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Hydrogen Technology Centre

Institute of Materials Research

Partial Institute Materials Technology


Thomas Klassen: One Goal in Mind

What drives materials researcher Prof Thomas Klassen?


Photo: HZG/Christian Schmid

Prof. Thomas Klassen heads the Materials Technology Institute at the HZG.

A strange vehicle is parked in his garage: The two rear wheels are positioned very close together and the only door is located toward the front. You open the car as if it were a refrigerator. You can guess how Thomas Klassen (50) approaches science from this green Isetta (manufactured in 1957). It’s a symbol of his academic career: a career between vision and necessity, a preference for practical application, which feeds off of theory and good networking.

“I always wanted to create something tangible that advances society,"

says Thomas Klassen, referring to his beginnings. After he graduated high school, he studied physics in Dortmund, where everything was theory. It was a “shock,” he says today. After only seven semesters, he began his master's degree work as one of the first in his class. “I wanted to get the theoretical stuff over with as quickly as possible so that I had more time for the practical side," he says. He refers to the months in the laboratory as "the best of his university studies.”

He was then offered a job in the commercial sector. But Thomas Klassen had other plans: “I wanted to be financially independent, but hadn’t decided on my focus of content.” He went to Geesthacht, to what was known as the GKSS at the time, to work on his doctorate. Three years later and a PhD to his name, he moved to the United States where he created a laboratory for high energy mills and nanocrystalline materials. He later returned to Geesthacht to lead his own department while also working toward a professorship (Habilitation) at TU Harburg. He was subsequently appointed professor at Hamburg's Helmut Schmidt University and soon thereafter became institute director in Geesthacht.

"I thought it was very important from the very beginning to find as many people as possible who were working on the same thing,"

says Thomas Klassen. Networking as a principle: his doctoral students speak of the enormous freedom that also “accompanies great responsibility” for each person working for him. What is remarkable is how many projects in Klassen’s institute are financed through EU cooperations. One would say about fundamental researchers that curiosity is what fuels them. For Thomas Klassen, it's the other way around: fuels are the subject of his curiosity. He dreams of a car that can drive from Geesthacht to Sicily without filling the tank once. The energy would come from the chemical element in the periodical table designated with the letter H: hydrogen.

Mobile hydrogen tanks were considered an insurmountable obstacle even in the 90s. They were either too large or too heavy or too inefficient at the time. Could the problems be resolved by binding hydrogen to a light metal hydride and releasing it as needed? First attempts at using this variant were, however, too slow: it takes several days to load such a tank. But in the early 2000s, Thomas Klassen's team made a breakthrough: loading their finely milled hydride could be done in one minute. In cooperation with European partners, they are building a light and compact hydrogen tank that can be filled in under ten minutes. Concrete application for a car would work as follows: Klassen’s hydrogen tank would feed a fuel cell, which would in turn feed the battery of an electric car, thus increasing its range enormously. Refuelling would not require a power cord as it does today, but only hydrogen. Instead of sitting for eight hours connected to a socket, the car would be back on the road in a few minutes. The only emission while driving would be pure water vapour.

The Geesthacht researcher’s work is also relevant in the context of energy transition. We’re faced with the problem of saving electrical energy, both economically and efficiently.

“Because the sun isn’t always out and the wind isn’t always blowing either - sometimes we need energy when none is produced. And vice versa: sometimes the sun and wind produce much more energy than we need at the time. Today hydrogen can already provide a good form of storage for energy that has been produced from regenerative sources.”

But how good is the mobile application? There is a problem in making HZG’s hydrogen tank function in electric cars: the temperature. The first studies required a temperature of three hundred degrees Celsius to release the stored hydrogen. “We’ve managed it at 240 degrees since then,” says Klassen. But it’s still too much: modern fuel cells work at temperatures of 120 to 180 degrees. This means there's a gap of sixty degrees remaining. “That’s exactly what we’re working on at the moment,” he adds.

The vision remains: perhaps our cars will actually run on hydrogen in a few years. There are a lot of political decisions, however, that also play a role according to Klassen. Getting his work to at least function technically is something he wants to demonstrate. That’s precisely the reason he bought his green Isetta.

“One day I’m going to convert this car to hydrogen. It’s light and therefore needs little energy. And it has sufficient space for a tank and a fuel cell.”

When Thomas Klassen comes home from work, at first glance you'd simply see a father who is excited by technology and who loves old cars. But what really stands in his garage is the motivation and goal for a complete, fulfilled professional life.

Author: Jochen Metzger
Portrait from in2science #2 (July 2015)