Sustainability Report 2021



On the way to emissions-free flight

The future is climate-neutral

This is not wishful thinking, but a very specific vision of MTU. Not only do we want to revolutionize aviation with new propulsion concepts, but we also aim to restructure the production and maintenance operations at our sites.

Acting for tomorrow, today.

No words, no numbers—just a series of vertical colored bars are enough to visualize the progressive warming of our planet. The climate stripes from Prof. Ed Hawkins at the University of Reading illustrate what other scientists can confirm. We must take action. According to the Intergovernmental Panel on Climate Change (IPCC), global warming is already having an impact on billions of people. Although the pandemic slowed energy-related CO2 emissions in 2020, they rose again in 2021—to the highest level ever (IPCC). The good news: it is still possible to limit warming to 1.5 degrees. To do this, we need to slash emissions immediately—by more than 40% by 2030 and to zero by 2050. Even then, temperatures would temporarily exceed the 1.5 degree rise, but would subsequently fall again slightly and so meet the target.

Everything depends on concrete implementation. Therefore, climate action is an integral part of MTU’s corporate strategy. We are pursuing the long-term goal of emissions-free aviation. And we are also implementing concepts to reduce the carbon footprint of our own operations in production and maintenance at our sites, to the point of attaining carbon neutrality.


Each stripe represents the average temperature for a single year, relative to the average temperature over the entire period from 1850 to 2021. Shades of blue indicate cooler-than-average years, while red shows years that were hotter than average.

Our agenda for the future – emissions-free flight

Clean Air Engine (Claire)

With our Claire technology agenda, we are taking off into a new future of aviation. Claire is derived from global climate goals such as the Paris Agreement’s 1.5 degree target and the EU Green Deal’s target of greenhouse gas neutrality by 2050. In Claire, we formulated possible aviation solutions and identified potential at the propulsion level. Because we are certain: we can do it and make a major contribution to reaching the important global climate targets through emissions-free aviation. The first stage (Claire 1) has already been successfully implemented through the deployment of the geared turbofan—the initial version of Claire dates back to 2007. Now MTU has written a new chapter in this green success story and is playing a leading technological role in ushering in the necessary paradigm shift in aviation toward emissions-free flight.

Climate impact of aviation – the latest research findings

The UN Intergovernmental Panel on Climate Change (IPCC) reports that the climate impact of air traffic is due mainly to CO2 emissions, ozone production as a consequence of NOx (nitrogen oxide) emissions, and the formation of contrails and cirrus clouds. According to the International Energy Agency, global air traffic is responsible for some 2.7% of CO2 emissions around the world (data from 2015). Conducted in 2020, a new international study led by Manchester Metropolitan University in collaboration with the German Aerospace Center (DLR) evaluated all the emissions from aircraft engines that contribute to climate change using an advanced IPCC metric. The study included CO2, NOx, water vapor, soot, aerosol and sulfate aerosol particles, contrails and cirrus clouds in its calculations, finding that global aviation is responsible for 3.5% of human-induced climate change. It also shows that CO2 emissions are responsible for only one-third of aviation’s impact on the climate, with the other two-thirds due to non-CO2 effects. Contrails and cirrus clouds (clouds of ice crystals) also have an impact on the climate; they form in the atmosphere under certain temperature and humidity conditions, triggered by particle and water emissions.

Sustainable aviation fuels belong to the future

But what are they?

Sustainable fuels are already imperative in the short term on the way to climate-neutral aviation. Sustainable aviation fuels (SAFs) can already be used in today’s infrastructure in an admixture of up to 50%. The new fuels can be “dropped in” to existing infrastructure, which means there is no need to modify the engine or aircraft. Currently, however, SAFs are used just in minimal quantities, but the climate targets can be achieved only with an immediate and significant increase in manufacturing capacity.

Essentially, there are two different methods for producing SAFs: biomass-based and synthetic fuels. It is vital that biomass-based processes do not stand in the way of food production. One way to ensure this is by converting waste and residual materials into kerosene. Compared to the methods used today, advanced processes such as biomass-to-liquid can achieve even greater sustainability, because very little in the way of CO2 emissions is generated in the production of the fuels. In addition, a diverse range of raw materials can be used, which helps avoid changes in land use.

