Mercedes Mullins
The aviation industry is facing a significant challenge in reducing its carbon footprint, which accounts for 2% of global carbon emissions. With fossil fuels set to run out, researchers and experts are exploring alternative fuel sources to power aircraft. Recent test flights using hydrogen or biofuels have been successful, but there are still obstacles to overcome before aviation can become carbon-neutral. The development of sustainable aviation fuels (SAFs) made from waste fats, plant sugars, and other sustainable sources offers a promising solution, with some airlines aiming to zero out carbon emissions by 2050. However, the slow rollout of SAFs and the challenge of designing lightweight and powerful batteries remain hurdles in the transition to sustainable aviation.
| Characteristics | Values |
|---|---|
| Electric planes | Electricity could be provided by fuel cells, which can be more energy-dense than batteries. However, batteries would need to be lighter and more energy-efficient to power long-haul flights. |
| Hydrogen-powered planes | Hydrogen is the most efficient fuel made from renewable energy. Hydrogen-powered planes have been successfully tested, but there are challenges to making hydrogen a standard fuel. |
| Biofuel | Biofuels can be made from ethanol, corn, sugarcane, waste fats, plant sugars, and other waste products. However, using food crops may not be sustainable due to environmental consequences. |
| Sustainable Aviation Fuel (SAF) | SAFs are "drop-in" fuels that can be easily incorporated into existing airport fueling systems, lowering carbon emissions by up to 80%. |
Explore related products
What You'll Learn
Hydrogen as a fuel source
Hydrogen fuel is being tested and used as a sustainable green fuel in the aviation sector. Hydrogen can be burned in a jet engine or another kind of internal combustion engine, or it can be used to power a fuel cell to generate electricity to power an electric propulsor. Hydrogen aircraft using a fuel cell design are zero-emission in operation, whereas aircraft using hydrogen as a fuel for a jet engine or an internal combustion engine are zero-emission for CO2 but not for NOx. The burning of hydrogen in the air leads to the production of NOx, but hydrogen combustion produces up to 90% less nitrogen oxide than kerosene fuel and eliminates the formation of particulate matter. Hydrogen's high specific energy means it would need less fuel weight for the same range, although this is offset by the added volume and tank weight.
Airbus has been working on hydrogen-powered aircraft since at least 2020, when it founded a joint venture with ElringKlinger called Aerostack. In 2023, the fuel cell demonstrator was powered on at 1.2 megawatts. In 2025, Airbus announced that hydrogen fuel cell technology had been selected as the propulsion method for its future aircraft. The company's ZEROe aircraft will feature an electric propeller propulsion system powered by hydrogen fuel cells, which transform hydrogen into electricity through a chemical reaction. The only byproduct of this reaction is water, meaning the process will be almost carbon-neutral as long as the hydrogen is made using renewable energy.
Airbus is not the only company working on hydrogen-powered aircraft. In January 2023, ZeroAvia flew its Dornier 228 testbed with one turboprop replaced by a prototype hydrogen-electric powertrain. In March 2023, Universal Hydrogen flew a Dash 8 40-passenger testbed with one engine powered by their hydrogen-electric powertrain. On 8 November 2023, Airbus flew a modified Schempp-Hirth Arcus-M glider, dubbed the Blue Condor, equipped with a hydrogen combustion engine for the first time, using hydrogen as its sole source of fuel. On 24 June 2024, Joby Aviation's S4 eVTOL demonstrator, refitted with a hydrogen-electric powertrain in May, completed a record 523-mile non-stop flight, more than triple the range of the battery-powered version.
While hydrogen shows promise as an aviation fuel, there are challenges to its commercialization. These include the lack of refueling stations, large production costs, and consolidated carbon market share.
Fossil Fuels vs. Biomass: What's the Difference?
You may want to see also
Explore related products
Sustainable aviation fuels (SAF)
SAFs are an alternative to fossil fuels and can be mixed with fossil jet fuel to reduce emissions. When produced from renewable feedstocks, SAFs emit the same amount of carbon into the atmosphere as was previously absorbed by its feedstock, thereby closing the carbon loop. This reduces emissions, significantly lowering the aviation industry's carbon footprint and dependency on fossil fuels. A specific batch of SAF can reduce emissions by around 80-85%, compared to fossil jet fuel over its entire lifespan, including production, distribution, transportation, and combustion. SAFs can also reduce other harmful emissions like particulates and sulfur by 90% and 100% respectively.
The ICAO Global Framework for SAF, LCAF, and other Aviation Cleaner Energies includes a collective global vision to reduce CO2 emissions in international aviation by 5% by 2030, compared to zero cleaner energy use. ICAO is working to facilitate SAF development and deployment through the four building blocks of this framework: policy and planning; regulatory frameworks; implementation support; and financing.
