UPDATE ON H2 PROGRESS TOWARD ZERO CARBON EMISSIONS

By developer • November 19, 2024
UPDATE ON XERO CARBON GOAL JDA Aviation Technology Solutions

Experts have proposed many paths to reaching the goal of Net Zero Carbon Emissions. Each option—operational, aircraft/engine design, energy sources and more—has risks and rewards. None has emerged as THE or even A SOLUTION. The array of pioneers testing and developing innovations that may reduce aviation’s environmental impact.  

Tracking how hydrogen and other initiatives are progressing has been a line of posts here:

Below are two enlightening technical articles about HYDROGEN’s movement towards offering practical, affordable and green source.

First, European Politico Reporter Tommaso Lecca makes 5 impressive points about H2’s future:

  1. Truly green H2 may be difficult to produce
  2. It gas of diatomic molecules and its density plus the weight of its container will limit the range of flights
  3. The existing infrastructure will have to be replaced at considerable capital cost
  4. Certification of the regional aircraft will be easier (performance) than the later long range models (prescriptive). Neither will be cheap.
  5. There is a question of whether H2 will contribute to CONTRAILS, a subject of some unsettled science.

The second paper by Cranfield University’s Dr. TAMÁS JÓZSA, not surprisingly, examines H2’s academic challenges. While his list is daunting, he makes an important overarching conclusion:

There are precedents in engineering for working in extreme conditions and extreme parameters, such as in space and subsea environments; and THERE IS CONFIDENCE THAT THE USE OF HYDROGEN WILL BE SAFE WHEN THE MATERIALS, EQUIPMENT AND STANDARDS HAVE BEEN ADOPTED WITH THE APPROPRIATE CARE

Here’s a brief precis of Dr. Józsa’s highlights:

  • In general, the storage, transfer, and combustion of hydrogen requires special care because of its highly explosive nature when confined and mixed with air (oxygen). Hydrogen has one of the widest flammability ranges and one of the lowest ignition energies among common fuels. Made up of tiny molecules, hydrogen is known for its DIFFUSION INTO ANY TYPE OF MATERIAL, causing different forms of structural damage to whatever material it might be.
  • The demand for professionals with hydrogen-related skills and expertise started to increase. Thousands, if not tens of thousands, of engineers will be needed with a specialist understanding of hydrogen in order to deliver the necessary infrastructure of production, transport, and storage, and to maintain standards of safety throughout day-to-day operations.
  • More widely, there is a need for academia and industry — where there is still only a relatively small number of experienced professionals — to pool their practical hydrogen knowledge and experience in order to train the next generation of engineers and develop the necessary specialisms.

And excuse a bit of an advertisement-

  • In March 2024, £69 million was invested into the creation of the CRANFIELD HYDROGEN INTEGRATION INCUBATOR (CH2i), the first major hydrogen technology hub tasked with demonstrating the potential of hydrogen as a net zero aviation.

Innovation is probably the most important and uncertain aspect of this pursuit of the Zero Carbon goal. These two insightful expositions fully document several risks. Tracking the resolution of these challenges is difficult because much of the work is being performed in proprietary campaigns. This Journal will try to keep  current with what’s public is allowed to see.

Hydrogen-Powered Airplanes Face 5 Big Challenges

Hydrogen could help make flying greener, but switching away from fossil fuels poses some hefty challenges

By Tommaso Lecca & E&E News

CLIMATEWIRE | BRUSSELS — The best way to cut greenhouse gas emissions from flying is to fly less — but that’s a nonstarter for the industry and millions of passengers.

Instead, the sector is hunting for a tech fix that would allow airplanes to keep flying while polluting less — and ONE IDEA IS TO USE HYDROGEN. But there are big questions over whether this is a workable solution.

Here are FIVE CHALLENGES facing hydrogen-powered aviation.

1. Sourcing clean hydrogen won’t be easy

Hydrogen can be very clean or very dirty — it all depends on how it’s produced.

Most hydrogen on the market today is so-called gray hydrogen, made by splitting natural gas — which emits a lot of CO2. Blue hydrogen captures those greenhouse gases, but it costs more and there are worries about where to store CO2. The RAREST, AND MOST EXPENSIVE, is GREEN HYDROGEN, made by using renewable power to split water.

“Hydrogen planes will only be as sustainable as the energy that powers them,” said Carlos López de la Osa, aviation manager with green group Transport & Environment (T&E).

“Most hydrogen for transportation is not zero emission today. It’s not green hydrogen,” said Val Miftakhov, CEO of ZeroAvia, a British-American manufacturer that aims to deliver its first hydrogen-electric aircraft with 40 to 80 seats by 2027.

