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In 2021, under the impact of the new crown pneumonia epidemic, the global aviation industry has experienced unprecedented heavy losses for two consecutive years, and is also struggling to find a new development direction.
As the two major “engines” of the aviation industry, the United States and Europe have invariably brought forward the aviation industry’s emission reduction targets: it is clear that net zero emissions will be achieved by 2050.
Due to the cross-border nature of the aviation industry, international negotiations are bound to be involved. After establishing a new goal, Europe and the United States will immediately focus on promoting it globally...
From March 22 to 23, the first International Clean Aviation Forum will be held in Brussels, Belgium, with the theme of "Clean Aviation Takes Off".
How to fly cleaner has become a core issue in the development of the aviation industry.
The United Nations regards the realization of global net zero emissions by the middle of this century as the most urgent mission for all mankind.
In 2018, a movement called "Flight Shame" was launched in Sweden and quickly swept across Europe, as more and more people began to choose greener ways to travel.
The general trend, Hao Hao Tang Tang.
If the aviation industry cannot innovate and transform, it will be eliminated and downgraded, and a new round of technological revolution and global competition has begun.
Aviation decarbonisation imperative
Carbon emissions to be reduced by 50% by 2050 compared to 2005
The UN's Intergovernmental Panel on Climate Change (IPCC) report pointed out that the goal of net-zero carbon dioxide emissions by 2050 is essential to keep global warming below 1.5 degrees Celsius above pre-industrial levels.
Since the signing of the Paris Agreement in 2015, a global consensus has been achieved to achieve carbon neutrality as soon as possible, and it is a general trend for major industries to achieve net zero emissions by the middle of this century.
As an important component and support of global economic activities, the aviation industry is bound to change actively and act proactively.
Since 2007, the long-term aviation industry has begun to explore the emission reduction of the whole industry. Many civil aviation-related international institutions and organizations have formulated corresponding plans, the most important of which is the International Civil Aviation Organization (ICAO) adopted in 2016. The Carbon Offsetting and Reduction Scheme (CORSIA), which formed the first global industry emission reduction market mechanism, and the aviation industry became the first industry in the world to implement global carbon neutral growth measures by agreement of governments.
According to the plan, the carbon emissions of the global aviation industry by 2050 will be reduced by 50% compared with 2005.
In 2021, under the impact of the new crown pneumonia epidemic, the global aviation industry has experienced unprecedented heavy losses for two consecutive years, and is also struggling to find a new development direction.
At the same time, the European Union and the United States have successively set the goal of achieving carbon neutrality by 2050.
The European Commission proposed a "Fit for 55" regulation in July to ensure carbon neutrality by 2050.
The United States followed suit and released the "Long-Term Strategy Towards Net Zero Emissions by 2050" in November, announcing the time node and technical path for achieving the 2050 carbon neutrality goal.
As the two major “engines” of the aviation industry, the United States and Europe have invariably brought forward the aviation industry’s emission reduction targets: it is clear that net zero emissions will be achieved by 2050.
Due to the cross-border nature of the aviation industry, it will inevitably involve international negotiations. After establishing new goals, Europe and the United States will immediately focus on promoting them globally.
In October 2021, the Air Transport Action Group (ATAG), which represents the global air transport industry, urged ICAO Member States to support the adoption of a long-term emissions reduction target at the 41st ICAO Assembly in 2022, in line with industry commitments.
At the 26th United Nations Climate Change Conference (COP26) held in November 2021, 23 countries including the United Kingdom, the United States and France formed the "International Aviation Climate Ambition Alliance" and signed the "International Aviation Climate Declaration", aiming to strengthen the intergovernmental Collaborate to set ambitious long-term targets for international aviation emissions.
In particular, support for ICAO's adoption of ambitious long-term goals urges ICAO to make specific commitments to achieve net-zero emissions by 2050.
Meanwhile, the International Air Transport Association (IATA), whose membership includes 290 airlines, has backed the 2050 net-zero carbon emissions flight plan.
Turning to February this year, under the auspices of France, the rotating presidency of the European Union, 42 developed countries signed the Toulouse Declaration on Sustainable Aviation Development and Decarbonization in Toulouse, the European capital of aviation, calling on the world to take measures to achieve this by 2050. Aviation decarbonisation targets to curb global warming.
