In the long term, airplanes will also have to be climate-friendly. Researchers around the world are working on alternative propulsion systems. But how realistic are hydrogen and electric aircraft?
The Germans’ favorite vehicle is the car. There are almost 70 million adults. Almost everyone owns a car, and the number is rising. It’s no wonder that when it comes to the mobility transition, everything revolves around climate-damaging combustion engines. They are responsible for… In order to meet climate targets, greenhouse gas emissions would have to fall massively in the coming years. But the opposite could happen, not only because of the vehicles on the ground, but also in the air.
In no other sector have greenhouse gas emissions increased as significantly within a few decades as in air traffic – by 146 percent from 1990 to 2019. Airplanes are the most climate-damaging means of transport, especially when used for short distances. In 2022, domestic flights in Germany were responsible for 238 million tons of CO₂, while the much-criticized combustion engines produced only 166 million tons, show .
Germans are at least as reluctant to give up flying as they are to give up their cars. Almost all of them took a plane for their vacation last year, so in the future not only cars will have to be electrified, but passenger aircraft will also have to become more sustainable. But the mobility transition in the air is much more difficult than on the ground – for several reasons.
Germany is just starting with climate-friendly flights
At the beginning of the more than 100-year history of aviation, pioneers first tinkered with gas-powered models before the gasoline engine prevailed. Today, climate-friendly models are in demand again. The Canadian airline Air Canada, for example, has 30 in Sweden. In pure battery operation, they can cover a distance of up to 800 kilometers without emissions, depending on the load. The Canadian government wants to use this to better connect remote locations. In sparsely populated countries such as Australia, Canada or Scandinavia, “certain short-haul routes are very lucrative because there is no other infrastructure, especially at certain times of the year,” says Simon Kothe, who organizes and supports projects on sustainable flying at the Fraunhofer Society.
In Germany, the . Otherwise, climate-friendly flight technologies are still a rarity here because the infrastructure is comparatively well developed and regional flights are less necessary than in countries like Canada. Bavaria is considered a hotspot for the development of emission-free aircraft. In Donauwörth, Airbus Helicopters is working on electric helicopters, and in Oberpfaffenhofen, electrically powered flying taxis will be tested from next year. In a laboratory near Munich, a start-up is developing lightweight batteries for aircraft. And in Cottbus, Brandenburg, the federal government is supporting projects at the Chesco research center, which will develop and test hybrid-electric drives from 2025 – “even if they can only be used to operate smaller aircraft at first,” says managing director Heiko Witte.
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In Bremen, the company Evia Aero is working on a sustainable flight network for business travelers. Company boss Florian Kruse says: “Due to the corona pandemic, meetings are often held online. And some companies want their employees to travel distances of less than 500 kilometers by train.” Many are therefore foregoing business trips. There are numerous regional airports that can easily connect business locations. Take Chemnitz, for example: “Great city, 250,000 inhabitants, but unfortunately not connected to the ICE network.” Green planes could fill the gap and transport business people on short routes within a radius of 500 kilometers or more to Munich, Hamburg or the Baltic States in a climate-friendly manner.
Industry experts expect that the first climate-friendly aircraft will be available for German passenger transport from 2035. However, it is unclear how expensive the flight tickets will be, whether the climate-friendly aircraft will be used across the board and how many passengers they will be able to transport. Much also depends on the fuel.
Batteries, hydrogen or more sustainable kerosene – which will prevail?
In theory, the car industry has set the pace with batteries and hydrogen. But the mobility transition in the air is much more complicated. According to the German Aerospace Center, purely battery-powered aircraft can currently travel a maximum of 200 kilometers due to their weight. That would not even be enough for a commuter flight between Hamburg and Bremen. In addition, there would only be room for ten people. To achieve greater range, the weight must be reduced, starting with the interior fittings. Kothe expects that the proportion of lightweight materials will increase in the future. Airbus and Boeing are already increasingly using plastic with a high carbon fiber content in certain aircraft.
In five to ten years, the alternative planes will be able to cover a distance of 500 kilometers and, depending on estimates, transport up to 20 people. A flight from Hamburg to Frankfurt am Main would then be possible. The problem with the charging infrastructure still remains. “So far, the electricity at the airports is only enough for lights and temperature in the terminals,” says industry expert Kruse. His company has therefore already signed contracts with airports across Europe to invest in photovoltaic systems, storage batteries and charging infrastructure. The airports will then sell the surplus electricity to local companies, according to the plan.
Hydrogen has the advantage over batteries that it weighs less. The question remains as to how the chemical substance should be transported and stored. Whether hydrogen will prevail as a fuel in aviation depends on how quickly batteries develop. In both cases, researchers are still working on heat management to prevent fuel cells and batteries from overheating or undercooling.
The third possible propulsion technology is SAF (Sustainable Aviation Fuel). This is a low-carbon alternative to fossil fuels such as crude oil and natural gas. It is made from agricultural waste, biomass and cooking oil. The advantage: the aircraft’s engines could continue to be used. SAF is less climate-friendly than batteries and hydrogen, but is the only alternative to fossil fuels on long-haul flights. “That’s why it’s so important to research all parts, because depending on the size and performance class, all components of the engines will play a role in the future,” says Chesco Managing Director Witte.
Travelling a short distance?
Industry experts in Germany think that this is all going too slowly. “We need to get out of the research and development corner and into reality,” says Kruse. Implementation is often stalled for logistical reasons: New Zealand’s airline Air New Zealand has to halt its operations because new aircraft and sustainable fuel are lacking due to supply bottlenecks. Aircraft manufacturers Airbus and Boeing will also have to keep jets with high kerosene consumption in service longer than planned due to production problems.
It is not yet clear whether the dream of green aviation can be fully realized. At least the development of climate-neutral kerosene and hydrogen is progressing: “In the end, it will depend on the size and performance class of an aircraft, but for long-haul flights we will have to rely on alternative fuels in the foreseeable future to replace fossil fuels. With alternative engines we do not yet achieve the energy density here,” says Witte.
In the foreseeable future, only short-haul flights will be climate-friendly, and industry experts see them as an alternative to car and train journeys. However, they are pessimistic: since the end of the Corona pandemic, short-haul flights within Germany have been in much lower demand. Depending on the estimate, sustainable flights could also become more expensive. Perhaps the climate pioneers in aviation will have to come up with something else to make climate-friendly flights profitable in Germany.
Source: Stern
