Normally, we don’t cover hydrogen stuff much here at CleanTechnica. Well, at least not seriously. Often, we’re making fun of it! Why? Because for most applications, hydrogen is a terrible way to store energy. The only really clean way to make the stuff at this point is using electricity to separate the hydrogen and oxygen in water, like a high school science teacher might do. There are some other methods that may work out, but they’re not viable just yet.
Using electricity is no big deal because electricity can come from cleaner sources over time, but we have to be careful about not using too much. We’re already going to struggle to replace fossil fuel-burning energy sources with renewables, and upping our electricity usage massively would make that task even harder. So, we need to both electrify things that burn fossil fuels and try to not use too much.
The problem with hydrogen is typically that it takes so much electricity. Not only does it take a lot to separate the hydrogen out from water, but you’ve then got to compress it, pump it, transport it, pump it again, and then run it through a fuel cell to make electricity again. At every step, there are conversion losses, and you end up using several times more electricity than you would have used to just charge a battery!
But, that doesn’t mean that you can always “just charge a battery.” The problem with today’s battery technology is that it isn’t very energy dense. It just doesn’t hold enough energy per square unit of space or per unit of weight for some applications. For stationary storage, a battery can be big and heavy, and it’s not a problem. For EVs, they introduce some compromises. But, for things like aircraft and cargo ships, the batteries would just have to be too huge to fly, at least not without leaving some room in the weight budget for passengers and cargo.
So, at least for now, we’re stuck with hydrogen being the cleanest fuel, at least for some applications.
A recent press release from Airbus, the well-known maker of airliners, cargo planes, and other aircraft, shares an interesting tale about the heart of a special new plane, but be warned, it’s a plane with a cold, cold heart.
Airbus is focused on bringing zero-emissions aircraft to market by 2035 and it is using cutting edge technologies to achieve this goal. A large part of this is figuring out how to power the aircraft, and Airbus believes that hydrogen is a very promising option. Therefore, it is putting a lot of effort into researching hydrogen fuel cells.
There are two primary ways that aircraft can fly directly with hydrogen. Gas turbine engines can be modified to run on hydrogen combustion, and fuel cells can generate electrical power from hydrogen. Or, a hybrid approach using both technologies is also possible. But there is one challenge that all these options face: hydrogen has to be kept extremely cold. It must be stored at -253°C and remain at that temperature despite changes in the level of hydrogen throughout the flight.
Therefore, storage tanks for a hydrogen-powered aircraft are an essential component, but they differ from those found on regular aircraft. A successful ZEROe aircraft largely depends on these tanks being manufactured correctly; thus, they established Zero Emission Development Centres (ZEDCs) about 15 months ago in Nantes, France, and Bremen, Germany, to work specifically on designing and constructing the hydrogen tanks.
“It’s a real testament to the teamwork across our sites to see this first tank being manufactured so quickly,” said Chris Redfern, Head of Manufacturing, ZEROe Aircraft and Head of Propulsion Industrial Architect. “We want to optimise the tank for greater efficiency and to further reduce its environmental footprint: after all, a zero-emission aircraft needs to be as close to zero emission as possible throughout its whole life cycle.”
How The Experts Achieved The Goal
Airbus went to its colleagues in Nantes and Bremen for help because they already had the skill set required to address this challenge. With its proximity to Ariane Group and Airbus Defence and Space (with their experience working with hydrogen), Bremen seemed like the logical choice for manufacturing the tank. And, due to Nantes’ considerable expertise with metallic structures, they decided that was where they would produce the coldbox — which takes care of the gasification of liquid hydrogen.
Not only is this tank innovative from a technical standpoint, but it also represents a departure from more conventional methods. By embracing a dynamic and agile working methodology, the teams adopted a co-development approach which relied on quick progress through innovation, testing, failing fast, and adaptation. In other words, rather than spending time developing theoretical plans, the teams jumped straight into manufacturing prototypes which they would then test before moving onto creating an improved prototype.
In Nantes, the team took an empty warehouse and in a little over a year they built the first cryogenic hydrogen tank that Airbus has ever produced.
“It’s a real testament to the teamwork across our sites to see this first tank being manufactured so quickly.” said Redfern. “The agile methodology has delivered a great prototype and will help drive improvements in future iterations. We want to optimise the tank for greater efficiency and to further reduce its environmental footprint: after all, a zero-emission aircraft needs to be as close to zero emission as possible throughout its whole life cycle.”
The next step is to analyze the prototype with a critical perspective and ask what can be done better. The team takes the insights and testing data, creates a design for a second prototype that will have improved performance and more space while being easier to manufacture. They are already working on the second tank, which should take around another year to build and test.
Airbus says its goal is to have a tank completed and installed in the A380 demonstrator by 2026-2028. While cleaner planes would be nice to have a lot sooner than that, the world of aviation moves very cautiously. It’s good to see that Airbus is developing a safe and reliable design.
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