Aircraft engines run on deep frying fat in KLM Test Cell.
Sustainable fuel KLM is experimenting with 100 percent SAF: fuel that does not contain extra CO2 to the atmosphere. It should replace kerosene.
The Test Cell calls KLM one of its industrial halls at Schiphol-Oost. And that sounds a lot smaller than the concrete space actually is. Tens of meters high is the bunker. On one side, the hall is closed with vertical bars made of metal. On the other side hang concentric metal circles in front of a wide chimney.
In this bunker, KLM’s Engineering & Maintenance department tests aircraft engines. At the end of the maintenance that takes place in the nearby halls, the company checks the engines in the Test Cell to ensure their airworthiness. In the concrete ‘wind tunnel’, the air flows from the bars to the circles.
Openwork engine hangs in the hoists. The interior is clearly visible; Pipes and cables run to control equipment. Normally, a test run takes one and a half to two hours, but last month technicians were here for a whole day for a special test.
On 19 January, KLM – with engine manufacturer CFM, a collaboration between the American manufacturer GE and the French Safran, and the Finnish fuel producer Neste – conducted an experiment with an aircraft engine that ran entirely on sustainable fuel based on used cooking oil.
At the moment, more sustainable fuel is added to ordinary kerosene in a limited percentage. KLM now flies 1 percent sustainable aviation fuel (SAF). By 2030, KLM wants to fly worldwide with 10 percent SAF – all for CO2-reduce emissions from flies.
Such a test at 100 percent SAF is special. “A small but important step in the right direction when it comes to making aviation more sustainable,” says KLM.
No extra CO2 into the atmosphere
Those who would fly entirely on SAF reduce their CO2emissions by roughly 75 percent. Depending on the type, the alternative fuel also reduces emissions of nitrogen and sulfur, among other things. The combustion of SAF still releases carbon dioxide, but no additional CO is released2 added to the atmosphere as in the combustion of ordinary kerosene. The more sustainable fuel used by KLM is made on the basis of recycled cooking oil.
For airlines, SAF is currently the most important way to reduce climate impact. The European Commission is also focusing on more sustainable fuel to force aviation to become greener. In Brussels, negotiations are underway on a ‘blending obligation’ for airlines of 6 percent SAF by 2030. The US wants 15 percent, the UK and Japan 10 percent.
A lot of attention is now being paid to SAF, because (cleaner) flying on electricity or hydrogen is far from possible. It is even questionable whether such techniques are ever an alternative to long-haul flights with many passengers. The energy density of electricity and hydrogen is much lower than that of kerosene.
Nevertheless, aviation must become more sustainable. Today, flying is still responsible for 2 to 3 percent of global CO2-emission. This is expected to rise to 20 percent in 2050, because much more flights will be flown in India and China.
Tests such as at KLM and elsewhere are essential in the development of more sustainable flying, says Jasmijn Mansvelder of KLM. “They show that 100 percent more sustainable fuel can be used safely.” Last month, she and her colleague Martijn van Moorselaar led the 100 percent SAF test in KLM’s Test Cell.
Airlines also like SAF because it can be used in existing aircraft and transported through current pipelines. “You want to change as little as possible about the aircraft and the engines to fly on more sustainable fuel,” says Mansvelder. Airlines now order the aircraft that will still be in operation in ten or twenty years’ time.
Other forms of fuel
SAF based on recycled fat, algae and vegetable oils is currently the most produced type. There are (at least) two other forms of SAF on an organic and one on a synthetic basis. You can also make SAF by converting alcohol (from sugar cane and agricultural and forestry residues) into fuel. And in the third type, gas from biomass (household waste, agricultural residues) is converted into liquid fuel via a chemical process with hydrogen.
In the US, corn is grown for fuel production, among other things. Although the EU bans such raw materials for SAF, it has led to fierce criticism of the production of sustainable fuel. SAF is greenwashing, critics say, and production diverts attention from ‘real’ sustainable alternatives. And of the most far-reaching solution to greening: fewer flights.
Not food but fuel? KLM says the company wants to stay away from the ‘food for fuel’ debate and does not buy fuel based on food. Two independent organisations are monitoring this, KLM reports.
Synthetic jet fuel is the fourth type, where CO2 and green hydrogen are converted into liquid fuel. Flying on synthetic kerosene, which is not yet widely available, does not give CO2-emission.
The limited availability of SAF makes for a high price. According to KLM, it is 3 to 3.5 times more expensive than regular kerosene. The price difference will undoubtedly lead to more expensive tickets. KLM already charges a ‘SAF surcharge’ of 2 to 24 euros per ticket. And that’s not the only environmental measure that will make tickets more expensive.
Also the European plan to tax the previously untaxed kerosene and the European pricing of CO2emissions make flying more expensive for consumers.
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KLM’s Test Cell runs aircraft engines on frying oil, February 21, 2023