Countries such as Europe and the United States hope to trigger a chain reaction with this non-binding initiative to push for the adoption of a global air transport decarbonization commitment at the 41st ICAO Assembly.
The initiative is also supported by 146 industry companies including Airbus, Air France-KLM and Dassault.
All parties emphasized that international cooperation under the ICAO framework is essential to ensure fair global competition.
ICAO Council President Salvatore Sciacchitano, who attended the event, emphasized that despite the ongoing outbreak and its impact, governments and the aviation industry have made ambitious decisions to take practical actions to promote the decarbonization of international aviation.
All of the above will ultimately "sword" the ICAO Assembly to be held in September.
The organization is carrying out research and consultations on the Long-Term Global Target (LTAG) for CO2 Emission Reduction from International Aviation.
From the end of March to the beginning of April, the organization will hold a global aviation dialogue on this issue, and the relevant negotiation progress will be submitted to the LTAG high-level meeting, which will eventually be voted on at the September meeting.
Decarbonizing the aviation industry by 2050 will undoubtedly be an extremely ambitious goal. No matter what commitments and constraints ICAO ultimately makes, the decarbonization of the aviation industry is already on the horizon.
Aviation technology is brewing a sea change
To achieve aviation decarbonization, technological breakthroughs are the key
Although the aviation industry is not a super big player in carbon emissions, it is definitely a "difficult household" in carbon emission reduction. The main reason is that long-distance flights still rely significantly on fossil fuels. To achieve aviation decarbonization, technological breakthroughs are the key.
The French "Echo" believes that the current aviation industry is about to usher in the third aviation revolution.
The first aviation revolution was the successful test flight of the Wright Brothers' first aircraft in the early 20th century; the second revolution was in the 1950s, when the advent of the turbofan engine heralded the golden age of aviation.
So what exactly is the third aviation revolution?
Dr. Frank Anton, head of electric flight technology at Siemens in Germany, gave his answer without hesitation: electricity.
Anton pointed out: "Electric propulsion technology is the development direction of the aviation industry, otherwise there will be no future for the aviation industry." The Siemens team has preliminarily completed the design, development and flight test of the hybrid electric propulsion system.
In 2015, Siemens launched an electric aircraft motor, which weighs only 50 kilograms, but has a power of 260 kilowatts, achieving the first flight of the world's first 250 kilowatt-class electric aircraft.
In the future, through the continuous optimization of the power system and the advancement of battery technology, Siemens hopes to develop a hybrid aviation device that can meet 100 seats.
For their French counterparts, the answer to that question is also one word: hydrogen.
In January this year, the French Civil Aviation Research Council (Corac) published a study on the technical route for decarbonizing air transport.
The report believes that in the future, it is necessary to continuously increase the proportion of hydrogen-powered aircraft to achieve decarbonization of the industry.
In its planned roadmap, France can launch a new generation of short- and medium-haul aircraft in 2030, using reduced fuel consumption and biofuels to achieve carbon neutrality; short-haul hydrogen aircraft in 2035; medium-range hydrogen aircraft in 2045; by 2050 In 2018, hydrogen technology could contribute 29% to the total carbon neutrality of the aviation industry.
In a separate, more radical, joint European study, replacing fuel with hydrogen could reduce the climate impact of air transport by 50 to 70 percent.
Electricity and hydrogen are currently the two main propulsion technology R&D routes.
The French Montaigne Institute report pointed out that considering the energy density of storage batteries and fuel cells, the application of pure electric propulsion will mainly be small aircraft.
For larger aircraft, hybrid-electric propulsion can serve as a transition technology to full electrification.
Hybrid electric propulsion can be achieved by combining conventional engines in series or parallel with electric propulsion.
This concept has been used in the automotive industry for a long time.
Based on the current technology outlook, fully electric aircraft with more than 100 seats will be difficult to enter into service by 2050.
The small aircraft business of less than 19 seats is growing, but currently accounts for less than 1% of total global aviation emissions.
For medium- and long-range large aircraft, the only more realistic technology options appear to be hydrogen and sustainable aviation fuel (SAF).
