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Flying the friendly skies with hydrogen

hydrogen plane

A pilot with a passion for aviation, Josef Kallo is determined to apply his expertise as an electrical engineer to the challenge of developing hydrogen-powered aircraft. After cutting his teeth by working on fuel cell electric vehicles with General Motors, Josef Kallo returned to his native Germany to join the German Aerospace Center in 2006, where he currently oversees Electrochemical Systems Integration, including fuel cells, batteries and propulsion for aircraft. In 2014, he was also appointed Institute Director for Energy Conversion and Storage at the University of Ulm. By tackling hydrogen fuel cell propulsion in these two roles, Josef Kallo is eager to kickstart the energy transition by ushering in the era of zero-emission air transportation for goods and passengers.

 

Air transportation is a passion for you. Can you talk about why it’s important to work on clean air transportation?

Dr. Josef Kallo, Copyright H2FLY, Jean Marie Urlacher

It’s clear that we will always have a need for the kind of rapid transportation provided by airplanes. However, the only form of aircraft propulsion involves burning fossil fuels, and there is no real alternative at the moment. That’s why it’s important to find a new solution to ensure passenger transportation without emissions. I’m also a pilot, and I fly to be free and enjoy the feeling of moving so fast through the skies. It’s something that’s very gratifying for me, so working to eliminate emissions in this area provides a chance for me to change the world for the better.

You work both on battery systems and fuel cell system applications. How do you see the two technologies evolving in the future?

As an electrical engineer, you always need to take a systems point of view. At the moment, neither battery nor fuel cells are enough on their own to power an aircraft, but the combination of the two does work. With battery alone, an aircraft may have a range of 80–100 km. On the other hand, with only a fuel cell, you can fly up to 1,200 km, but you have barely enough force for the takeoff. Each technology has its advantage: fuel cells for long range, and batteries for short bursts of high power. When it comes to aircraft propulsion, a hybrid solution combining fuel cells and battery is the best option.

Is it true that you built the first hydrogen fuel cell airplane to ever fly?

There are a lot of stories about this! For us, it was the first actual aircraft powered by a hydrogen fuel cell. But someone in France showed up after we announced and said he was first, so it’s a contested fact.

You leave no trace, and hopefully this will become the norm for the transportation system.

Boeing also took a plane into the air with batteries and flew for about 30 minutes with fuel cells. However, ours was the first to take off, fly and land completely on fuel cells. We had a small team of about 5 people working on the project, with a time frame of 13 months to plan, build and debug the fuel cell in the plane. It was challenging but also exciting.

How does it feel to fly a hydrogen plane?

We’ve had about 50 flights so far. Unfortunately, I haven’t had the opportunity to fly one myself, since all our planes are flown by test pilots. They’re the only ones who can go up in the air right now for investment and insurance reasons. They tell me that you have excellent flight performance once you are up in the air, with none of the annoyances of an internal combustion engine, such as noise. From Berlin to Stuttgart, over a distance of 500–600 km, they say it’s incredible to notice how silent the engine is and realize you are flying with zero emissions. You leave no trace, and hopefully this will become the norm for the transportation system.

Did you face any challenges in designing the hydrogen plane?

Our first challenge was to convince management that the plane would actually fly, so I’m glad that my manager is open to new ideas. When we first started in 2008, we had to take fuel cells designed for a power plant and adapt them for use on an airplane.

It was exciting to feel like we could really make a difference and change things. It was like a brand-new adventure.

As you can imagine, it was a bit awkward to go to management with a plane equipped with fuel cells from a power plant and try to convince them it could fly. It was like telling them we wanted to put a combined-cycle plant in the air, but fortunately they saw the potential.

Copyright H2FLY, Jean Marie Urlacher

It is also challenging to put completely new technology in the sky, especially since there are still no regulations governing hydrogen fuel cells for aircraft. As a result, we had to develop our own rules, certifications and methods in order to get our project off the ground.

The final challenge was finding an aircraft specialist who was bold enough to implement a fuel cell system into a plane. With our team of 4 or 5 people, we worked day and night with intense pressure and a low budget. But it was exciting to feel like we could really make a difference and change things. It was like a brand-new adventure.

Can you share some of the technical details of your hydrogen fuel-cell planes?

Our first plane was built essentially by two people, and it has a flying range of about 700 km at a maximum altitude of 2,558 meters. For our second plane, which we are using now, we expanded the team to about 15 people. It can carry 4 people in total and has a payload of 450 kg.

