Leveraging the digital thread and additive manufacturing to develop a completely green hydrogen gas turbine

Decarbonization imperative

Siemens Energy set an ambitious goal of transitioning its entire gas turbine fleet to operate 100 percent on hydrogen by 2030 while maintaining performance, reliability and cost-effectiveness. This challenge required overcoming significant technical and operational hurdles because hydrogen presents fundamentally different combustion characteristics compared to natural gas, including higher reactivity, elevated thermal loads and design complexity.

“Hydrogen is a fundamental part of the Siemens Energy strategy for decarbonization,” said Quan Lac, vice president of additive manufacturing (AM) at Siemens Energy. “In our gas services business, we’re looking at a fuel flexibility strategy where we’re transitioning to an all-gas turbine fleet burning 100 percent hydrogen by 2030.

“There are many challenges with burning hydrogen. It has different burning characteristics than natural gas and is more reactive. It has a faster flame speed and burns 200 kelvins (K) hotter because of the burning characteristics. We really needed a new design architecture.”

The HYFLEXPOWER Project

To meet their aggressive goal, Siemens Energy partnered with European stakeholders to develop the world’s first complete ecosystem for green hydrogen power generation, the HYFLEXPOWER Project. The project demonstrated a power-to-hydrogen-to-power cycle at the Smurfit Kappa paper mill in Saillat-sur-Vienn, France using a modified SGT-400 gas turbine manufactured in Lincoln, England.

During this work, AM emerged as the critical enabling technology for solving hydrogen combustion challenges. Rather than conventional casting or machining, using AM allowed Siemens Energy to design and manufacture components with unprecedented complexity.

Integrating cooling channels with additive manufacturing

The breakthrough solution for the HYFLEXPOWER Project involved embedding microscopic cooling channels in the burner geometry. By circulating cooling media through these passages prior to combustion, engineers were able to maintain material integrity despite extreme thermal loads. This solution leveraged the flexibility of additive manufacturing, something not typically available in traditional manufacturing methods.

Siemens Energy operates more than 50 metal printers across facilities in Sweden, Germany, the United Kingdom and the United States, with components accumulating several million operational hours.

“Additive manufacturing of the burner design enables us to create geometries we couldn‘t produce conventionally,” says Sebastian Piegert, head of technology for additive manufacturing at Siemens Energy. “As a digital manufacturing technology, additive manufacturing has its advantages in design flexibility and freedom.“

However, it is key that Siemens Energy integrated AM into its product road maps as a functional enabler rather than a showcase technology.

“The only reason we do additive manufacturing is to enable functional applications across our product lines,” says Lac.

Tying it all together

Recognizing that AM alone was insufficient, Siemens Energy also implemented the Siemens Xcelerator business platform of software, hardware and services, including NX™ CAD software, Simcenter™ STARCCM+ ™ software and the Designcenter software suite for design and simulation, along with NX Manufacturing and Teamcenter® software for manufacturing and collaboration.

“The Siemens Xcelerator integrated digital thread enables us to seamlessly connect design, optimization and manufacturing, thereby reducing all software interfaces to just a single one,” says Piegert. “We must develop increasingly more complex products in ever shorter periods of time. We can only achieve this with the help of digital threads. These digital threads also bring global teams together.“

With previous projects, Siemens Energy‘s engineering teams relied on disconnected software tools that did not integrate well. This fragmented approach created bottlenecks in design-to-manufacturing workflows requiring multiple software conversions. There were also collaboration challenges among global teams working on complex iterations, version control and data consistency across distributed engineering centers. These issues were magnified by the rapid iteration cycles necessary for hydrogen burner optimization. To address this issue, Siemens Energy deployed the Siemens Xcelerator.

The success of the HYFLEXPOWER project depended on Siemens Energy recognizing that additive manufacturing and digital software are complementary, not standalone solutions.

Accelerating innovation with Siemens Xcelerator

By using Siemens Xcelerator, Siemens Energy connected its design-to-manufacturing workflow, reducing software handovers from three separate interfaces to a single, unified environment. This simplification eliminated file format conversions, reducing errors and accelerating design changes.

