The aviation industry has revolutionised global connectivity, commerce, and travel, and has become indispensable to contemporary society.
However, this rapid expansion has had a significant impact on the environment, with aviation being a significant contributor to greenhouse gas emissions.
As the world confronts the challenges of climate change, the imperative to decarbonize aviation grows.
Aviation is one of the fastest-growing sources of greenhouse gas (GHG) emissions, which contributes to global climate change. It accounts for 2% to 3% of annual global CO2 emissions.
If the aviation industry were a country, it would be among the top 10 carbon-emitting nations in the globe. A round-trip flight from London to New York emits more carbon dioxide than the average citizen in 56 countries produces in a single year.
India has become the world's third-largest aviation market after the United States and China as a result of the proliferation of low-cost airlines, infrastructure development, rising disposable income, and the tourism industry.
In 2023-24, India's domestic and international air passenger traffic is expected to surpass 395 million. The number of domestic airport passengers in India is expected to surpass 700 million by FY2030, while the number of international airport passengers will reach 160 million.
Aviation turbine fuel (ATF), a principal aviation fuel, is a byproduct of the petroleum refining process.
Since 2005, the Indian aviation sector's greenhouse gas emissions have multiplied by 2.5 (25 million tonnes of CO2 equivalent), increasing at a compound annual growth rate of 7.34%.
According to the Sustainable Alternative Futures for India (SAFARI) model developed by the Centre for the Study of Science, Technology, and Policy, the number of aircraft passengers could quadruple by 2030 and increase by fifteenfold by 2050 compared to 2018 levels.
According to the SAFARI model, GHG emissions from aviation transport (including cargo) will increase by 3.6 to 3.8 times by 2030 and by 12.6 to 14 times by 2050 compared to 2018.
Sustainable aviation is not a one-size-fits-all solution; rather, it necessitates a holistic and multifaceted approach to comprehensively resolve the industry's environmental footprint.
Key components of this strategy include embracing technological advancements, operational efficiencies, and alternative fuels. To attain true sustainability, all phases of an aircraft's lifecycle must be considered, from production to disposal.
Electric Aircraft Electric aircraft hold tremendous potential for achieving zero tailpipe emissions and decreasing carbon footprints. However, weight restrictions and limited range pose substantial obstacles for long-distance flights.
Electric aviation requires additional research and development to improve battery technology and commercial viability.
Aircraft Powered by Hydrogen: Hydrogen-powered aircraft are also a potential low-carbon propulsion technology. While current hydrogen technologies offer cleaner emissions, they are not appropriate for long-distance flights.
Significant research and development efforts are required to make commercial aviation powered by hydrogen a reality.
Sustainable aviation fuels (SAF) are regarded as one of the most practical alternatives to conventional aircraft fuels. SAF is compatible with existing aircraft and infrastructure despite being derived from sources such as agricultural refuse and carbon capture.
However, limited production capacity and higher prices relative to conventional fuels have prevented widespread adoption.
United Kingdom (UK): The UK has taken proactive steps to decarbonise its aviation sector, including air space modernisation and consumer behaviour modification.
By including international aviation emissions in its carbon budget, the United Kingdom demonstrates its commitment to the temperature objectives of the Paris Agreement.
The United States (US) is committed to aircraft and technology advancements, as well as conducting extensive research on battery-powered and hydrogen fuel cell aircraft. Their Aviation Climate Action Plan outlines a comprehensive strategy to attain net-zero sectoral emissions by 2050.
Several European nations have taken substantial measures to reduce aviation emissions. France and Austria have implemented bans on short-haul flights when an equivalent train journey is available, thereby fostering more environmentally friendly travel options.
India will participate in the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA), with offsetting requirements anticipated to be applicable to India beginning in 2027.
India-based airlines have also begun implementing stringent efficiency measures and modernising their fleets with cutting-edge technologies and more fuel-efficient engines.
TaxiBot, a semi-robotic hybrid special purpose vehicle, has been in use at Delhi's Indira Gandhi International Airport for aircraft taxiing since 2019, allowing airlines to save 2.1 million litres of ATF by 2021.
Regarding the adoption of low-carbon fuels in the Indian aviation industry, some airlines have already utilised ATF–SAF blends for demonstration flights.
The Indian Institute of Petroleum, a division of the Council for Scientific and Industrial Research (CSIR, CSIR-IIP), has established a pilot facility in Dehradun for the production of SAF for flight testing by the Indian Air Force. SpiceJet's inaugural biofuel flight in the country was also powered by the CSIR-IIP production facility.
Recently, CSIR-IIP, SpiceJet, and Boeing have joined forces to investigate potential applications of SAF within the Indian aviation industry. In addition, CSIR-IIP is awaiting ASTM certification for the commercial production of SAF at a capacity of 15,000 litres per day (approximately 3,200 tonnes per year).
The recent (May 2022) amendment to the National Policy on Biofuels 2018 permits additional feedstocks for biofuels and the promotion of biofuel production in India under the 'Make in India' Programme, allowing India to be well-positioned in SAF production.
The decarbonization of the Indian aviation sector by 2050 requires a combination of strategies, such as fleet renewal with efficient flights, operational enhancements in ATM, and the utilisation of a SAF–ATF blend.
In addition, the widespread adoption of TaxiBots for air transportation service at Indian airports would significantly reduce greenhouse gas emissions.
In the meantime, research into electrification and hydrogen propellant is required to develop solutions for aviation. The government should provide adequate support for research and pilot studies on SAF production processes and diverse domestically available feedstocks.
Indian airlines have a proven track record of reducing ATF consumption by employing a more energy-efficient fleet.
The reduction of inefficiencies in the Indian aviation sector's current Air Traffic Management (ATM) system will be aided by international collaborations and the adoption of global best practises.
Taking into account costs, technological maturity, and feedstock, hydro-processing and alcohol-to-jet fuel are viable methods for the mass production of SAF in India to assure widespread deployment.
The primary feedstocks include used cooking oil, animal lipids, and other oils, as well as agricultural residues such as straw, husks, chaffs, and excess sugar molasses.
In addition, India must develop plans to attain a SAF–ATF blend target of 1.2% (including passenger and goods vehicles) by 2030.
This is consistent with the Clean Skies for Tomorrow Initiative's voluntary goal of conveying 100 million domestic passengers in India using a 10% blend of SAF by 2030. Numerous Indian airlines, terminals, and institutes participate in this coalition to facilitate the transition to net-zero emissions.
As air traffic demand increases, it will be difficult to maintain and enhance the effectiveness of the air traffic management system. Continued infrastructure investment is necessary to reduce petroleum consumption per flight.
While India has sufficient feedstocks for SAF production, efficient collection, segregation, and distribution mechanisms are lacking. Adopting sustainable agricultural practises is necessary to prevent negative environmental impacts.
The higher cost of SAF relative to conventional fuel is a significant barrier to its widespread adoption. Reduced production costs and commercial deployment support are required to make the SAF economically viable.
Delays in SAF Production Procedures: The lengthy certification and approval procedure for SAF production can impede the expansion of production capacity. In order to meet ambitious merging goals, it will be necessary to streamline these procedures.
Aviation decarbonization is an essential necessity for a sustainable future. As aviation continues to play a vital role in global connectivity and economic development, it must also be accountable for its environmental impact.
The aviation industry can pave the way towards a greener and clearer future through collaborative efforts, technological innovation, and forward-thinking policies.
By adopting sustainable practises and making conscientious decisions, the aviation industry can become more environmentally responsible. Only then will we be able to assure that the wings of progress will carry us into a sustainable future for future generations.