“You can’t have an energy related meeting these days without talking about data centres”, remarked Bobby Noble of EPRI at ETN Global’s 12th International Gas Turbine Conference (IGTC). And of course IGTC 25, Brussels, 14-15 October, proved to be no exception, with Bobby noting a shift to smaller gas turbines for data centre projects to get round five-year delivery delays being experienced for larger machines.
That was another recurring theme of the event: the current, partly-datacentre-driven, boom being experienced by the gas turbine business, resulting in unacceptably long lead times. A nice problem to have, you might say, “positive pain” is how Christer Björkqvist, Managing Director of ETN Global, describes it, “what you feel when pushing yourself the limit, it hurts but you are making progress.”
Dealing with immediate supply chain challenges arising from burgeoning demand has to some extent replaced longer term concerns, eg reducing emissions, among the preoccupations of gas turbine market players. Nevertheless, the stated aim of the Brussels event was “advancing turbomachinery innovations and strategies for net zero pathways” and a number of the presentations addressed the topic of decarbonising gas turbines, with the idea that they can be a destination rather than a transition technology, having plenty to offer in support of grid stability thanks to their rotating masses.
H2 still on the agenda, but future uncertain
Enthusiasm, once huge, for hydrogen as a potential route to clean power generation via gas turbines has dissipated somewhat in recent times – due to a combination of factors including high costs, demand uncertainties, regulatory issues, and lack of required infrastructure development – but several presentations touched on hydrogen based projects.
In Asia, in countries such as Japan and Korea, fuel is relatively expensive, so motivation to switch to low carbon fuel is still significant.
As described by Prof Toshinori Watanabe of the University of Tokyo, hydrogen appears to remain on the agenda in Japan, at least according to the 7th Strategic Energy Plan, issued by METI in February 2025. He noted that Mitsubishi, Kawasaki, and IHI are all actively involved in developing hydrogen and ammonia fuelled gas turbine technologies.
Nicolas Demougeot, Global Chief Engineer, PSM, outlined a PSM project at the Hanwha-Total Daesan refinery in Korea where a 1992 vintage 80 MW 7EA gas turbine, with modifications, has been successfully run on hydrogen. The mofications included installation of a FlameSheet combustion system, micromixer style pilot (employing AM) highly resistant to flashback, novel fuel delivery system and upgraded control logic. “Results were excellent and we went well beyond the original target of 50%vol hydrogen,” Demougeot said, with the project demonstrating sub 5 ppm NOx at baseload and 59.5% hydrogen.
He prefaced his description of the project with a reminder of the context: “Earth’s average temperature has been above the 1.5°C threshold for over 22 months, which has never happened before.”
He also pointed out that the idea of the hydrogen economy is not new, noting that, for example, British scientist J. B. S. Haldane talked about what he called the “hydrogen path” back in 1923.
Demougeot placed a particular emphasis on safety, observing that hydrogen is highly flammable, potentially explosive and needs to be handled with care. For the Daesan project, HAZOP studies were performed that led to the installation of 25 flammable gas detectors, a very extensive SHE (safety, health and environmental) plan was written, implemented and enforced, the site team went through regular training and drills, and there was a mandatory leak test of the hydrogen sub-station every time the trailers were connected to ensure a (close to) leak free system.
Turning to a European milestone project, Ertan Yilmaz of Siemens Energy gave an overview of the world-first HYFLEXPOWER collaboration, a joint effort involving Engie, Centrax, and National Technical University of Athens, as well as Siemens Energy, which demonstrated power-to-H2-to-power with 100% green hydrogen in an SGT-400 gas turbine employing DLE combustion. Interestingly, for all natural gas/hydrogen blends up to 100% H2, NOx was less than 25 ppmvd@15% O2.
A follow-up project, HycoFlex, aims to develop a retrofittable 100% H2 package for SGT-400 gas turbines that can be offered as a market ready product. There are also plans to scale the 100% H2DLE combustion technology platform developed as part of HYFLEXPOWER across Siemens Energy’s gas turbine portfolio.
Elsewhere in Europe, DLR, SINTEF, Norwegian University of Science and Technology and Ansaldo Energia are jointly investigating the use of hydrogen in the sequential combustion system employed in Ansaldo’s GT36 turbine. The project, called FLEX4H2, aims to develop and validate a safe, efficient and highly fuel-flexible combustion system capable of operating with any hydrogen concentration up to 100% H2, at H-Class operating temperatures, while still meeting emission targets without any use of diluents. The rationale for the project is that gas turbines are seen as important for future grid stability but need to burn fuels with low CO2 footprint like hydrogen.
