Hydrogen and biogas: Cranking up the engine for turbine research

Turbines are the heart of conventional power plants. But they’re taking on new functions thanks to the transition to a new energy mix. Increasingly, biogas, waste, or hydrogen are being used instead of coal. Mechanical engineer Verena Klapdor explains the challenges that this poses for turbines.

 

By Ilse Trautwein

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Ms. Klapdor, classic, steam-driven turbines for large power plants are facing competition in these times of energy transition. Environmentally friendly and yet efficient turbomachines are in demand these days. What kind of research must be done here?

It’s crucial to make our turbomachines more flexible. Steam turbines in combined-cycle operation use the residual heat of the exhaust gases from the gas turbine. They not only generate additional electricity but also supply the heat in combined heat and power plants for our district heating networks and industrial applications. In these types of CHP applications, we achieve fuel utilization rates of up to 90 percent. Since the power supplied by wind and sun fluctuates enormously over long periods of time, turbines must compensate for these differences. In specific terms, this leads to increasingly more complex load curves that challenge the materials and design.

 

What are the chances of using hydrogen-containing gases as combustion material?

I believe there is a very good chance of this. Unlike natural gas and coal, hydrogen contains no carbon, which means that it also does not produce CO2 during the combustion process. But hydrogen does impose significantly higher requirements on the combustion system and peripherals, and we need to be aware of this. For example, since a hydrogen flame has different combustion properties than a natural gas flame, the existing combustion systems need to be replaced by new ones. This means that we need to re-evaluate ignition delay times, flame stabilization, nitrogen oxide formation during combustion, as well as acoustics in the combustion chamber, and develop the right technologies for the new fuel.

These research problems won’t be solved overnight.

Certainly not. It will ultimately be a matter of time, comparable to the introduction of solar technology. Early on, solar was also too expensive compared to established technologies. This situation has changed in recent years. Under the right conditions, even hydrogen can be produced and transported economically with the right policies and research efforts in industry and the research institutes. Gas turbines will then make an important contribution. They can reconvert the hydrogen produced from excess electricity into electricity and heat. In particular, existing power plants – if suitable – can be retrofitted for hydrogen operation.

 

Is digitalization a research topic?

Absolutely. Digitalization helps us automate and optimize complex calculations needed in designing turbomachines. In addition, we can digitally simulate the complex operation of a machine, for example using a digital twin, and identify the need for servicing at an early stage.

 

What are the advantages of research collectives, and the “Flexible Energy Conversion research network” in particular?

The Flexible Energy Conversion network is where all researchers and industry representatives, as well as private individuals, can learn about the current state of research. Synergies also develop, which drive the pre-competitive research. During the last meeting of the Turbomachine working group, we had a situation, for example, where a presenter reported on his research project and mentioned that he lacked special knowledge. Another participant possessed this very knowledge. Many challenges can be resolved only by bringing together people from a wide range of different backgrounds. This is made possible by the BMWI research networks.

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Aug 12, 2020

Ilse Trautwein is a science journalist.

 

This article was first published on "Forschungsnetzwerke Energie" (German language).

 

Combined picture credits: Siemens Energy

Verena Klapdor holds a doctorate in mechanical engineering and heads the gas turbine technology unit at Siemens Energy. She is the spokesperson for the Flexible Energy Conversion research network, where she heads the Turbomachine working group together with Professor Peter Jeschke of RWTH Aachen at Germany.