Introduction
The aviation industry is one of the global sectors looking to alter the problem of climate change. Aircraft contribute significantly to climate change through the significant emission of greenhouse gases during the combustion of fossil fuels. Therefore, as a way of achieving net-zero carbon emissions by 2050, aviators are seeking to use hydrogen technology for aircraft propulsion. Hydrogen from renewable sources emits zero-carbon gas, thus being the most promising method to achieve the net-zero goal.
This essay critically evaluates hydrogen as an alternative propulsion producer and its impact on the aviation industry. The paper synthesizes arguments regarding how hydrogen generates propulsion advantages and disadvantages for airlines and airports to ensure sustainability. Using hydrogen to generate propulsion despite various challenges is beneficial because it helps eliminate carbon emissions in the aviation industry to achieve the net-zero emission goal.
Term Definitions
The following are definitions of key terms and phrases used in the paper as they apply to the aviation industry. Propulsion in aviation produces a thrust or force to push or lift an aircraft from the ground (Yusaf et al., 2022). Contrails are trails of line-shape clouds in the form of ice particles created by changes in air pressure or airplane engine exhaust and are visible behind the craft (Yusaf et al., 2022). Turbulence is unstable air movement that changes wind direction or speed, causing shaking or a ‘jump’ on an airplane (Yusaf et al., 2022). Finally, a gas turbine is an internal combustion engine that spins pressurized gas to produce energy for an aircraft.
The Use of Hydrogen Technology in Aviation
Therefore, hydrogen technology can be used to produce propulsion in place of fossil fuels. The aviation industry promises to use hydrogen fuel cells to generate electricity by combining oxygen atoms and hydrogen. According to Petrescu et al. (2020), hydrogen, when put in an electrochemical cell similar to a battery, absorbs oxygen to generate energy, heat, and water. A fuel cell functions by having a fan move gaseous hydrogen from a liquid container, mixing it with air (Petrescu et al., 2020).
The hydrogen moves through a platinum screen, losing electrons to produce electricity and emitting heat and water (Petrescu et al., 2020). The produced energy in fuel cells is used to ignite the aircraft’s combustion engine. That way, similar to fossil fuels, hydrogen is combusted to produce electricity to propel the aircraft.
Advantages
Reduction of Aircraft Emissions
Arguably, hydrogen technology for propulsion brings many advantages to airplanes and the general aviation industry. The most critical benefit is the elimination of carbon gasses contributed by aircraft to the global percentage of emissions. The industry emits at least 900 million tons of carbon dioxide, or between 2% and 2.5% of global emissions (Petrescu et al., 2020). Although the industry contributes to such a small amount of emission, zero emission will significantly alter the effects of climate change.
The use of hydrogen also reduces the emission of nitrogen, thus improving the quality of the air. If all the airlines can adopt the use of hydrogen for fossil fuels, it will be possible for the industry to attain net-zero carbon emissions by 2050. That way, the aviation industry will be socially responsible for ensuring a sustainable environment.
Additional Atmospheric Improvements
In addition, hydrogen-powered airplanes can eliminate persistent contrails and turbulence. According to Yusaf et al. (2022), persistent contrails make particular atmospheric regions impassable and cause irregular jet movement. Craft engines emit a variety of products, including carbon and water, which at cold temperatures condense to form contrails and further cause turbulence.
Using hydrogen instead of fossil will ensure there is no carbon emitted, thus eliminating the chance of contrails created using carbon. However, Petrescu et al. (2020) suggest that contrails work with other environmental factors to cause aviation-induced cloudiness, which may make an area impassable through a craft; hence, eliminating carbon may not stop the cloudiness. Arguably, the contrails worsen the condition of cloudiness, but eliminating them will reduce the levels of fog, thus making it easy for the airplanes to move and minimizing the chances of turbulence. Consequently, the aviation industry will have created a better travel experience with minimal cloud-induced cloudiness and turbulence.
Disadvantages
Storage Challenge
Conversely, using hydrogen has the disadvantage of volumetric density, requiring more storage space in the aircraft. According to Min (2023), liquid hydrogen is significantly lighter than the plane fuel used by jets and has a volumetric density four times higher than jet fuel. In other words, the liquid hydrogen requires four times more volume on the jets, thus posing storage problems. However, the study by Bauen et al. (2020) shows that some airlines are already using hydrogen successfully with minimal storage issues.
