Climate Friendly Long Range Aircraft


sustainable AIRCRAFT

We need to change the way we fly

The rapid pace of change in aviation and ambitious climate protection targets call for the technical improvement of aircraft. Since long-range flights account for the majority of pollutant emissions in aviation, more environmentally friendly alternatives must be found for aircraft of this category.

More than 50 % of CO2 emissions caused by air travel can be traced back to long-range flights.

While there are several concepts by large and small aircraft manufacturers on how to build climate friendly short-range aircraft, there is a lack of mature concepts for the long-range sector.

Reducing contrails and making aircraft fuels CO2 neutral will help to limit global warming. 

This is why we propose the following solution:


Designing the First Climate-Friendly Wide Body Aircraft

Fuel alternatives were to be compared in detail: To select the best suiting fuel for a future long range-aircraft, that meets the expected market demand in 2040. The design of this aircraft can be evaluated in comparison with today’s state-of-the-art long-range aircraft.

Liquid methane, stored at cryogenic temperatures, is a very promising fuel for future long-range aircraft due to its minimal climate impact and its easy distribution via the existing natural gas infrastructure. 

This aircraft design can be operated not only with Green Methane, but as well with alternative back-up fuels (methane or kerosene), which eases the transition period until a worldwide Green Methane supply is assured

This wide body long-range aircraft is based on today’s well-understood aircraft design concepts.

280 passengers

9,000 km

Maximum Take-Off Mass: 224 tons

Wingspan 65,0 m

Length 63,3 m

Cruise Speed: Mach 0.85

Insulated fuselage tanks, that are separated from the pressurized passenger cabin.

Slim and efficient wing design.

The Green Aircraft predicts a reduced climate impact.

AIrcraft design

Outline of A330 (black) vs.
Green Aircraft

The architecture of the Green Aircraft is different from kerosene-powered aircraft. The cryogenic tanks are preferably placed inside the fuselage, which inevitably reduces the volume available for airfreight. But, the wing not being used as a primary fuel tank allows more efficient wing design opportunities. 

The performance evaluation of the Green Airliner predicts a reduced climate impact compared to a state-of-the-art Airbus A330neo:
When the Green Airliner is fueled with today’s fossil methane and when using current engine types, the CO2 emissions are reduced by 36 %, compared to an Airbus A330neo on kerosene fuel.
Switching from fossil methane to green methane eliminates net CO2 emissions entirely.

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Why Green Methane

Green Liquid Methane comes with real benefits.

Green Methane is CO2 neutral.
Its combustion emits the amount of CO2, that it has taken up during its production.

Green Methane reduces radiation effect of contrail- and cloud-formation. Interestingly, this is of much greater importance than CO2-neutrality!

Green Methane is made from water + CO2 + green energy.

Aircraft fuel

The advantages of Green Methane over Green Hydrogen and Synthetic Kerosene

Climate effects from air travel can be attributed by
30% to CO2 emission
60% to contrail and cirrus cloud formation.
Thus, an aircraft fuel being CO2 neutral only, covers just these 30%. That is not sufficient to reach our climate goals. It is the major drawback with (expensive and rare) e-kerosene (SAF).

Hydrogen fuel is politically very much „en vogue“. Research is funded by governments.  Airbus Industries published hydrogen aircraft studies. However, Green Methane long-range aviation fuels provides substantial advantages:

Green Methane tanks are 3x smaller

…than hydrogen tanks. Green Methane tanks fit into today’s aircraft fuselages. Retrofit of the actual fleet needs to be evaluated. This could allow a quicker transition to a climate friendly intercontinental aviation.

Green Methane is safer to handle, less volatile

Liquid hydrogen needs to be stored at extremely low temperatures (-250 °C) in large aircraft tanks. Leaking of super-cold hydrogen may lead to brittle fractures, which could critically weaken the aircraft structure.
Green Methane storage temperature is higher (-170 °C) and therefore less problematic.

Hydrogen H₂ molecules are very small. H₂ tends to diffuse through seals and fittings. On the other hand, Green Methane may use today’s infrastructure. It can be distributed by ship or pumped through natural gas pipelines. Storing is possible in today’s gas tanks.

During generation, distribution, storage and combustion, 
unburned methane may leak. It shows a pronounced radiative forcing effect and should not be released to the atmosphere („methane leakage“). This is a serious threat, that requires to be addressed. More efforts are needed to minimize worldwide methane leakage! First agreements on this have been reached on the COP26 Glasgow Conference.

Download our detailed evaluation on future long range aircraft fuels here: Fuel Selection


Is Methane Aircraft fuel all new?

No, for narrow-body aircraft: More than 30 years ago, gas powered TU-155 flew over Russia.

Yes. Long-range wide-body aircraft on methane fuel are a challenge to be taken up now.


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METHQUEST project shows how to produce and use Green Methane


Green Methane supply needs to be generated in sufficient quantities.
A green Power-to-Gas industry is a key element to a sustainable energy supply.

MethQuest and other R&D projects develop the necessary technologies and processes for Green Methane mass production. Direct Air Capture (of CO2) ventures start to operate in countries, like Norway.

Intermediate solution

Fossil methane is readily available today and may serve as intermediate aviation fuel.

In air travel, fossil methane causes ca 50% less greenhouse effect (from contrails & cirrus clouds) compared to today’s kerosene.

Can you imagine? Synthetic kerosene (SAF) is less climate friendly than fossil methane!

„Driving the energy revolution with renewable methane“ The MethQuest research project is about creating new processes for generating renewable gas fuels and progressing existing technologies.“


The first step towards climate friendly long-range air travel

Converting a B777, B787, A330 or A350 test aircraft to operate on liquid methane fuel (with kerosene backup).

Who is ready to pioneer with us in that field?


Felix Brenner M.Sc.

The engineering and design office was established in 2020.
Aerospace engineer Felix Brenner (University of Stuttgart/Germany) offers design service for selected industry applications, including aircraft concept design and CAD constructions for 3D-printed elements.

Feel free to contact us via email:

2019 Printed Electrics for aircraft seats. Factory Intern at AIRBUS Industries / Hamburg and in cooperation with the Institute for Aircraft Systems / University of Stuttgart. Awarded with the Hamburg Aviation Nachwuchspreis.

2019 Factory Intern, cockpit design, at PORSCHE cars.

2020 Project H-Craft. A hydrogen powered  short-haul aircraft.

2020 Patent “Electrical Connection System For A Seat” 

2021 Green Aircraft concept for a long-haul aircraft, based on Green Methane  fuel. (Master Thesis at the University of Stuttgart)


Dr. Frank Brenner

Flight Captain, Aviation Advisor for the Green Aircraft Concept and supporter. He held management positions and logged more than 10,000 flight hours on commercial  passenger aircraft B737, B747, B777, A319/320/321 and A380. 

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Contact Us

If you have any questions, please contact us. We are happy to talk with you about our Green Aircraft Concept and discuss further details.