Retrofit project makes micro gas turbines hydrogen-compatible

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Retrofit project makes micro gas turbines hydrogen-compatible
by Robert Schreiber
Berlin, Germany (SPX) Dec 08, 2024

The German Aerospace Center (DLR) and Power Service Consulting (PSC) have successfully retrofitted a commercial micro gas turbine to operate on pure hydrogen. This conversion aims to enable climate-compatible power generation with significantly reduced nitrogen oxide emissions.

Optimizing existing infrastructure for hydrogen

Given the cost and time associated with building new power plants, retrofitting existing natural gas-fueled turbines offers a cost-effective pathway toward hydrogen compatibility. Hydrogen retrofits provide a practical solution for adapting to renewable energy requirements without constructing new facilities.

Supporting grid stability

Gas turbines currently play a vital role in stabilizing energy grids, particularly during peak loads or "dark doldrums," when wind and solar power output drops. While conventional turbines rely on natural gas, emitting carbon dioxide, retrofitting them for hydrogen offers a cleaner alternative. Hydrogen, produced using renewable energy, can fuel these plants without carbon emissions.

Innovative retrofit process

In the Retrofit H2 project, DLR and PSC demonstrated a pilot conversion of a micro gas turbine from Ansaldo Green Tech. The turbine, capable of running on pure hydrogen or hydrogen-natural gas mixtures, represents the first marketable retrofit for micro gas turbines.

DLR researchers replaced the turbine's combustion chamber with a hydrogen-compatible design, overcoming challenges such as hydrogen's high reactivity and flame speed. Martina Hohloch, leading the project, explained, "The high chemical reactivity of hydrogen is particularly challenging. It has a flame speed around ten times greater than natural gas and the ignition energy is lower by the same factor. This makes safe combustion difficult."

Successful testing on pure hydrogen

The pilot plant underwent testing at the H2-Container Technical Center at DLR Lampoldshausen. It operated successfully with pure hydrogen, delivering full 100-kilowatt electrical output for extended periods. The plant has since clocked nearly 100 operational hours on hydrogen.

Fuel flexibility ensures adaptability

The retrofit also includes a system to handle a range of fuel mixtures. Until green hydrogen becomes widely available, plants can use varying ratios of hydrogen and natural gas. Adjustments to the turbine's control and safety systems ensure optimal performance across all fuel types. Testing confirmed that emissions remained under 15 parts per million (ppm) nitrogen oxides, well below natural gas limits.

Decentralized energy solutions

Micro gas turbines are already used in facilities with combined heat and power needs, such as hospitals and hotels. Their adaptability to various fuels, including industrial waste gases, adds to their appeal for decentralized energy systems. When paired with storage systems, these turbines can enhance energy resilience for urban neighborhoods or small communities.