The explanation for this contradiction is that these airlines have created new models of airplanes that are hydrogen-efficient in terms of volumetric density. The standard fuel models of aircraft are incompatible with hydrogen technology in terms of storage volume. Hence, an airline wanting to venture into the hydrogen-powered aircraft sector must be ready to build a new model. Therefore, the issue of volumetric density will slow the adaptation of hydrogen-powered airplanes in the aviation industry.
Higher Fuel Expenses
Another disadvantage of using hydrogen is that it is more expensive than jet fuel. Hydrogen is collected from renewable means such as biomass, wind power, and geothermal, which is produced in small quantities (Yusaf et al., 2022). Mr Llewellyn, a UK airline official, says there “needs to be a massive increase in the amount of renewable energy available and the amount of sustainable aviation fuel available” (Bauen et al., 2020, p. 274). Only a few countries have joined the hydrogen-based ecosystem formulated to find ways to produce safer energy.
As long as the quantity of hydrogen produced is low, the airlines using hydrogen technology to replace fuel can only operate a few aircraft. Therefore, nations adopting safe energy for aviation must work to increase renewable hydrogen production (Bauen et al., 2020). Consequently, until there is adequate production, the cost of hydrogen will remain high compared to that of fuel.
Infrastructure Implications
Furthermore, the adoption of hydrogen-based aircraft will push for the expansion of airports. According to Bruin (2022), liquid hydrogen requires more storage space in the plane and fueling stations. The current airports only use small spaces to store fuel because it has lower volumetric density; hence, they will need expansion for the airport fueling stations to store enough hydrogen. Airlines that will be having aircraft using fuel and hydrogen-based will need to have separate airports for each model.
Building new, expanding, or rebuilding airports will significantly cost the airlines and the aviation industry. The cost of switching to the new technology is already high and will grow higher upon expanding the airports. Consequently, the concerned airlines must be willing to spend more on developing airports; otherwise, the transition will be impossible.
Safety Benchmark Requirement
The last limitation of using hydrogen to generate propulsion is that hydrogen crafts must achieve similar or better safety levels than today’s kerosene-based planes before flying. Airplane safety is essential for both an airline and travelers. According to Bauen et al. (2020), hydrogen-powered jets will be more costly to maintain than those using fuel.
Fuel aircraft face severe safety issues, making maintenance high (Petrescu et al., 2020). However, with the high cost of hydrogen, securing the aircraft will only increase the costs. Since the hydrogen-powered planes will be assuming new models, they will also require increased safety measures. The problem with this requirement is that safety will have no adequate history to compare; hence, it might become chaotic.
Conclusion
In conclusion, using hydrogen to propel aircraft will eliminate the carbon emissions caused by the aviation industry, thus favoring the global climate. Hydrogen, as a renewable energy source, is used in fuel cells to generate propulsion where its production process or usage emits zero carbon gasses and no noise pollution. This technology works better than the combustion of fossil fuels by eliminating the possibilities of contrails and turbulence.
However, the application of hydrogen is faced with many challenges, making it difficult to adapt. The incompatibility of hydrogen with aircraft using fuels makes adapting it harder. Airlines must create new airplane models to conform to the weight of hydrogen. The cost and quantity of hydrogen produced today pose additional problems because increased costs mean only a few companies will adopt the technology in the next few years.
Reference List
Bauen, A., Bitossi, N., German, L., Harris, A. and Leow, K. (2020) ‘Sustainable Aviation Fuels: status, challenges and prospects of drop-in liquid fuels, hydrogen and electrification in aviation’, Johnson Matthey Technology Review, 64(3), pp. 263-278.
Bruin, A. D. (2022) Fuel cell and hydrogen technologies in aviation. London: Johnson Matthey.
Min, R. (2023) Successful test flight of hydrogen-powered plane give sustainable aviation lift. Web.
Petrescu, R.V.V., Machin, A., Fontanez, K., Arango, J.C., Marquez, F.M. and Petrescu, F.I.T. (2020) ‘Hydrogen for aircraft power and propulsion’, International Journal of Hydrogen Energy, 45(41), pp. 20740-20764.
Yusaf, T., Fernandes, L., Abu Talib, A.R., Altarazi, Y.S., Alrefae, W., Kadirgama, K., Ramasamy, D., Jayasuriya, A., Brown, G., Mamat, R. and Dhahad, H.A. (2022) ‘Sustainable aviation—Hydrogen is the future’, Sustainability, 14(1), p.548.