Ansaldo Energia and Equinor collaborate on 100% H2 gas turbine combustor17 December 2019
Sequential combustion, as incorporated in the GT26/GT36 technology acquired by Ansaldo Energia from Alstom, facilitates the use of high hydrogen – even 100% H2 – fuel for gas turbines.
Compared with natural gas the main challenge when combusting hydrogen combustion in gas turbines is its increased reactivity resulting in a decrease in engine performance for conventional premix combustion systems, says Ansaldo Energia, owner of GT26 and GT36 gas turbine technology. But thanks to the sequential combustion concept employed in GT26/ GT36 gas turbines, they can overcome this drawback, allowing the use of hydrogen in a low-NOx premix system.
Already today the H-class GT36 combustor can be operated with a hydrogen content in natural gas of up to 50% (by volume), according to Ansaldo, and recent full-scale high-pressure tests have shown the feasibility of operating at up to 70% hydrogen without power or efficiency derating, with “the possibility to burn up to 100%.” 
To further develop this fuel flexibility capability, Ansaldo Energia and Equinor have joined forces and signed a collaboration agreement. The purpose of this collaboration is to advance hydrogen combustion technology via full scale, full pressure combustor validation tests, with the aim of optimising for ultra-low NOx emissions, good operational flexibility and minimal engine derating at very high hydrogen contents.
Equinor, which is co-funding these hydrogen combustor tests, says it is “committed to long term value creation in a low carbon future”, in which clean hydrogen “as fuel for power production is considered one of the main pillars.” Equinor also describes itself as a world leader in carbon capture and storage, a precursor to producing CO2-free hydrogen from natural gas.
 M Bothien, A Ciani, J Wood and G Fru¨chtel, Sequential combustion in gas turbines – the key technology for burning high hydrogen contents with low emissions, Proceedings of ASME Turbo Expo 2019, GT2019-90798