer a sole solution to aviation-related emissions.
The aviation industry has a clear vision for its use of SAFs and will adopt only fuels made from feedstocks that can be grown or produced without the risk of unintended environmental and social consequences, such as competition with food production or deforestation.
Several airlines are driving forward the use of SAFs by signing multi-million dollar forward purchasing agreements. Others have invested in start-up support for SAF deployment, and some have promoted SAFs through test flights, research, and investigation of local opportunities. Five airports also have a regular SAF supply: San Francisco, Los Angeles, Oslo, Bergen, and Stockholm.
However, scaling up the use of SAFs to a global market is challenging and requires substantial investment. The industry has called on governments to assist potential SAF suppliers to develop the necessary feedstock and refining systems – at least until the fledgling industry has achieved the necessary critical mass and prices drop thanks to economies of scale.
More than 45 airlines now have experience with SAF, and around 14bn litres of SAF are in forward purchase agreements.
While SAF is widely considered a near-future solution, the industry also has high hopes for hydrogen. This week Central European budget carrier Wizz Air is to explore the potential for hydrogen-powered aircraft operations under an agreement with Airbus. Long touted as a sustainable fuel, hydrogen is now gaining serious traction as a possibility for aviation, and already tests are underway to prove its effectiveness.
Commercial airline jets using hydrogen would emit only water, and initial tests suggest they can be just as fast as traditional planes, carrying more than a hundred passengers per flight over thousands of kilometres. A recent report on the potential of hydrogen-powered aviation said such planes could enter the market as soon as 2035.
In today’s aircraft, wings are where the fuel is stored, and they are in no way large enough to store the hydrogen that would be needed for a long flight. Hydrogen planes of the future could have extra-large fuselages, but more likely they will be what’s called blended wing, in which the planes are shaped like large triangles. This would allow them to store more fuel, but also reduce fuel consumption to make the aircraft aerodynamics even better.
Planes using hydrogen would emit only water, and initial tests suggest they can be just as fast as traditional planes, carrying more than a hundred passengers per flight over thousands of kilometres.
Most of the world’s hydrogen today is produced by reforming methane from natural gas – a fossil fuel – which produces carbon dioxide. Efforts are underway to develop green hydrogen by using an electric current from a renewable source to convert water into oxygen and hydrogen and reduce emissions in its production. If that is possible, along with no emissions from the planes themselves, aviation could become a green form of travel.
There are significant challenges that remain. If Europe were to fully achieve the environmental benefits of hydrogen-power – for example, for air travel, the production of clean – or green – hydrogen needs to be dramatically scaled up. Clean hydrogen is produced from water using an electric current from a renewable source, rather than from fossil fuels. Today only a tiny fraction of hydrogen used in Europe is categorically “clean.”
Hydrogen is a high-potential technology with a specific energy-per-unit mass that is three times higher than traditional jet fuel. Airbus notes that, if generated from renewable energy through electrolysis, given the fact it emits no CO2 emissions, it will enable renewable energy to potentially power large aircraft over long distances but without the undesirable by-product of CO2 emissions.
The reality is this: For now, we are still years away from commercial hydrogen aircraft becoming a reality, though. The refuelling infrastructure doesn’t exist yet and hydrogen is more expensive and difficult to store onboard than kerosene-based fuel. But the journey to a greener, cleaner era of flying is well underway.
Source: Civil Aviation Authority – Qatar