The hydrogen propulsion here is different from fuel cells that rely on hydrogen to generate electricity. Hydrogen-propelled aircraft burn hydrogen as engine fuel.
At present, major countries in Europe and the United States regard hydrogen propulsion as the best candidate for decarbonization of aircraft, and it is also one of the main technical solutions that can be realized in 2035.
The advantages of hydrogen fuel are that the combustion temperature is high, the thermal efficiency of the engine can be improved, and it is zero carbon emission.
From the perspective of engine manufacturers, it is not difficult to replace fuel oil with hydrogen, mainly to solve the problem of high temperature resistance of materials caused by hydrogen combustion.
Even if adjustments are necessary, 90% of the engine will likely remain the same.
The main difficulty in choosing hydrogen is the storage problem on the aircraft. Under the same air load, the weight of hydrogen fuel is one-third of that of traditional fuel, but the volume of hydrogen fuel is four times that of fuel, which requires adjustments to the aircraft structure. .
And liquid hydrogen needs to be stored at a low temperature of minus 253 degrees Celsius. The material of the storage tank has high requirements for heat insulation, vibration and shock resistance, load bearing, and sealing. It is necessary to specially develop a liquid that can withstand thermal cycles and pressure cycles under the requirements of aircraft applications. Hydrogen storage tank.
According to the forecast of the French Institute Montaigne, in order to achieve the 2050 decarbonization goal, regional flights (mainly small aircraft with less than 100 seats), which currently account for about 3% to 4% of global aviation emissions, can be realized based on hybrid electric propulsion and hydrogen fuel cells. Decarbonization; short- and medium-haul flights (mainly medium-sized aircraft with 100 to 250 seats), which account for about 67% of aviation emissions, can rely mainly on hydrogen propulsion technology; long-haul flights, which account for about 30% of aviation emissions (mainly large passenger aircraft with more than 250 seats) ) also need to rely on sustainable aviation fuels.
In addition to propulsion technologies, decarbonization of aviation will require progress in incremental technologies such as improving aerodynamics, optimizing engine performance, and increasing digitalization.
Aviation giants are coming
European and American aviation companies speed up the development of hydrogen-powered aircraft
In Europe, in September 2020, Airbus launched the ZEROe zero-emission commercial aircraft project, and announced three hybrid hydrogen energy concept aircraft, using three types of engines: turboprop, wing-body fusion and turbofan, using combustion hydrogen as a Fuel, tentatively scheduled for a test flight of the prototype in 2025, and commissioning in 2035.
In February this year, 20 months after the announcement of the hydrogen aircraft project, Airbus announced a strong alliance with CFM International, a joint venture between GM and Safran. The two parties decided to jointly launch the hydrogen aircraft demonstration project around 2025.
The project aims to ground and flight test hydrogen-fueled engines in preparation for the launch of the first zero-emission aircraft in 2035.
The demonstration project will use the A380 test aircraft as a flight test platform, equipped with liquid hydrogen tanks prepared by Airbus' factories in France and Germany.
From 2026, Airbus will test hydrogen-fuelled engines during cruise on the A380.
In the U.S., in February, Pratt & Whitney was selected by the U.S. Department of Energy’s Advanced Energy Research Projects Agency to develop new, efficient hydrogen-fueled propulsion technologies for commercial aviation.
Pratt & Whitney's "Hydrogen Vapor Jet, Intercooled Turbine Engine" project will use liquid hydrogen fuel to greatly reduce aircraft contrails by recovering water vapor, enabling zero-greenhouse gas-emission flight and reducing nitrogen oxide emissions by 80% .
The semi-closed system architecture used in the project will have higher thermal efficiency than fuel cells, and overall operating costs may be further reduced compared to the use of "drop-in" sustainable aviation fuel.
This is the first direct collaboration between Pratt & Whitney and the Advanced Energy Research Projects Agency to support the aviation industry's strategic goal of achieving net-zero CO2 emissions from aircraft by 2050.
According to French newspaper Les Echos, Boeing still appears to have reservations about the feasibility of a hydrogen-powered aircraft by 2035, preferring to prioritize legacy models that run on alternative fuels.
In Russia, Rostec announced in July 2021 the launch of a program to develop hydrogen-powered engines for aviation and ground applications.
