By Bikram Vohra
Between noise abatement procedures and carbon emission restrictions and concerns, the world’s top power plant manufacturers have been put against the wall. Nonetheless, their determination and commitment to improving the standards on both counts and still maintaining the performance envelope on now generation aircraft has been commendable and the endeavour is ongoing. The official statement of fact is explicit: Over the years turbine engines have incorporated increased turbine inlet temperature, increased compressor pressure ratio, increased bypass ratio, improved fan and nacelle performance, reduction of noise and emissions and improved reliability. That is saying a lot. In much the same tone the standard statement states new engines will incorporate new aerodynamic designs, materials, coatings, combustion and cooling technology, and improved integration between the engine and airframe. These engines will cut fuel consumption, lower emissions of NOx and reduce the noise footprints 75%.
All this could become superfluous if an alternative to fossil fuel is found.
The hunt for such alternative fuels or what is known now as sustainable aviation fuel is now very serious business. SAF, as it is commonly known, is derived from sustainable feedstock and produces a dramatic reduction in emissions. SAF is made from waste oils from animals or plants; solid waste from homes and businesses, such as ‘packaging, paper, textiles, and food scraps that would otherwise be sent to landfills,’ as per the description.
However, this is a temporary stopover on the journey to total cleanliness or what Airbus in its research calls Zero emission. Is this even possible? Airbus has a current programme that says yes. To quote: At Airbus, we have the ambition to develop the world’s first zero-emission commercial aircraft by 2035. Hydrogen propulsion will help us to deliver on this ambition. Our ZEROe concept aircraft enable us to explore a variety of configurations and hydrogen technologies that will shape the development of our future zero-emission aircraft.
It is difficult to provide a more cogent explanation than what the European aircraft manufacturer has promised. All three ZEROe concepts it is working on are powered by hydrogen combustion through modified gas turbine engines. Liquid hydrogen is used as fuel for combustion with oxygen.
In addition, hydrogen fuel cells create electrical power that complements the gas turbine, resulting in a highly efficient hybrid-electric propulsion system.
Airbus goes on to say that in 2022, it launched the ZEROe demonstrator with the aim to test hydrogen combustion technology on an A380 multimodal platform. It worked. Now, the plan is to engage in future ground and flight testing and “achieve a mature technology readiness level for a hydrogen-combustion propulsion system by 2025.”
These environmental advantages are the spearhead of the enthusiasm that is marking the revolution and generating interest in other research companies. In general, aviation experts believe this option is a probability and well within the realm of changing the dynamics completely.
It is now an acceptable premise that hydrogen-powered planes flying in Europe’s airspace gained credibility after Airbus’ announced in 2020 that zero-emission commercial aircraft based on hydrogen could enter service by 2035.
In the interim, the US government has provided another boost to the hydrogen concept by the signing of a second deal between the USAF and the woman controlled Hydroplane Company. This contract will allow the company, in unison with the University of Houston, to demonstrate an engineering model hydrogen fuel cell based powerplant in a set of ground and flight demonstrations.
Hydroplane plans to fly its demonstrator aircraft in 2023. Dr. Anita Sengupta, CEO of Hydroplane and a former NASA propulsion engineer is quoted as saying, “We are excited to be a part of the prestigious and highly competitive USAF Agility Prime Program, and a testament to the unique innovation we bring to emission-free electric aviation with regional range. Hydroplane will offer the general aviation and vertical lift markets zero-emission electric propulsion that outperforms batteries in range, endurance, payload, and operational efficiency. Once proven in this arena, we will expand the technology to regional aviation with increased operational capability.”
What makes these initiatives even more exciting is that everyone is getting on the same page. EUROCONTROL, the organisation that provides a platform for civil-military aviation coordination in Europe and delivers quality training in air traffic management (ATM) has published a think paper on the subject and made an assessment over cutting emissions by 55% in 2030 compared to 1990 levels and if successful, what that would mean for European aviation
The paper shows that a 55% reduction in CO2 emissions by 2030 is achievable in all three scenarios, but its success depends on the Market Based Measures, mainly via the EU Emissions Trading System (ETS). The ETS is slated to make an 83% contribution to the net reduction.
Of immediate relevance is the estimated cumulative extra cost to the aviation industry over the period 2022–2030 of these decarbonisation measures. The shift will amount to €62 billion. That is just for Europe.
Hydroplane’s 200 kW modular solution is designed to replace existing combustion powerplants in today’s existing single engine and urban air mobility platforms, while simultaneously delivering a significant improvement in range, endurance, and payload over the battery-powered equivalent.
Hydroplane hydrogen fuel powerplants have tangible benefits:
- Electric aviation with regional range
- No battery charging required
- Zero carbon emissions
- Low operations and maintenance costs
- Reduced noise signature
- To be certified under FAA Part 23, direct replacement for piston power plants with competitive range and installation cost
At Hydroplane the team defines itself as consisting of seasoned space program, aviation, and automotive engineers, and fuel cell technologists uniquely skilled and experienced in developing innovative new technology for NASA, SpaceX, Blue Origin, Virgin, Boeing, and academia.
Dr Sengupta says that at the plant programme-trained engineers are developing a hydrogen fuel cell powerplant, the key technology to decarbonize aviation. Hydroplane is a winner of two U.S. Air Force Agility Prime contracts to develop the novel technology for a range of government and commercial aviation applications.
There is a fair amount of logic to all this seeing as how cars are already well down the road to hybrid fuels including electricity. We are experimenting with natural gas, fuel cell vehicles powered by compressed hydrogen. Hyundai Motor recently announced the deployment of hydrogen fuel cell electric heavy-duty trucks, the world’s first mass-produced truck with hydrogen as fuel. With Honda’s Clarity Fuel Cell, and Toyota’s Mirai making tracks along with Hyundai’s Nexo Fuel Cell SUV, the cars are well ahead.
So why shouldn’t the same hold good for aircraft.