Turbo Expo 2023: Gas Turbines’ Role in a Sustainable Future

The American Society of Mechanical Engineers (ASME) Turbomachinery Technical Conference & Exposition celebrated its 67th confluence in Boston’s Victorian-era Back Bay, June 26-30, 2023. A host of turbomachinery experts, academia, and government converged at the Hynes Convention Center to present technical findings and tutorials and participate in panel discussions on the most pressing matters in the industry, all to the tune of sustainability. Conversations at this year’s show shifted away from the traditional oil and gas sectors toward alternative fuels and decarbonization.

“The theme of this conference is to showcase the sheer continuous collaboration and innovation taking place in the industry to innovate, empower, and propel energy toward a more sustainable future,” said Tom Costabile, ASME Executive Director and CEO.

Nearly 2,600 experts, 119 exhibitors, and 26 countries were represented in over 1,000 technical sessions, making it one of the most densely packed and informative ASME Turbo Expos to date. New at this year’s Expo was a student mixer, and, on a trial basis, ASME brought in 40 high school students from two different areas to give them exposure to turbomachinery sciences.

And besides being a hub of all things technical, another important theme of the show was its diversity and inclusion efforts. “Turbo Expo is striving for diversity and gender balance, with more women participating than ever before,” Costabile said. “This conference has set the groundwork for rich discussion and idea sharing.”

For example, GE and Cadence Design Systems hosted a “Celebrating Women in Turbomachinery” dinner during the Expo, which was vibrantly attended. Here, conference registrants were able to share their stories, network, and empower each other in a casual atmosphere, while promoting women working in the turbomachinery industry.

Gas Turbines’ Role in Decentralized Energy Systems

Day one featured a five-person expert panel on The Role of Gas Turbines as Part of Decentralized Energy Systems to Address the Energy Trilemma. Panelists opened with a discussion on why decentralized energy systems have yet to be broadly adopted.

Alberto Traverso, Chair of Energy Systems at the University of Genoa, spoke about the World Energy Council's sustainable energy promotion and the Energy Trilemma Index, which includes 90 countries, each at different points on the path toward 2050 climate mitigation goals. He said ammonia may play a role in ship propulsion and power generation, although its ultimate use remains largely uncertain. Traverso stressed the importance of adaptation strategies for the gas turbine industry and emphasized the need for technologies, such as grid flexibility, distributed combined heat and power (CHP) energy storage, and gaseous clean fluids.

Rainer Kurz, Manager of Gas Compressor Engineering at Solar Turbines, highlighted the importance of balancing supply and demand, especially given the increasing fluctuation in renewable energy supplies. He said that energy sources like natural gas are effective at supplying stable, reliable power. However, he underscored the challenges posed by geographical locations—the areas abundant in solar and wind resources are often not located where energy is most needed, which introduces transportation challenges for gases like natural gas, CO₂, or hydrogen.

Peter Kutne, Head of the Gas Turbine Department at the German Aero Center (DLR), argued for the role of gas turbines in supporting decentralization, emphasizing their fuel flexibility and load flexibility, especially with hydrogen and other renewable gases. He elaborated on the potential benefits of decentralized systems, including reduced infrastructure requirements and the possibility to retrofit existing power plants for decentralized use as a hydrogen entry point.

Jim Kesseli, Principal Mechanical Engineer and Founder of Brayton Energy, emphasized the economic aspect of decentralization, which interestingly touched on how cogeneration will play a role. He acknowledged the challenges of introducing new products into the decentralized power generation sector, stressing that these installations must compete with utilities in terms of capital costs to be viable. He touched on gas turbine co-production with hydrogen and ammonia, the importance of peak-load power plants in connection with renewables, and the opportunities presented by small nuclear reactors in the energy mix. Most importantly, so-called “dirty” power—power generation with high emissions—will likely remain the best choice for emergency power. This is in contrast with renewable sources, which are more intermittent in nature.

And finally, Justin Rathke, President and Founder of Vergent Power Solutions, expressed concern about market conditions. He emphasized the role policymakers play in shifting the market and pointed out that geographical location is critical in this discussion. In essence, certain regions have policies that either deter or support certain strategies, such as more renewables, initial capital costs, and others. He also added that combustion technology remains necessary for base-load power. In certain applications, microturbines could be more economical than renewables.

