A future picture seems to be emerging that shows the very smallest range of aircraft powered by batteries; the possibility of batteries, hybrid, all-electric or hydrogen to power the small to mid-range; and even more efficient gas turbines in the larger range aircraft so we should expect to see a combination of solutions as the industry transitions to a more sustainable future for aviation.
Therefore, aero engines as we know them today, or very close derivatives, will still be required but it’s quite possible that they could be fuelled by sustainable aviation fuel or hydrogen. In the longer term gas turbines will continue to evolve and we see a combination of all these technologies turning it into an even more efficient system delivering even better performance. Our vision is a marriage of innovative technologies that will deliver a more efficient mechanical and electrical hybrid system that is potentially fuelled by hydrogen.
In a post COVID-19 world, where sustainability will be a priority, we will need to understand how hydrogen can be used in a wider roadmap to decarbonise our world, not just in aviation but in other forms of transport long-term technology developments.
Within our Power Systems Division we are already actively involved in several hydrogen projects, which are providing us with valuable experience. We recently announced a partnership with the recently established Daimler / Volvo JV to use their hydrogen fuel cells for stationary fuel-cell generators as CO2-neutral emergency power generators for safety-critical facilities such as data centres. They will offer emission-free alternatives to diesel engines, which are currently used as emergency power generators or to cover peak loads. These can also be used in microgrid solutions.
And our small modular reactor programme will generate zero carbon electricity, which can be used either to supply the grid directly or indeed to drive electrolysers to generate green hydrogen. The hydrogen can then be used as the energy carrier itself or further converted into sustainable aviation fuels.
Whilst there are great attractions to a hydrogen-based economy there are barriers to its realisation including: widescale adoption, production at scale, infrastructure investments, bulk storage, distribution and safety considerations. There is also the issue of how to create a simultaneous demand and supply for hydrogen technologies to ensure the scale up can drive the costs down.
If we want hydrogen to be a sustainability solution, we also need to look at the lifecycle of its production – there is very little truly “green” hydrogen being produced today. Although Rolls-Royce SMRs could be a zero-carbon form of production.
There is a public hunger for action on climate change to happen now rather than in the long term. SAF is ready as a response to that demand – there is no requirement to redesign aircraft. We now need to understand how hydrogen can be introduced to complement that in parallel. We also have to recognise that if there is a demand for people and cultures to globally connect again, then for the long-range market SAF is the only current option (65 per cent of fuel consumed on flights over 1,000nm).
So despite the hype, hydrogen powered aviation is no silver bullet. It will take a combination of different solutions, including SAFs, electric, hybrid and more efficient gas turbines, powering different missions and complementing one another, to help the industry reach its decarbonisation goals.