“Integrating the engineering of the product and the manufacturing process within a single toolchain was key,” says Piegert. “By using the NX based software chain, we reduced the number of software handovers from three to one.“

Rather than separating design and manufacturing concerns, Siemens Energy adopted an integral approach for the HYFLEXPOWER project, addressing both design and manufacturing needs simultaneously. This clean-sheet methodology allowed them to optimize components for both functional performance and production efficiency. For example, when last-minute modifications were required, such as altering hole diameters or angles, engineers could implement changes directly within NX and immediately generate updated AM machine files.

“Connecting the entire digital thread is significantly more efficient, enabling faster operations, reducing storage needs and providing all necessary tools within a single, integrated environment,” says Lac. “This allows for seamless global collaboration across all facilities. “

This integrated digital environment enabled unprecedented design velocity and accelerated productivity. Before manufacturing any hardware, the team completed about 1,000 design iterations using simulation and digital optimization, achieving 26 iterations of distinct burner design variations within the project timeline. That feat that would have been impossible without digital tools and AM. Without Siemens Xcelerator and AM, the team estimates it could have achieved only 25 percent of the 26 design iterations that were created.

“We optimize the fluid dynamics using Simcenter Star-CCM+ and then finalize the design model in Designcenter and NX CAD,” says Piegert. “The additive build job and final machining operations are programmed in NX Manufacturing. All of our data and processes are managed centrally in Teamcenter.“

Siemens Xcelerator made the digital thread accessible to distributed Siemens Energy teams across multiple continents. Engineers could access and update model status and machining files in real time, making sure everyone worked from the latest version. This global connectivity proved essential for a project of this complexity and scale.

Quality and collaboration metrics

By reducing the number of software interfaces from three to one, the HYFLEXPOWER project eliminated handovers and associated errors. This was done using Teamcenter product lifecycle management (PLM) software, enabling all global teams to access the latest model versions, enhancing efficiency and reducing rework. Furthermore, testing iterations in controlled combustion rigs under high-pressure conditions enabled rapid feedback cycles without full-scale engine testing costs.

“We focus on how to control the production value chain from design to delivery,” says Lac. “Our collaboration with Siemens is critical in that regard, helping us make sure that we control part costs, quality and get the project done on time.”

End-to-end digital thread

The Siemens Xcelerator ecosystem provided a seamless digital thread from concept through production: Engineers transformed ideas into digital models and conducted high-fidelity combustion simulations.

Computational fluid dynamics (CFD) analysis was used to refine designs based on fluid dynamics and thermal performance. There were direct translations from design to AM machine files without intermediate conversions, and test results from combustion rigs, which were fed back into simulation models, enabling continuous refinement.

This closed-loop approach accelerated innovation cycles while maintaining rigorous quality control.

An impactful project

The result of this holistic process, including powerful software and cutting-edge manufacturing, is the new HYFLEXPOWER hydrogen burner design, which substantially reduces carbon. This was proven by using a modified SGT-400 gas turbine operating on 100 percent green hydrogen, saving about 65,000 tons of carbon dioxide (CO₂) per year compared to natural gas operation. That’s equivalent to removing about 14,000 vehicles from roads annually and equals annual emissions from about 7,000 homes.

Furthermore, the burner was designed and manufactured without temporary support structures, eliminating manufacturing waste and demonstrating exceptional design optimization and manufacturing capability. By addressing functional and manufacturing aspects simultaneously from design inception, the team optimized both environmental performance and production efficiency.

Siemens Energy’s success with the HYFLEXPOWER project establishes a foundation for scaling hydrogen technology across its global turbine portfolio. The company plans to expand hydrogen capabilities, scale AM, enhance digital integration and support the energy transition. The success of this project demonstrates that with the right combination of advanced manufacturing technology, integrated digital tools and collaborative engineering practices, organizations can solve previously intractable challenges while advancing sustainability goals.

Siemens Energy‘s HYFLEXPOWER project exemplifies how Digital Transformation and advanced manufacturing converge to drive innovation in critical global challenges. By integrating additive manufacturing with Siemens Xcelerator, the company achieved unprecedented design speed, environmental impact and manufacturing excellence.

The HYFLEXPOWER project demonstrates that AM is not merely a prototyping technology but can be a strategic manufacturing approach for solving complex engineering problems and enabling commercial product development. Combined with an integrated digital thread, AM becomes a powerful catalyst for innovation, enabling organizations to accelerate time-to-market, reduce errors and deliver solutions that address humanity’s most pressing challenges.