Green Technologies to Fly High!

Sustainable aviation

A mile of highway will take you a mile. A mile of runway will take you anywhere.’ The statement best describes the extravagance and the beauty of air travel. Flying high is no more a dream but something the majority of us do on a regular basis, be it for business or leisure. Flying as a mode of transport has gained a lot more popularity with time being the essence of all and flights becoming more and more affordable. The first commercial passenger flight started sometime towards the fag end of the 1st half of the 20th century and the industry has bloomed and grown like anything since. Aircraft technology has evolved fantastically to suit the changing needs of the time and will keep on improving green technologies till they achieve a green air future.

Air travel has connected the world better than any other mode of transport known to mankind. It has brought a lot of ease in business, trade, and travel and bloomed the economy. The expansion of the aviation industry has made the world smaller making every corner of it accessible. However, this too has a dark side that involves global warming and carbon footprints. The increased popularity of air transport is also likely to strain the need for fossil fuels causing lasting damage to the environment. 

The aviation industry contributes to around 2.5% of the total carbon dioxide (CO2) emissions and 12% of the emissions by the transport industry. Although the share seems relatively small, it is likely to increase by three folds with air transport becoming the most preferred way of traveling. More than carbon dioxide emissions environmental experts have expressed deeper concerns regarding the jet contrail release, a white line seen trailing the aircraft. It is implicated in the formation of cirrus clouds that reflect terrestrial radiation and increase global warming. Moreover, the emissions from aircraft also consist of soot particles, nitrogen oxides, and other trace emissions that are harmful to the environment. As a result, the major airline companies are aiming to reduce emissions significantly by 2035 and attain net zero by 2050 by adopting new technologies. 

Let’s have a look at the technologies that are being employed to make air travel greener.

Sustainable Aviation Fuel

Sustainable aviation fuel, more commonly known as SAF, has been at the top of the list of measures to decarbonize the aviation industry. Although similar to the traditional jet fuel (fossil-fuel based), SAF has a unique chemistry that results in a significant reduction in carbon emission on burning. The fuel is made of sustainable feedstocks like cooking oil, non-palm waste oil, solid waste from the home, food waste, textile, and paper waste, etc. The SAF is produced using hydrocarbon via the process of hydrodeoxygenation. The fuel is purified and later mixed with traditional jet fuels. The SAF is being widely used to run aircraft around the world. Indian airlines are also following the sustainable path. Indigo has signed an agreement with the Dehradun-based Council of Scientific and Industrial Research-Indian Institute of Petroleum (CSIRIIP) to manufacture and deploy sustainable aviation fuel (SAF) globally. Back in 2018, Spicejet ran its flight on SAF (a blend of traditional fuel and biofuel from the Jatropha plant) for the first time.

Hydrogen-powered airplane

With the skyrocketing levels of GHG emissions (due to fossil-based fuels), the use of alternative fuels (zero emission fuels) for transportation is gaining quantum. Hydrogen fuel is proving to be an excellent choice for road transport and it is now being tried as a low-carbon fuel for the aviation industry. Similar to hydrogen-powered vehicles, hydrogen-powered aircraft would have a jet engine or internal combustion engine running on hydrogen or a fuel cell generating electricity to power the aircraft. Aviation giants Airbus and Boeing are aiming at introducing civil hydrogen-powered aircraft by 2035. Apart from the big airline companies, the UK-based aviation company ZeroAvia is planning to test a small 19-seat hydrogen-powered aircraft soon. Once the test is successfully completed, the company is planning to run several such flights in the UK as well as the US. The viability of hydrogen-powered aircraft engines has been tested by the Internation Council of Clean Transportation (ICCT), for two designs of liquid hydrogen combustion engines. The study showed that the accommodation of the hydrogen-powered engine would require some physical and technical modifications in the aircraft. The use of hydrogen-powered aircraft would be a major leap towards decarbonization of the aviation sector and take the load off of traditional fossil-based fuels. 

Small aircraft with electric engine

Electric cars are in bloom these days. The concept and design have been successfully imbibed and have been a huge success in modern society. The next step is to fly electric planes. The principle is similar to the electric car, the use of an electric propulsion engine. The first electric flight was tested sometime in the 18th century, however, the increased use of jet fuels sidelined the idea of electric flights. The changing climatic conditions and global warming have given a jumpstart to the research of electric and solar-based aircraft. Small aircraft with electric engines have been successfully tried and tested in the past. Tech companies are now experimenting with innovative ideas for big electric passenger aircraft. The base for these experiments is located majorly in Washington state, the Los Angeles area, Israel, Germany, and other parts of eastern Europe. There are around 215 different types of electric aircraft in use today and more are being made. 

Fuel efficiency improvement 

The innovations and ideas discussed above are still in their embryonic stages and their implementation on a large scale would require some time. As a result aviation companies are also looking at some immediate ways to modify the engine and plane to minimize fuel consumption and increase fuel efficiency. The commonly used modifications include the use of winglets (aerodynamic efficiency), a flexible navigation system, continuous climb, and descent operations to maintain an ideal flight path, using carbon-fiber composite instead of metal wings, blended wing body. These are some minor changes that can speed up the aviation industry’s journey toward decarbonization. 

Apart from the technical changes to the flight engines and aircraft, the airlines are also trying other means and ways to reduce the carbon footprints generated by the industry. The steps taken include buying offset carbon credits, investing in carbon capture and storage projects, minimizing paperwork, optimal utilization of ground facilities, etc.

These strategies are helping the airlines to adopt green flying practices. With the increasing awareness about deteriorating climatic conditions, more and more airlines are pledging to adopt greener air travel strategies. The situation looks quite hopeful for a greener air future

By Amruta Joshi

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