Technologies for a Sustainable Future

On day two, another panel of experts, featuring executives from Pratt & Whitney, GE Aerospace, Siemens Energy, and Rolls-Royce, discussed the challenges and opportunities of sustainable aviation. Dr. Kathleen O'Brien, Vice President, Technology & Innovation at Siemens Energy, addressed the power-generation sector and how Siemens Energy is addressing net-zero goals and some of the challenges and technologies available.

“As an electrical engineer, I can relate to the fact that demand growth and decarbonization can seem to contradict,” she said. “Through both electrification and starting to use hydrogen in some of our gas turbines, we can power clean loads with clean energy.”

Siemens Energy views a clean-energy future through the lens of four different focus areas (decarbonization, demand growth, decentralization, and digitalization), and using what the company calls “the five fields of action,” it develops technology to address these focus areas.

• Power-to-X (e.g., hydrogen-powered gas turbines)
• Energy storage
• Decarbonized heat and industrial processes (e.g., electrical heat pumps and heat waste recovery)
• Condition-based service interventions
• Resilient grids and reliability

In relation to net-zero goals, Siemens Energy has “technology that allows more renewables to get on the power grid, which allows us to integrate more renewables quicker and to then take advantage of regional ecosystems with hydrogen and other technologies to do things at a much faster pace,” O'Brien said.

Other technologies being developed include electrolyzers and fuel cells that can help the industry more efficiently and more cleanly run heavy-duty vehicles or trucks as well as technologies that address hydrogen from a cost perspective.

O’Brien said that it is a lot easier to do a hydrogen-based gas turbine on land, relative to challenges faced by aircraft applications. Currently, the company’s gas turbines co-fire between 15% and 75% hydrogen by volume, depending on the turbine frame. There is a lot of interest in hydrogen co-firing on gas turbines even though the infrastructure and the business case are not there today. The company also has a technology path to operate its gas turbines at 100% hydrogen by 2030.

She highlighted a recent collaboration between Siemens Energy and Constellation that offered real-world insights into hydrogen blending with natural gas. In the demonstration, they reached 38% by volume hydrogen blend in Siemens’ SGT6-6000G turbine, allowing them to produce over 36 MW on the gas turbine and 54 MW on combined cycle from the energy content of the hydrogen. It stayed within the required NO_x emissions levels without steam or water injection.

“What this means is 16% of the total MW generated were generated by hydrogen,” O’Brien said. “This reduced the carbon emissions by 16%, but without any increases in NO_x.”

The Potential of Hydrogen

Day two ended with a discussion on Gas Turbines’ Role in the Decarbonized Power Generation Portfolio, in which energy companies revealed their strategic shift toward integrating hydrogen into gas turbines. This session was part of the broader conversation on navigating the energy transition.

In the scope of the growing recognition of hydrogen's potential as a synthetic fuel, Peter Stuttaford, CEO of Thomassen Energy B.V., revealed his company’s intent to retrofit natural gas systems with hydrogen. Europe's decision to adopt its pipeline systems to facilitate hydrogen and potentially ammonia transport underpinned these discussions. This transformation, part of the “Backbone 2025” project, aims to equip power plants with easy access to hydrogen, much like natural gas.

The idea of importing and storing ammonia/hydrogen in vast salt caverns was also addressed, highlighting an approach to gigawatt-scale energy storage. Presenters emphasized the need to retrofit existing power plants with low-carbon solutions, and the possibility of achieving high-efficiency rates of up to 80-90% in CHP applications.

Ghenadie Bulat, Siemens Energy's Head of New Technologies Gas Division, argued that "the energy system of tomorrow is a mix of different energy carriers," and predicted that by 2050 electricity will account for half of energy consumption. Bulat noted that although gas will likely persist in the energy mix post-2030, regional policies will shape diverse decarbonization approaches.

Bulat emphasized the importance of managing the residual load—the gap between demand and available renewable energy. He identified gas turbines as critical in this role, maintaining energy security in times of renewable volatility and providing rapid grid balancing. He also pointed out the opportunities for carbon capture and storage (CCS) in natural gas plants, steam methane reforming, wind hydrogen, and hydrogen derivatives like ammonia, methanol, diesel, and biofuels.

