‘There’s no perfect fix, there’s no silver bullet’

Working on the energy transition requires looking at things from all sides says Assistant Professor Julien van Campen.

Julien van Campen: “This panel is an example of how you can already make structures lighter at lower costs.” (Photo: Heather Montague)

“I’m an Assistant Professor in the Aerospace Structures and Computational Mechanics group. I’ve been at TU Delft since 2015 and I work on designing composite structures for the energy transition. That might sound a bit abstract, so what do I actually mean? For aircraft, we try to reduce the emissions and the impact they have on the environment. One very important factor with this is going to alternative fuels, for example, hydrogen. But people often forget that you also need to reduce the amount of energy that you consume and you can achieve that by making structures a lot lighter.

This panel (see photo) is an example of how, through smart design and existing manufacturing technologies, you can already make structures lighter at lower costs. The benefit of that is you can actually make high performance composites accessible to a large range of transport applications where they otherwise might not be applicable or might be too expensive. That is one dimension of my work.

The other dimension that I work on is developing pressure vessels for the storage of hydrogen. Now that there is a lot of talk about hydrogen in the media, one of the main things that people focus on is liquid hydrogen, but there are actually three ways to make hydrogen more compact. Hydrogen carries a lot of energy per unit weight, but per unit volume, not so much. So, you want to make the hydrogen more dense. You can cool it to cryogenic temperatures, which is 20 kelvin, or 20 degrees above absolute zero and that is quite cold. You can pressurise it to pressures up to 700 bars, or 700 times the atmospheric pressure, so that is also extremely high. Or you can combine the two and that is what I’m aiming at, cryo-compressed hydrogen storage. Then you can still get the same densities as when making it liquid but maybe at a slightly higher temperature at around 70 kelvin. Materials will probably function a bit better then. The whole reasoning behind this research is combining both the cryogenic design and the compressed design, bringing both worlds together.

‘I try to inspire people to look at things from every side’

I try to inspire people to look at things from every side, 360 degrees. That’s also something that I try to do in my teaching. I’m currently supervising a group in their design synthesis exercise, the final bachelor project here at the Faculty of Aerospace Engineering. I created an assignment for them to design an aircraft that eliminates the emission of ultrafine particles whilst taxiing at the airport and during take-off and landing. Once in the air, the aircraft may switch to conventional combustion, but still with the requirement to reduce emissions significantly. And I am proud to say that my group actually just won the TU Delft Energy Challenge award for a final bachelor project for their work.

A lot of times people think we just need to reduce CO2 emissions, but there’s a lot more than that. We also need to reduce the impact on the environment in terms of ultrafine particles, for example, and material consumption. This is where technology, like with the panel I mentioned, comes into play. If you use recycled materials, that is great, but people tend to use non-recyclable materials to get higher or better material performance. However, with technology you can take a material that has been recycled and its absolute properties might be a bit worse than the optimal material. But still, by designing it smartly I can squeeze the same performance out of the part. Then that’s recyclable and high performance at the same time.

What I see happening way too often here is that people think about one thing, like we need to reduce weight, or CO2 emissions. But no, there’s a full picture we need to look at. With hydrogen, for example, nobody mentions that it’s a greenhouse gas. Even with hydrogen tanks leaking 1% to 2%, if everything works on hydrogen people estimate that it would still contribute to global warming, but orders of magnitude less than currently is the case with fossil fuels. There’s not a perfect fix, there’s no silver bullet. The main message for me is that I think you should try to look at problems from all sides.

In addition to my research and teaching, I am also the chair of True U, the LGBT+ employee resource group at TU Delft. I also try to be an LGBT+ role model for the students. This is something very important to me.

Want to be featured in Humans of TU Delft? Or do you know someone with a good story to tell? Send us an e-mail at                

Heather Montague / Freelance writer

Editor Redactie

Do you have a question or comment about this article?

Comments are closed.