Unlike biomass-based SAFs, the scalability of synthetic fuels is virtually unlimited. They are produced using renewable electricity or sunlight, for which the power-to-liquid (PtL) process is particularly suitable. Although this technology is known and approved, there are still no large-scale production facilities in existence. This partly accounts for the fact that prices are still very high. A ramp-up to industrial scale, however, is expected to significantly reduce the cost. To produce this PtL fuel in large volumes, sufficient quantities of renewable energy must be available. Stepping up efforts to source even more energy from renewables is therefore also central to the use of SAF.

In addition to SAF, hydrogen can be burned directly as an alternative source of power for gas turbines. The requisite modifications would be relatively easy to make. When it comes to the aircraft and infrastructure, more extensive adjustments are likely to be required, as the entire fueling system will have to be changed or the fuel systems at airports will have to be adapted. As is the case with SAF, sufficient quantities of renewable energy are needed to provide green hydrogen.

We use SAF in our test stands

Jet Blue

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Latam Airlines

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MTU Maintenance is the world’s first maintenance outfit to use SAF for test runs. The MTU subsidiary has launched this initiative with several airlines. On the test stand at MTU Hannover, the sustainable fuel made from recycled cooking oils and waste has been used to date in an admixture of 10%. In future tests, however, it will be possible to increase this proportion to 50%. The fuel causes 80% less greenhouse gas emissions per gallon over the entire lifecycle than standard kerosene. In a test run of a V2500 engine, for example, 0.6 metric tons of CO2 can be saved.

Thorsten Kleine Sextro worked for four years on the sustainable use of alternative fuels. Now his work is bearing fruit


“Sustainable technologies are becoming increasingly important and can provide a crucial competitive edge.”

Systems engineer Thorsten Kleine Sextro had already realized how important sustainable technology developments are before he joined MTU Maintenance Hannover. “While working on projects for the automotive industry, I discovered that the introduction and implementation of sustainable technologies is becoming increasingly important and can provide a crucial competitive edge.” Kleine Sextro is now project manager at MTU's site in Hannover for the introduction of SAFs in engine tests. Four years ago, when the topic of biofuels was discussed in professional circles but had little popular traction, he submitted his idea for introducing SAFs on MTU test stands to Innobox, our innovation center at the location. “Innobox opened the door,” he recalls. Thanks to the creative space that the center allows, and with support from his team, he was able to make decisive progress with his SAF idea—with the objective of finding a suitable biofuel for the MTU test stands.

After several months of brainstorming, research and inquiries—including with customers, aircraft manufacturers and fuel manufacturers—they chose a suitable kerosene with an admixture of 10% biofuel. And now initial customers are sending their engines to MTU Maintenance for green test runs.


545,000 metric tons

This is the amount of CO2 that the Clean Air
Industrial Site program has already saved.
Now MTU is going a step further.

By 2030

60 %

is the amount that CO2 will be reduced by.

Our ecoRoadmap to a climate-neutral site

MTU Green Europe

Responsible climate action requires a holistic approach. In our production and maintenance activities, therefore, we are also pursuing specific climate goals that are designed to aid efforts toward reaching of the target set by the Paris Agreement.

In the area of operational environmental protection, we implemented a climate strategy in 2021 for Munich, our headquarters and largest production site. Our goal is to reduce CO2 emissions by 60% by 2030. This will be done in the context of an ecoRoadmap, which is founded upon several principles. The most important of these are:

Expanding use of renewable energy

Through the cogeneration plant and a photovoltaic system, among other things, we already generated 10% of our energy needs ourselves last year. MTU is investing in renewable energy to reduce emissions. In addition to the operation and expansion of facilities to produce our own electricity, we are looking into the use of geothermal energy for heating at the Munich site. We compensate for any unavoidable residual emissions that arise through operations at the site by means of high-quality offsets, such that we have been able to operate the Munich location on a climate-neutral basis since 2021.

In the long term, we want to incorporate all production and maintenance facilities into our climate strategy. On the way there, we will first be expanding the ecoRoadmap into an MTU Green Europe program. By 2030, we hope to have reduced the CO2 emissions of all facilities in Europe by 60%.


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