Echoing Bulat's sentiments, Fabien Codron, Technical Director - Hydrogen Solutions for Decarbonization at GE Vernova, stressed that decarbonization would require bespoke solutions that consider each region's unique resources and needs. Codron also discussed the challenges of using hydrogen as a fuel, expressing optimism that technological hurdles could be overcome with research and development.

Carlos Koeneke, Chief Technology Officer of Mitsubishi Power, also presented a roadmap for decarbonization, suggesting improvements in efficiency, the integration of ammonia in boilers, the implementation of CCUS, and the use of hydrogen and ammonia in gas turbines.

The presentation concluded with discussions on the upcoming combustion tests for ammonia at a facility in Nagasaki, and the establishment of the Takasago hydrogen park, a site for hydrogen technology verification. The ongoing challenges associated with the capacity constraints of transitioning to hydrogen were also recognized, underlining the industry's urgency to find solutions.

OEMs Innovate

Day three ended with a panel discussion featuring several OEMs and a discussion about innovations and various applications of gas turbines and machinery in the future of energy systems.

Caroline Marchmont, Director, R&D Execution at Ansaldo Energia, said the next major milestone in the industry’s pathway to net zero is moving gas turbines to hydrogen, which is expected to happen sometime between 2030-2040. Further, “Once we replace the coal plants, that will reduce the CO₂ emissions for that plant by about half,” she said.

Another factor to consider is the sustainability of existing assets.

“What can we get out of what we already have?” Marchmont said. “And how can we reuse technology as well as advancing technologies to improve on the existing assets?” And this includes adapting existing technologies to support renewables.

Improving existing assets or retrofitting can be tricky, but with its MXL3, Ansaldo Energia upgraded the first two stages of the low-pressure turbine. The company already has a combustor that's capable of 45% hydrogen, and it’s updated the compressor to optimize the performance and better match the turbine. With all of this, it gets up to 35 MW and 1.6% combined-cycle efficiency improvement.

Marchmont said this, among other advancements/upgrades, is possible through collaboration and cooperation, which was stressed by many presenters throughout the conference.

Dan Reitz, Manager of Product and Technology Strategy at Solar Turbines, outlined the company’s strategic plan to reduce emissions and enhance the use of alternative fuels. Reitz mentioned how the company is prioritizing four areas: operational efficiency, methane abatement, hydrogen fuel flexibility, and CCUS.

Solar Turbines is leveraging a digital platform to optimize operational efficiency and has developed an integrated mobile solution for methane abatement. In terms of hydrogen fuel, the company is expanding its capacity in collaboration with several energy companies. The aim is to gradually mix hydrogen into their products up to 100%.

In terms of CCUS, Solar Turbines is focusing on technology to enhance CO₂ concentration in the exhaust stream, which will make the capture process more cost-effective. They're also testing a pilot project in partnership with Chevron. Despite uncertainties in the energy landscape, Solar Turbines remains optimistic about the potential of market-driven solutions and legislative incentives to advance low-carbon goals.

Michael Hughes, Hydrogen Combustion Technology Integration Leader at GE Vernova, stressed the role of gas turbines in transitioning toward renewable energy. The push for decarbonization has prompted a shift toward efficient natural gas plants, but the role of these plants is evolving. Hughes predicts they'll increasingly serve as flexible power sources—for example, starting multiple times a day or load-following as required. Pertinently, Hughes stated that gas turbine core components will not need extensive changes to accommodate these alternative fuels like hydrogen or ammonia.

According to Hughes, GE has developed combustors for hydrogen fuels, and it is confident about the potential of axial fuel staging systems in this application. He touched on how the company is collaborating with Shell to create a 100% hydrogen-capable E-class system. Further, a Department of Energy (DOE)-funded program is in place to develop a similar system for H-class turbines. Hughes acknowledged challenges such as maintaining operability across a range of hydrogen levels and ensuring flashbacks don't occur. The aim is not just to transition to renewable fuels, but to do so in a way that integrates seamlessly with existing infrastructure and operations.