2. Hydrogen could cut aircraft range

Hydrogen is the lightest element, but it has a much lower energy density than kerosene, meaning aircraft powered by it instead of fossil fuels would actually weigh more.

It can be burned with oxygen to create water, powering a jet, but it has to be stored in liquid form, which means installing high-pressure tanks that keep the highly flammable substance at temperatures below minus 253 Celsius. All that adds weight, cutting into range, cargo and passenger capacity.

Hydrogen can also be used to power a fuel cell, generating electricity to turn a propeller.

According to a 2022 McKinsey study, “with current aircraft designs, HYDROGEN AIRCRAFT COULD BE RANGE LIMITED TO UP TO 2,500 KILOMETERS,” which is the distance between London and Istanbul. Only “redesigning airframes and storage technology might unlock longer ranges without reducing the number of available seats.”

Destination 2050 — the European aviation alliance for creating net-zero air transport by midcentury, which brings together airlines, airports, manufacturers and navigation service providers — predicts that hydrogen-powered aircraft will be AVAILABLE BY 2035, but only “suitable for short-range intra-European routes.”

LINK to full article

That means they can’t be used for long-haul flights which Eurocontrol, the European air traffic management body, says are responsible for more than 50 percent of aviation’s CO2 emissions.

3. It’s going to be expensive

Today’s airports have been set up to refuel airplanes with fossil fuels; they’d have to be revamped to supply hydrogen instead.

“There’s no hydrogen at the airports today,” said Miftakhov. He’s convinced the solution will be to “make hydrogen on site, at the airports,” which will reduce transport costs.

In January, the California Energy Commission, the state’s energy policy agency, awarded close to $3.3 million to ZeroAvia to develop a MOBILE LIQUID-HYDROGEN REFUELING TRUCK that will refuel planes alongside kerosene at the Livermore Municipal Airport.

However, the scale of the challenge is daunting.

“We don’t know the full potential of hydrogen in aviation yet, and there are still significant challenges on the road to make it not only technically but also economically feasible,” said Francisco José Lucas, head of sustainable aviation at the Spanish energy multinational Repsol, referring to the difficulties of getting hydrogen to airports. “NONETHELESS, WE ARE SURE THAT IT IS A TECHNOLOGY WITH GREAT POTENTIAL IN THE MEDIUM AND LONG TERM.”

4. Red tape will be a problem

Aviation arguably has the toughest safety standards of any industry on the planet. That means switching to hydrogen will face very high regulatory hurdles.

“For aircraft with less than 20 passengers, the rules are performance based, and therefore would not require any adaptation” to hydrogen propulsion, said Janet Northcote, spokesperson for the EU Aviation Safety Agency (EASA).

But “for larger transport aircraft, the regulations are more PRESCRIPTIVE and these would not be appropriate for all aspects in their current form,” she said.

The agency does have something called a Special Condition, which allows for novel technologies and has been used for the Airbus A321XLR — an extra-long range airplane still awaiting certification.

But in the case of the XLR, that Special Condition applies to a new design for a central fuel tank, not for a novel way of powering flight.

Northcote said EASA is in touch with hydrogen plane developers through the agency’s pre-application services.

“The pre-application process helps them de-risk their projects and allows us to identify where current regulations may need to evolve,” she said.

5. Non-CO2 impact

After all the effort to convert airplanes from kerosene to hydrogen, even such green machines could still have a negative climate impact.

Recent studies show that about 50 percent to 75 percent of aviation’s climate impact is caused by non-CO2 effects — such as nitrogen oxide emissions or water vapor — that contribute to the formation of contrails. These white clouds left in the sky by aircraft may add to climate change if they persist long enough.

“There are still doubts about the climate impact of hydrogen aviation,” said Matteo Mirolo, a sustainable aviation expert at Breakthrough Energy, an organization founded by Bill Gates that is also investing in developing hydrogen aircraft.

“We still don’t know exactly the non-CO2 impact of hydrogen,” said Mirolo, adding that hydrogen-powered aircraft would, however, have “a positive impact, reducing pollution levels compared to fossil kerosene-powered aircraft, including particulate matter.”

T&E’s López de la Osa argues that cleaner-burning hydrogen engines mean contrails are LIKELY TO BE SHORT-LIVED. “Hydrogen combustion emits fewer particles where water vapor can attach,” he said.

To test that, Airbus is running a head-to-head comparison in Nevada by flying similar hydrogen and kerosene airplanes.

The aim is to “generate data to understand the differences, via flight testing in environments where contrails would form,” said Glenn Llewellyn, vice president of Airbus’ zero-emissions aircraft program. Results are expected by the end of 2024.

Reprinted from E&E News with permission from POLITICO, LLC. Copyright 2024. E&E News provides essential news for energy and environment professionals.

