Jenny Larfeldt: ‘You could build everything on hydrogen’

Professor Jenny Larfeldt is Principal Key Expert at Siemens, working on industrial gas turbines. She joined Siemens in 2004 as a Combustion Team Manager. In 2014, she was appointed as the Senior Combustor Expert with over ten years’ experience in this field. Between 2016-2019 she was also adjunct professor at the department of combustion physics at Sweden’s prestigious Lund University.

What's involved in adapting gas turbines to hydrogen?

There are a lot of things to consider. First you have the core, which is made up of the most complicated parts: the compressor, the combustor, and the turbine. Together we call them the "core components". The combustion chamber has to be able to cope with high hydrogen content. So that's what we have been doing in our R&D: developing the burner design, making it more resistant to flashback behaviour, and adapting it for the specific issues that accompany hydrogen.

When testing our burners, we always start out burning with natural gas, and then gradually increase the hydrogen content. Here you also have to think about the auxiliary system: the fuel-feeding pipes, the valves, and the flow controllers. Really just everything – all the equipment needs to be hydrogen-tight. 

Jenny Larfeldt, Siemens

Do you have to take extra safety measures with hydrogen?

Hydrogen does need special safety precautions. Everything has to be adapted for hydrogen’s tiny size. It’s such a small molecule, so you need to be especially careful. It’s not just the turbine that needs to be adjusted – it's also the enclosure, the ventilation system, the gas detectors.

And you need a fire extinguishing system, which has to be adapted to extinguish a hydrogen fire. We’ve learnt all this as we go - it’s part of the process.

Describe your most recent hydrogen research project. What did you learn?

We always have an incremental approach to introducing hydrogen into the fuel mix for our burners. We start out with natural gas mixed with hydrogen. Previously we’d achieved 15 percent, and then 30 percent, and then 60 percent. And recently we conducted a new test, which was actually very scary because we weren’t sure it would work.

But it did and reached an important milestone in the process. We achieved 75 percent hydrogen by volume in a mixture with natural gas in the burners. And 75 precent actually accounts for half of the energy content of the fuel, which translates into a reduction of the carbon footprint by 50 percent. It was a pretty big step.

Will we see that come to market soon?

We hope so. But right now, we are in the process of checking all the details, producing material for the sales team describing what guarantees we can provide, and how it works. So, we are dealing with a lot of demands. It keeps us busy, but it’s nice.


How does it feel to get to that stage after all that hard work?

It feels good because it confirms that we’ve been doing the right thing for many years. We’ve spent more than 10 years looking into hydrogen, understanding more and more with each experiment.

Another thing I like to point out is that we also 3D print our burners. Additive manufacturing has really helped us in iterating the burner design and allowed us to arrive at this flashback-resistant design that we have confidence in. That and the help of academia.

How has academia helped you and your work with hydrogen at Siemens?

In our recent project we saw the tendency of the burner flame to change its turbulent behaviour, the shape of the flame, and the position of the flame. But then, together with Lund University, we undertook incredibly advanced diagnostics.

The university shot laser beams into the flame and they really captured, at a much higher resolution, the flame surface and all the combustion radicals. It’s really pretty amazing and inspiring. But it's very hard to say, "Yeah, working with academia helped us increase our sales from 30 percent to 50 percent." It's not like that, but it keeps us confident and on target, and then they also offer us guidance in our design work.

How does Siemens view the potential for hydrogen as a clean fuel source?

From my perspective of industrial gas turbines, I think it's very important to listen to our customers. It’s also very positive that we have partnered with Linde Engineering to explore the use of renewable energy and energy storage to help clients in the petrochemical industry meet carbon emissions and environmental sustainability goals.

Of course, I would like to have reached 100 percent green hydrogen right now. But we also need to understand what's the best use of our gas turbines. My feeling is, why should our customers only use this really nice green hydrogen for power and heat? Shouldn't they use it to produce biodiesel or some of their products? And then maybe we can run our turbines on some waste gas. That's more how things look from our perspective. But no one knows, so I think we have to be flexible and maybe run on different mixtures of fuel. I mean, of course we should be able to run on green fuels, but who knows what customers can afford to fuel our turbines with?

What does the future of hydrogen hold?

This little molecule is important in so many aspects. We can use it for energy but it's just as important for the chemical industry. You could build everything on hydrogen, and I guess that's a very beautiful, appealing idea - the hydrogen society.

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