The global aviation industry accounts for about 2% of the global emission. Its share of carbon emission in the overall transportation sector is 12% which is expected to be doubled by 2050. When released at high altitudes, the aviation emission can be more severe, with impact going up to four times higher than emission released on the ground.
While Boeing and Airbus consider hydrogen a promising fuel to support the transition from fossil fuel in the long term, others are more optimistic and expect that fuel cell technology can disrupt aviation even sooner. Hydrogen has been emerging as a serious contender for aviation and offering several advantages over sustainable aviation fuel (SAF) and batteries.
Sergey Kiselev, Head of Europe at ZeroAvia, told H2Bulletin that hydrogen as a fuel in the aviation sector is driven chiefly by clean energy attribute and technological developments.
He explained that aviation has the potential to grow in ranks and eventually become a major contributor in the emitters’ league, so there is an urgency to address this issue before the situation exacerbates. Secondly, hydrogen production technologies and the cost associated with hydrogen fuel cells in the powertrain have been on a downward trajectory.
Over the last five years, electrolysers costs decreased by a factor of two while expected to fall around a factor of three over the next ten years. The falling production costs and advancement in fuel cell technology will underpin hydrogen applications in propulsion. There are pretty significant technological advancements in terms of the efficiency and power density of the fuel cells. ZeroAvia sees further improvement over the next five years in fuel cells’ power density as well as falling costs of the fuel cell stack. The recent technological advancements allowed the company to produce the hydrogen electric powertrain and powered its first commercial-sized aeroplane, which flown in September last year.
Safety is the utmost priority. Hydrogen is as safe to use as any other fuel, such as jet fuel. The hydrogen storage tanks went through quite a significant evolution and technological development over the last 15 years. There are several grades of storage tanks available, and they go through robust testing in terms of the burst pressure. They usually rated up twice of its maximum working pressure. He added, “So, in the context of safety, hydrogen storage tanks are pretty safe while there is a lot of work underway to make them lighter.” So, now the aim is to advance the technology so that the storage tanks become lighter while maintaining the safety features.
Sergey said that the conversions from jet fuel to hydrogen would also have cost benefits when considering operational costs of an aircraft, including fuel maintenance, crew, the basic ground handling costs etc. A 19 seat aircraft, for example, on direct operating costs, can achieve about 30% savings using hydrogen, assuming very conservative prices for hydrogen, which can be achieved today and with more saving going forward. This cost-benefit analysis makes hydrogen as a fuel in aviation more attractive. We have also made a similar comparison of the 70 seat plans and larger aircraft, and we still see the benefits of switching to hydrogen.
“Our roadmap includes the introduction of the hydrogen electric powertrain in the next three years. So, basically, at the end of 2023 or the beginning of 2024, we will start the commercial introduction of hydrogen electrical powertrain. First, it will be the retrofit of the existing 19 seat aircraft with pretty much one to one replacement of the stork engine with a hydrogen-electric power plant.” We foresee 42 to 70 seat plans to be converted over the next seven years.
H2Bulletin notes that engine overhauling typically happens after a few years. As a rule of thumb, it generally runs between 1,500 hours and 2,500 hours, or there is a calendar limit of 12 years.
So, in the beginning, we will be targeting the retrofit of the existing aircraft. So, when engines need to go through a significant overhaul or needs to be replaced, we can offer our powertrain. We anticipate that the hydrogen engine’s price, in addition to all the necessary modifications, including the cost of hydrogen tanks and installations, etc., will be very similar to the existing stork engine replacement. In some cases, the modifications which need to be made to the powertrain cannot be very significant.
Airport infrastructure is going to be airport specific. But in a nutshell, there are two basic models which airports can use. One model is to have similar storage facilities and refuelling provisions as what we have currently. For instance, the aviation fuel is transported through pipes or trucks to the airports’ storage tanks and then refuels the aircraft. So, a similar model can be replicated for hydrogen. The other model not only includes the storage and dispensing of hydrogen but also the production of hydrogen in situ at the airport, and that can be accomplished using electrolysers that are becoming cheaper. The cost of the electrolyser has been falling and would fall further in the coming years. This model is very attractive for some airports, especially where a significant amount of renewable power generation capacity available locally. The ultimate goal of using hydrogen in aviation is to move towards using green hydrogen, which is also what ZeroAvia goal is.
Given the high level of regulatory aspects, it is essential to have government support. Currently, the UK, Europe, the US are aware of the needs and taking important initiatives. We have finished the HyFlyer I program and started HyFlyer II program, secured £12.3 million (US$ 16.3 million) in government funding through the ATI Programme. We have enough funds to go through the development of the 19 seaters of the power train. He added, “We believe that small steps and small victories are important.”
There is also public perception which has to be changed with time. Mr Kiselev said that one of the downside risks to hydrogen in aviation is the lengthy timeline of technology development, given that it has to go through critical incremental steps.
This is part 4 of a 6-part series on hydrogen in the aviation sector that will run every Friday. Our next article will focus on HyPoint and its works on hydrogen in the aviation sector. We also asked HyPoint some questions, which we will discuss in our next article. If you have any questions or want to share your views, please feel free to contact us at firstname.lastname@example.org or +44 (0) 208 123 7812