Up to 40% of Frankfurt airport’s 50 million annual passengers fly in from distances under 1,500 km to connect to a longer flight. We could transport all these passengers with a 70-seat hydrogen-powered aircraft for intraregional air transportation.

For the moment, it has a range of about 800 km, but we will continue to develop it this year to achieve a range of 1,300 km. We’ve taken 32 flights with the new plane, with the highest altitude of 1,700 meters. Our goal with these first tests was not to set any world records, but instead to gain experience with these systems. We’ll continue using this plane through 2021, then we will start a new project in 2022.

How do you plan to develop hydrogen fuel cell planes in the future?

Copyright H2FLY, Jean Marie Urlacher

With the technology we already have, we can carry up to 40–60 passengers. With the technology improvements we expect to make in the next couple of years, I think we can develop a 70-meter aircraft with a 2,000 km range that can travel at 600 km an hour. This is definitely in our development roadmap, but to achieve this goal, we will need to make advances in terms of increasing hydrogen storage capacity, integrating high-power fuel cell stacks and improving aircraft integration through high-quality modeling and development.

There have been a number of times when innovation has thrived in aviation. Do you feel like hydrogen could be the next big thing in regards to emissions management?

There was definitely a boom in aircraft development in the 1960s, and then there was an advance in materials used to make airplanes lighter and quieter in the late 1990s into the 2000s. But even with this new technology, we still have a huge need for new technologies to reduce emissions, since our needs are only growing in this area. That’s why we need to take the next step with hydrogen.

What role will hydrogen technology play in existing air traffic?

With the technology we have today, it is possible to carry 10–20 passengers with an air taxi. You can also power other airborne devices for about 120 minutes, flying emissions free in the city and between cities. Finally, you can build planes with a range of up to 2,000 km to carry up to 70 passengers.

Germany had the opportunity to move forward quickly with solar power, based on the rules and regulations implemented in 2002 and 2006. That led to a tremendous amount of installed renewable power in Germany.

Up to 40% of Frankfurt airport’s 50 million annual passengers fly in from distances under 1,500 km to connect to a longer flight. We could transport all these passengers with a 70-seat hydrogen-powered aircraft for intraregional air transportation. At the moment there are no regulations in this area, but in the future we could envision a regulation mandating that if we have the technology to fly emissions-free, then we must use it. From that perspective, I think there is a bright future for hydrogen systems.

Would you say that Germany is particularly interested in hydrogen as a systemic solution?

Germany had the opportunity to move forward quickly with solar power, based on the rules and regulations implemented in 2002 and 2006. That led to a tremendous amount of installed renewable power in Germany.

There is a realistic chance worldwide to build a hydrogen energy system based on renewables, because we have very cheap electric energy at the moment.

So logic says that if we have a lot of renewable power, we should develop zero-emissions hydrogen infrastructure to store renewable energy and also use hydrogen for transportation and other energy applications. We definitely have the chance to do that in Germany.

Copyright H2FLY, Jean Marie Urlacher

But worldwide, there are many strong business cases for emission-free hydrogen infrastructure and energy system integration. For example, in large swathes of the southwest USA, you can access massive volumes of cheap renewable energy. There is a realistic chance worldwide to build a hydrogen energy system based on renewables, because we have very cheap electric energy at the moment. Europe has a huge chance to implement the fuel cell and hydrogen technology developed in many countries throughout the Union. Asia and the United States have already started to implement these technologies, even though their efficiency does not meet the high standards we have in Europe. In those regions, they may not have the most efficient technology, but they will have usable technology. I think we need to adapt our regulations in Europe to implement emission-free technology.

How do you see the public perception of hydrogen in Germany?

At the moment, I would say the perception is generally positive in Germany. We need to get more information to the public, because people are interested in using the technology. But we have to take the responsibility to approach the public and implement these technologies. We are seeing more engagement from communities that want fueling stations and a connection to hydrogen infrastructure. We are also seeing a lot of activities, such as ride-hailing, expressing interest in moving people with hydrogen. We’ve also seen interest in hydrogen buses, so we definitely have an opportunity to move forward with this technology.

In addition, German politicians are pursuing CO2-free and CO2-minimized technology, so now we have a lot of new institutes to research and develop new industrialization processes to bring emissions-free energy systems into the industrialization phase and into industrial processes.