Comment: Addressing the hydrogen aviation skills and technology gap

Opinion

Hydrogen technology will be key to decarbonising a number of sectors – including civil aviation – but its safe and viable deployment presents a number of new and difficult challenges for engineers writes Cranfield University’s DR TAMÁS JÓZSA

Engineers are used to the idea of working with fuels and materials where there is a risk of fire but a relatively low risk of explosions. Until recently, in spite of the rapid development of hydrogen technologies, few people have been talking about explosion safety, especially in aviation. 

Hydrogen has been used for centuries in industries like mining, chemicals, and water — but not in the quantities, types, and conditions that are planned for civil aviation.

In general, the storage, transfer, and combustion of hydrogen requires special care because of ITS HIGHLY EXPLOSIVE NATURE WHEN CONFINED AND MIXED WITH AIR (OXYGEN). Hydrogen has one of the widest flammability ranges and one of the lowest ignition energies among common fuels. Made up of tiny molecules, hydrogen is known for its DIFFUSION into any type of material, causing different forms of STRUCTURAL DAMAGE to whatever material it might be. Using traditional metals for example, such as steel or aluminium, the hydrogen works its way into the lattice of the metal and causes it to become brittle over time, leading to cracking. With polymers using a carbon-fibre and glass-fibre tank with a coating inside, the hydrogen will penetrate through the lining and without additional care to the level of tank emptying and filling, the coating will buckle and ultimately fail.

Now, the need for higher energy densities for hydrogen to match traditional kerosene fuels means storage at high pressures and extreme temperatures (up to 10 bar and below -253 degrees centigrade) that present a new and difficult series of challenges for engineers. 

With the focus on hydrogen as a critical technology for long-term decarbonisation of global aviation, safety is suddenly high on the agenda. The commitment of the sector has been demonstrated, for example, by Airbus’ development of the ZEROe aircraft, which aims to be the first hydrogen-powered zero-emission commercial aircraft targeted for entry into service by 2035.

There are precedents in engineering for working in extreme conditions and extreme parameters, such as in space and subsea environments; and there is confidence that the use of hydrogen will be safe when the materials, equipment and standards have been adopted with the appropriate care

In April 2024, an Aerospace Technology Institute event series drew attention to the major challenges around adopting hydrogen-powered aviation based on roundtable discussions with the representatives of major stakeholders, such as Rolls-Royce, GKN Aerospace, the Health and Safety Executive, and BOC.

The events identified the following bottlenecks for scaling innovation: establishing test facilities, characterising material properties,  and  determining safe operating conditions. In other words, the industry doesn’t yet fully understand how hydrogen will interact with the conditions involved.

There are PRECEDENTS IN ENGINEERING for working in EXTREME CONDITIONS AND EXTREME PARAMETERS, such as in space and subsea environments; and there is confidence that the use of hydrogen will be safe when the materials, equipment and standards have been adopted with the appropriate care. Regulatory bodies like the EASA are working closely with manufacturers to develop new safety standards for hydrogen-powered aircraft, while collaborations like the Clean Sky 2 initiative are fostering innovation across the sector.

The DEMAND FOR PROFESSIONALS WITH HYDROGEN-RELATED SKILLS and expertise started to increase. Thousands, if not tens of thousands, of engineers will be needed with a specialist understanding of hydrogen in order to deliver the necessary infrastructure of production, transport, and storage, and to maintain standards of safety throughout day-to-day operations. 

In March 2024, £69 million was invested into the creation of the Cranfield Hydrogen Integration Incubator (CH2i), the first major hydrogen technology hub tasked with demonstrating the potential of hydrogen as a net zero aviation fuel. As part of this growing network of practical activity around hydrogen for aviation, the university is working alongside industrial partners to offer courses disseminating the state-of-the-art knowledge and experience of engineers working with hydrogen-related technologies.

More widely, there is a need for academia and industry — where there is still only a relatively small number of experienced professionals — to pool their practical hydrogen knowledge and experience in order to train the next generation of engineers and develop the necessary specialisms. In universities, for example, sophisticated computational modelling tools are available to play through hundreds of different scenarios to assess the particular risks around hydrogen use in different circumstances and in combination with different materials, gases and powders, as well as the potential impacts of an accident. Specifically, computational fluid dynamics can be used to design sensor placement for leakage detection, to model released gas propagation, and to design equipment for explosion protection.

With its zero emissions potential, hydrogen in both gas and liquid forms is going to play an important role in the green energy landscape. An evolution in engineering expertise will be essential to creating a very low risk environment in aviation, proving viability and safety for wider applications.

 Dr Tamás Józsa, Lecturer in Computational Fluid Dynamics, Centre for Computational Engineering Sciences, Cranfield University

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