Decarbonisation Technology August 2026 Issue

Value of hydrogen and ammonia fuel blends in gas turbines Study highlights the need for a system-level approach to decarbonisation, where fuel selection, turbine design, and emissions control are evaluated together

Tina Owodunni, Rodolfo Tellez-Schmill, and Michelle Wicmandy KBC (A Yokogawa Company)

G as turbines (GT) remain central to power generation globally, but their role is increasingly challenged by decarbonisation targets. The use of natural gas reduces carbon dioxide (CO₂) emissions by approximately 20% compared with power generation from liquid fuels (Amin & Fors, 2020) (Rasouli & Tellez-Schmill, 2022) . As decarbonisation targets tighten beyond what natural gas alone can achieve, alternative low- carbon fuels are being actively explored. The next step is less straightforward. What does it actually take to decarbonise a gas turbine? Can hydrogen (Goldmeer, et al., 2022) or ammonia (Pashchenko, 2024) deliver meaningful emissions reductions without introducing new operational constraints? In response to these decarbonisation objectives, major gas turbine manufacturers, such as Mitsubishi, GE, and Siemens, have extended their commercial gas turbine models to combust mixtures of natural gas and hydrogen. Hydrogen can significantly reduce CO₂ emissions when blended with natural gas. Most modern GT models can achieve a maximum hydrogen content of 75 vol%, depending on configuration and modifications, while some original equipment manufacturers (OEMs) are targeting higher hydrogen capabilities (Amin & Bjorneld, 2025) . This reflects broader industry development, where major OEMs are advancing gas turbine technologies capable of operating with increasingly high hydrogen content as part of decarbonisation strategies (Amin & Bjorneld, 2025) . Although low-emissions hydrogen currently represents a small share of supply globally, hydrogen is expected to play a key

role in decarbonising hard-to-electrify sectors such as power generation and heavy industry (IEA, 2024) . However, this introduces an important trade- off. The volumetric heating value of hydrogen is very small, around 10.2 MJ/Sm3, compared to natural gas (typically ranging between 33- 45 MJ/Sm3). The heating value by mass is larger, 120 MJ/kg, compared to natural gas, and consequently, hydrogen combustion requires a lower mass flow rate. The low volumetric heating value of hydrogen requires a more flexible design of the fuel supply system to the GT. The system can either be “ Although low-emissions hydrogen currently represents a small share of supply globally, hydrogen is expected to play a key role in decarbonising hard-to-electrify sectors ” designed to modulate the flow of natural gas to achieve changing GT loads. Alternatively, it can use a fixed hydrogen content in the fuel gas with corresponding changes in the fuel gas flow rate as GT loads approach design values. Another option under evaluation is the use of blends of natural gas with either blue or green ammonia (Pashchenko, 2024) . Compared with hydrogen, ammonia offers advantages in transport and storage (Menefee & Schwartz, 2024) and provides a larger heating value (13.4 MJ/Sm³ or 18.6 MJ/kg). When blended with natural gas, ammonia requires a reduced overall fuel volume rate for gas turbine operation compared to hydrogen-