Sustainable Aviation Series - Biofuels in Aviation

From Turbojets Back to The Diesel Engine

Globalization has brought the world together in no small part thanks to the development of the aviation industry. From the first flight just over a hundred years ago, the aviation industry has grown to transport over four billion passengers every year. Aviation has reshaped the way we move, but it has also had a negative effect on the climate. In 2017, the aviation industry accounted for about 2% of global greenhouse gas (GHG) emissions, equivalent to 859 million tonnes of carbon emissions.

The International Civil Aviation Organization (ICAO), an agency of the United Nations with a mandate to ensure safe air navigation, is aware of the industry’s rapid growth and its impact on the environment. This led ICAO to commit to carbon neutral growth by the year 2020 through a Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA).

As of July 2019, 81 countries, representing over 75% of international aviation activity, intend to voluntarily participate in CORSIA, which aims to offset 2.6 billion tonnes of GHGs by achieving carbon neutral growth by 2020. In order to achieve this target, CORSIA is focused in three primary methods of reducing emissions: operational improvements, develop new aircraft technology and implement sustainable aviation fuels, also known as biojet fuels.

Source: International Civil Aviation Organization (ICAO)

Source: International Civil Aviation Organization (ICAO)

Biojet fuels are an attractive solution towards carbon neutrality because they have the potential to reduce lifecycle GHG emissions by up to 80 percent, repurpose waste, and are compatible with aircraft infrastructure (we don’t have to reinvent the airplane to fit massive batteries and electrical systems). However, we cannot help but be sceptical about ICAO’s expected role for biojet fuels to bridge the large gap between current carbon emissions and carbon neutrality.


Theoretically, biojet fuels provide an excellent opportunity to reduce GHG emissions but they have not seen major industrial incorporation in the global aviation supply chain.

One of the reasons for the sluggish adoption of biojet fuels in aircraft is the underperformance of these fuels in high-altitude environments where low temperatures of minus 30 degrees Celsius freeze conventional biofuels.

High energy density is also a requirement for any commercial aviation operation. Current technology only enables first generation biofuels (biofuels derived from food sources such as seeds) to be energy dense enough to commercially compete with fossil fuels. However, these first-generation biofuels are mired in controversy, as their use of land and food crops rise the cost of food products. Meanwhile, second and third generation biofuels (biofuels derived from sources such as biomass and algae) do not currently possess high enough energy density to operate competitively in the aviation industry.

Another factor limiting the adoption of biofuels in the aviation industry is the lack of supply chain infrastructure, driven by excessive upfront capital requirements. Numerous biofuel producers went bankrupt as they experienced technical difficulties raising money to finance the construction of mass biofuel production plants. Such is the tragic example of the biofuel company KiOR, which filed for bankruptcy in November of 2014.

Airlines have financial incentives to reduce their fuel costs but mostly face no penalties for their rising carbon footprints. The comparatively lower cost of conventional fossil jet fuels over biofuels has seemingly knocked biojet fuel out of the game for the time being - conventional fuel can cost up to five times less than biojet fuel. For example, in 2011 an Alaska Airlines flight paid $16 per gallon (USD) for biojet fuel, compared to about $3.15 (USD) per gallon of regular fossil fuel. In an industry where fuel accounts for a quarter of total flight costs, airlines look for every possible method to reduce fuel costs. For this reason, current aircraft flown on biojet fuel remains largely symbolic.

Canada’s Role in Developing Biofuels

Canada has taken its first steps towards aviation carbon neutrality.

In 2012, Air Canada operated two flights with biojet fuel. Three years later in 2015, Canada began the Bio-jet Supply Chain Initiative (CBSCI), a three-year collaborative project to enable a biojet fuel supply chain in Canada which aims to introduce 400,000 litres of biojet fuel into the shared fuel system at Montreal airport. The CBSCI project is well under way. In Earth day of 2018, Toronto’s Pearson airport joined the CBSCI by blending biojet fuel directly into its existing airport fuel supply system, this batch of fuel resulted in a reduction of 160 tonnes of CO2e. Current infrastructure does not exist in Canada to blend jet fuel with biofuel to create a biojet fuel blend, and consequently, this fuel had to be blended in California and transported by train to Toronto. This was performed to demonstrate the operational feasibility of biojet fuels in Canada’s jet fuel supply system.

Research is currently underway to develop denser and commercially viable biojet fuels. The Forest Products Biotechnology Bioenergy group at UBC, with the support of Boeing, Bombardier, Air Canada and WestJet, is looking into the GHG reduction potential of various technologies and feedstocks to produce biofuel. Their research program is also evaluating the GHG emission potential of a possible BC based commercial biojet facility.

The province of Alberta has developed a carbon offset Quantification Protocol for Biofuels to incentivize the generation of biofuels, in line with Canada’s agreement to collaborate on the CORSIA initiative, which requires airlines to offset carbon emissions through offset credits.

The carbon offsets are generated by biofuel producers. These projects are then verified by an eligible verification body to ensure they meet the requirements of the Biofuels protocol. Once verified, these credits could be purchased by airlines to help neutralize their carbon emissions. Through this cycle, airlines can purchase offsets to meet CORSIA 2020 carbon neutrality requirements while they help develop the biojet fuels that will power the future of aviation.

The Take-Off for Biojet Fuel

There is much work to be done for biojet fuel to take off as a potential solution to decrease carbon emissions from the aviation industry.

First of all, supply chains must be upgraded to allow efficient distribution of biojet fuel from manufacturer to aircraft. More research to develop biofuels with higher energy density and a low freezing point needs to be accelerated and implemented. Finally, the environmental costs of fossil fuels must be accounted when evaluating fuel alternatives in the aviation industry.

This article was the first in a series of aviation sustainability article. It served as an introduction to CORSIA and the role of biojet fuels in the battle against climate change. The following article will cover the role of Operational Improvements that the aviation industry is undertaking to reduce GHG emissions.