The ICAO ACT-SAF Series of events is providing comprehensive training to ACT-SAF Partners on a range of important SAF-related topics, including sustainability, policy, economics/financing, certification, and logistics. SAF Feasibility Studies are also being developed as part of the ICAO-EU assistance project "Capacity building for CO2 mitigation from international aviation".
The Evolution of Fossil Fuels: A Historical Perspective
You may want to see also
Explore related products
![RC Airplane,RC Plane, 2.4GHz 2 Channels RTF RC Aircraft with 3-Axis Gyro for Beginner Easy to Speedy Fly Glider Toys with 2 Extra Batteries [ 3 Batteries ] White](https://m.media-amazon.com/images/I/613o9A54CxL._AC_UL320_.jpg)
Electric planes
There are several advantages to using electric planes. Firstly, they are much simpler than jet engines as they contain one-tenth as many parts. They are also more cost-effective as electricity costs one-fortieth as much as jet fuel. Electric planes are also environmentally friendly as they produce no emissions.
However, the main constraint of electric planes is the weight of the batteries. Commercial batteries store about 50 times less energy per pound than traditional jet fuel. Therefore, about 35 tons of batteries would be needed to power a plane the size of a Boeing 737. Nevertheless, advancements in battery technology will greatly impact the trajectory of the commercial electric plane industry. Aviation startup Elysian has already created the E9X, a plane powered by electric batteries that can hold 90 people and travel up to 500 miles.
Some companies are focusing on using electric planes for regional services and targeting people who would typically drive for shorter trips. For example, United, the third-largest carrier in the US, plans to use electric planes to bring new services to small cities or provide a greater frequency of service.
Fossil Fuels: Reliable Energy Sources With Pros
You may want to see also
Explore related products
Nuclear-powered planes
Nuclear-powered aircraft have been a topic of interest for many decades, with the first studies and proposals emerging in the 1950s. The United States Army Air Forces initiated the Nuclear Energy for the Propulsion of Aircraft (NEPA) project in 1946, which was later replaced by the Aircraft Nuclear Propulsion (ANP) program in 1951. The ANP program focused on developing two types of nuclear-powered jet engines: General Electric's Direct Air Cycle and Pratt & Whitney's Indirect Air Cycle.
The NB-36H, a modified B-36 aircraft, became the world's first plane to fly with an operating nuclear reactor on board in September 1955. However, the reactor was not used to power the plane but rather to study the effects of radiation and collect data on shielding requirements for an airborne reactor. The NB-36H made 47 flights through March 1957, and the program was terminated by President Kennedy in 1961.
In 1957, the Air Force and the U.S. Atomic Energy Commission explored the possibility of using nuclear reactors to power ramjet engines. Additionally, the Oak Ridge National Laboratory successfully tested nuclear aircraft engines, with two shielded reactors powering two General Electric J87 turbojet engines to nearly full thrust. Despite these advancements, political decisions, and concerns about the urgency of the program led to its early termination.
More recently, in 2018, Russian President Vladimir Putin claimed that Russia had developed a nuclear-powered cruise missile capable of evading defences and hitting any target globally. While there is no publicly available evidence to verify this, it indicates a continued interest in nuclear-powered flight.
Local Sustainability: The Fossil Fuel Challenge
You may want to see also
Explore related products
Biofuels
However, there are concerns about the scalability of biofuel production. Ramping up production would require a significant amount of additional cropland, contributing to deforestation and competing with food production. As a result, some have argued that biofuels will not be able to provide the significant greenhouse gas savings needed to decarbonize jet fuel at scale.
Despite these concerns, biofuels are still seen as a viable option for long-haul flights in the future, possibly in combination with electrofuels. Breakthroughs in biofuel production could also help to reduce prices and increase sustainability.
Crude Oil and Fossil Fuels: What's the Difference?
You may want to see also
Frequently asked questions
Researchers are working on a range of alternatives to fossil jet fuel. Some test flights powered by hydrogen or biofuels have been successful. Hydrogen is produced by wind and solar farms and is the most efficient fuel that can be made using renewable energy. Other alternatives include liquid ammonia or liquid methane, electricity from fuel cells, and Sustainable Aviation Fuels (SAFs) made from waste fats and plant sugars.
SAFs lower carbon emissions over the fuel's life cycle by up to 80%, according to Boeing. They are also "drop-in" fuels, meaning they can be easily incorporated into existing airport fueling systems.
Each new fuel source has its own set of trade-offs. Some will require years of research and development, while others may have environmental drawbacks. For example, fuel made from food crops like corn ethanol may lead to excess water usage and deforestation.
In addition to new fuels, advancements in battery technology and aircraft design will be crucial. This includes improving efficiency through longer wings, slower flight speeds, and more efficient wing and propeller designs.