Constant Pressure Sequential Combustor (CPSC) technology, as employed in the GT36, is considered to offer unique opportunities due to the ability of the 2-stage combustion system to achieve increased operational and fuel flexibility.
A presentation by Peter Griebel of DLR described results from a lab scale sequential combustor.
In the Netherlands, at its Moerdijk power plant, RWE, along with GE Vernova, has been looking at converting a 9FB gas fired turbine to hydrogen. This “lighthouse project” was the subject of a presentation by RWE’s Jappe Hoeben.
Early stage development work on the Moerdijk plan, which envisages connection (by 2032 ish?) to Gasunie’s proposed Dutch hydrogen network, suggests that the Moerdijk high hydrogen conversion (to 80+ vol %) is “safe, flexible and emissions compliant” but “challenges are identified on the upstream side of the value chain.” The availability of hydrogen at pressure, along with the supporting network infrastructure for transportation and storage, is described as “uncertain” and the conclusion from work done so far on the Moerdijk project is that “the current policy and subsidy development trajectory may not be sufficient to support deep decarbonisation via the use of hydrogen by 2030.”
HVO and methanol
A somewhat more rapid decarbonisation option for gas turbines would appear to be converting to HVO (hydrotreated vegetable oil). This is something that Uniper has been been pursuing for several years, as recounted by Uniper’s Jon Runyon in his presentation. Building on extensive testing, Uniper has now converted three OCGT sites in the Swedish disturbance reserve to commercial operation on HVO: Öresundsverket (2 x 63 MWe); Karlshamn (2 x 18.5 MWe); and Barsebäck (4 x 21 MWe). Conversion at a fourth Swedish disturbance reserve site (Halmstad, SGT5-2000E) is currently in progress.
The table above, presented in the paper by Runyon et al, shows, as the authors suggest, that “Uniper is not alone on the HVO journey.”
Among the attractions of HVO is that there is already experience with it as a drop-in replacement for fossil diesel in the transport sector and it can achieve 80-90% gas turbine lifecycle CO2 reduction today (equivalent to >90%vol hydrogen cofiring), according to Runyon et al.
Uniper experience shows that gas turbine performance is not hampered by using HVO, with “no immediate concerns that HVO will negatively impact on emissions compared with fossil gas, oil or diesel.” NOx emissions can be expected to be similar to fuel oil operation, while some emissions (eg, SO2, CO, and dust) should be significantly less.
Methanol also shows promise as an alternative fuel for gas turbines, as indicated in a presentation from Siemens Energy/Industrial Turbine Co/Net Zero Technology Centre/Proman, presenter Siemens Energy’s Jacob Rivera. This focused on testing with aeroderivatives (SGT-A05, SGT-A20 and SGT-A35) equipped with modified injectors and combustors. The tests were carried out at RWG’s gas turbine test facility and the Centrax generating set test facility.
Methanol’s compatibility with existing infrastructure, relative ease of transport and established handling and transport facilities, promise relatively short implementation lead times, Jacob Rivera et al suggest. Another major advantage is low NOx emissions thanks to methanol’s high heat of vapourisation and low adiabatic flame temperature (although the relatively low LHV requires more fuel flow to achieve a given power).
Overall, Rivera’s presentation concluded that methanol can be a low-lifecycle-CO2 and low NOx alternative fuel that is “relatively well suited to use as a gas turbine liquid fuel.” Also, required modifications are relatively simple for Siemens Energy aeroderivatives.
The carbon capture route
As well as alternative fuels, such as hydrogen, HVO and methanol, carbon capture offers another potential route for the decarbonisation of gas turbines and combined cycle power plants.
A presentation from SINTEF, University of Florence and Baker Hughes looked at how hydrogen assisted exhaust gas recirculation might benefit the capture process, while authors from the University of Mons explored “the economic tipping point between H2-based gas turbines and CCS-enhanced gas turbines.”
They believe there is a risk of both technologies becoming trapped in the ‘innovation valley of death’ and conclude, among other things, that “only a strong reduction in H2-price can make H2 based CCGT economic,” echoing sentiments expressed elsewhere at the conference.
They also find that, as far as their analysis goes, CCS-enhanced combined cycle plants, just like hydrogen fuelled GTs, fail to achieve a positive ROI.
It will be interesting to see how CCUS integrated with gas turbines and CCGT, currently appearing to be attracting growing interest, fares in the next couple of years, particularly in comparison to hydrogen and alternative fuels.
Looking ahead, IGTC 2027 will provide a very good opportunity to review progress.