"The use of hydrogen fuel is one of the most promising areas of development in order to reduce the carbon footprint of the aviation industry," said Yuri Shmotin, chief designer of Russia's United Engine Corporation. "We are considering two main technologies: in improved gas turbines direct combustion of hydrogen fuel and the use of hydrogen fuel cells to generate electricity.”
Opportunities and challenges coexist for China
Zero carbon aircraft involves the development of new technologies, and everyone is on the same starting line
The French "Le Figaro" article said that many international aviation observers believe that the race for zero-carbon emission aircraft is a historic opportunity for China to finally enter the commercial aviation market.
Nicolas Bogran and Pascal Fabre, managing directors of global consulting firm AlixPartners, believe: "Zero-carbon aircraft involves the development of new technologies, and long-term investment China certainly has cards to play." As another expert concluded: " Everyone is on the same starting line."
In an interview with a reporter from Science and Technology Daily, Dr. Ye Weiming, head of the Air France Association of China, said: "In the research and development of hydrogen-powered aircraft, all countries are on the same starting line. This is an important opportunity for China." Ye Weiming said that China's aviation industry And the energy industry must seize the historical opportunity of the third aviation revolution and start as soon as possible.
China is still in the catching-up stage in the field of classic aero-engines, and it is suggested that China's aviation manufacturing industry should leapfrog to the direction of new energy technology as soon as possible and make a bold transformation.
Ding, vice president of the Air France Association of China and an Airbus R&D engineer, told reporters: "Airbus' zero-carbon large aircraft has a clear hydrogen energy technology route. For China's civil aircraft business, hydrogen fuel and other new energy aircraft structures and engines may be The opportunity to catch up with the curve is still a long-term challenge that needs to accumulate and accumulate. The essence of this new track for zero-carbon aircraft is the aviation manufacturing industry, which needs to be based on my country's model tasks and make steady progress. Efforts are made to narrow the gap.”
For more than half a century, Airbus and Boeing have continued to lead through technological progress, but under the change, the former "Big Mac" cannot guarantee continuous leadership in the future.
As for whether to choose hydrogen energy, Airbus and Boeing have parted ways, one is ambitious and the other is conservative.
Decarbonizing the aviation industry in less than 30 years will have to rely on disruptive technological breakthroughs.
Whether the aviation industry can be equipped with "hydrogen" in the future depends on bold innovation, as well as courage and vision.
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Hydrogen fuel and transportation
As a green, efficient and sustainable secondary energy, hydrogen has been used as fuel for a long time.
When the world's first internal combustion engine was put into use, it was not fueled by gasoline or diesel, but hydrogen.
In 1804, French and Swiss inventor Isaac de Riwaz began to try to replace steam with fuel with detonation properties after successfully designing several steam-powered cars.
His first experiment was to study the fundamentals of how the detonation and expansion of fuel in an engine cylinder propel the piston.
At that time, he used a mixture of hydrogen and oxygen to drive the internal combustion engine, and the experiment achieved initial success.
In 1807, he installed the experimental prototype engine on a four-wheeled carriage and drove the carriage for a distance, which earned the carriage the honor of "the world's first car powered by an internal combustion engine".
In the 20th century, auto companies, universities, inventors and hobbyists were further testing the viability of hydrogen-powered internal combustion engines.
In 1970, inventor Paul Diggs patented improvements to the gas-powered internal combustion engine, a design that would allow gasoline engines to run on hydrogen.
Today, hydrogen-fueled engines have demonstrated their ability to power vehicles ranging from sedans to buses.
For decades, the aerospace industry has used liquid hydrogen as a propellant in hydrogen-oxygen rocket engines to fuel space exploration.
Research on hydrogen as an aircraft fuel also has a long history.
Back in 1957, the National Advisory Committee for Aeronautics (NACA) used hydrogen as fuel to fly a Martin B-57 bomber for 20 minutes.
In 1988, the world's first experimental commercial aircraft using liquid hydrogen as fuel took off.
The Tu-155, developed by the Soviet Union, made about 100 test flights.
Today, more than 30 years later, the aviation industry is once again turning its attention to hydrogen-fueled commercial aircraft.