Bio-Fuel Technology — Future of Power

With the growing alarm and awareness of depleting fossil fuels and concerns regarding the environment, the market for alternative fuels for the aviation industry is expected to grow significantly

Issue: 1 / 2018By A.K. SachdevPhoto(s): By United Airlines

Inarguably, an aircraft’s most crucial constituent is its power plant. Since the first heavier-than-air flight by the Wright brothers, power plant technology has evolved dramatically and, in recent years, the pace of advancement has been accelerating. The materials used and the design progression have ensured that each successive model is an improvement in terms of thrust produced. However, one area in which original equipment manufacturers (OEMs) of power plants have not been able to make significant advancements is the fuel used. Fossil fuel remains the main source of energy for power plants although in recent years, there have been notable intent and endeavour towards replacement of the fossil fuel. Two motivations appear to have been the impellors in this direction: firstly the realisation that fossil fuels are irreplaceable and finite and need to be substituted by alternative fuels and secondly, the stimulus of reducing the environmental effects of fuel combustion and the resultant pollutants discharged into an already sullied atmosphere. Bio-fuels are the alternative fuels that the aviation world is looking at expectantly, but, while there is adequate advancement in bio-fuel technologies to nurture hope of bio-fuels edging out fossil fuels in the future, even the most optimistic view does not envisage the change to occur in the immediate future. This article looks at bio-fuel technologies to assess whether and when it could occur.

The Basics

Aviation industry’s commitment to reducing Greenhouse Gas (CHG) emissions along with the burden of increasing oil prices, is forcing it to look for sources of renewable and affordable energy. Aviation is a type of transportation for which traditional bio-fuels such as bio-ethanol and bio-diesel, do not fulfil the specific requirements. Hence the need to refine biofuel research and fine tune it to aviation requirements.


Bio-fuels are derived from biological sources (animal fats or oils extracted from vegetables) and can include aviation fuels suitable for aircraft engines of three broad categories namely piston engines, turboprop engines and jet engines. The bulk of requirement for aviation fuel is for the highly thirsty jet engines which consume huge quantities of fuel. Replacing or supplementing jet fuel with suitable bio-fuel would thus result in substantial savings of cost as also would help in cutting down undesirable emissions from jet engines. The technology associated with this is ‘white’ biotechnology which employs natural processes (basically use of enzymes) for industrial manufacturing. In contrast, red biotechnology is related to medical and pharmaceutical products while green biotechnology is relevant to agriculture. White biotechnology is considered a major technology of the 21st century inasmuch as it offers advantages over traditional chemistry through lower energy costs associated with its processes, elimination of complex synthetic methods and exploitation of renewable and sustainable resources.

The American Society for Testing and Materials (ASTM) has certified four different technological routes for production of biojet fuels. Gasification through the Fischer-Tropsch method (FT), using municipal solid waste (MSW) or woody biomass as feedstock was certified by ASTM in 2009. Hydroprocessed Esters and Fatty Acids (HEFA bio-jet), using oleochemical feedstocks such as oil and fats was certified by ASTM in 2011. Certification for Synthesised Iso-Paraffinic fuels (SIP), formerly known as the direct sugars-to-hydrocarbon route (farnesane) came in 2014 while Alcohol-to-jet based on isobutanol (ATJ), certified in 2016.

Currently, HEFA bio-jet holds the lion’s share of available commercial volumes of bio-jet fuels and a number of commercial scale facilities can produce it. However, the same process also creates renewable diesel (HEFA-diesel), for which there is a larger market and higher profit margins. Understandably, production is tilted towards HEFA-diesel and away from HEFA-jet. HEFA-diesel is also known as green diesel or hydro-treated renewable diesel. The operational capacity of the world’s current HEFA facilities is estimated to be about 4.3 billion litres per year. Even if all of this capacity were to be directed to produce bio-jet, the total supply would still amount to less than 1.5 per cent of the world’s jet fuel requirements. Although bio-jet biomass through gasification and subsequent FT conversion is not yet a commercial activity, it is expected to pick up momentum. Meanwhile, the development and deployment of bio-jet fuels, primarily HEFA bio-jet, is progressing from single demonstration flights by airlines and OEMs to multi-stakeholder supply-chain initiatives including equipment manufacturers, airlines, fuel producers and airports.

The Economics

The cost of producing bio-jet fuel is the single major reason for the current miniscule size of its availability and usage. HEFA bio-jet fuel continues to cost much more than fossil derived jet fuels. Palm derived bio-fuel costs nearly double the price of fossil based fuel. Moreover, the motivation for producing diesel fuels outweighs that for jet fuels as most governments subsidise the former due to its major contribution to national economy while jet fuels are not viewed as a necessity. The view that those who can afford air travel can afford to pay the higher price of fossil fuels, is also a factor that possibly inhibits a faster growth of bio-jet fuels. The International Civil Aviation Organisation (ICAO) has reached an international agreement on a global market-based measure (GMBM) scheme that aims at reducing aviation-derived carbon emissions through offset incentivisation. However, implementation is not expected to begin until 2021 and emissions from aircraft belonging to some member nations, especially the developing ones, are unlikely to be meaningfully regulated in the near future. While carbon offsets will contribute to global emissions reductions, the role they will play in furthering the cause of bio-jet development is a bit doubtful unless comprehensive and strict policy guidelines related to bio-jet production and consumption are put into place by member nations as well as ICAO.

There is also the problem of a debate that frequently becomes loud about feedstock versus bio-fuel production. This debate serves to slow down the pace of bio-fuel progression. Nonetheless, a significant historic flight took place in January this year when the world’s first US-Australia bio-fuel flight on a Qantas Boeing 787 Dreamliner took off filled with 24,000 kg of mustard seed-based, blended fuel. It flew from Los Angeles to Melbourne, using bio-fuel extracted from a mustard seed Brassica Carinata extracted through a process developed by Agrisoma Biosciences, a Canadian agricultural technology company.


Civil aviation accounts for a substantial amount of the total energy consumed in transportation annually. With the growing alarm and awareness of depleting fossil fuels and concerns regarding the environment, the market for alternative fuels for the aviation industry is expected to grow significantly in the near future. Bio-fuels are the leading edge of this growth as far as aviation industry is concerned. Over the years, various countries have been experimenting with bio-fuels in the form of blended fuels i.e. bio-fuel and jet fuel in order to curb their emission rates and possibly cut costs in the long run. Favourable government norms are expected to aid this high growth rate. The key players of global aviation alternative fuel markets are Solazyme, Honeywell UOP, Imperium Renewables, Renewable Energy Group and Aquaflow Bionomic Corporation. The global aviation alternative fuel market is projected to grow at a CAGR of four per cent in the period 2017 to 2023. This figure is dismal, but the desperate situation as far as fossil fuel reserves are concerned, will probably accelerate the growth of bio-fuels in aviation. The fact that bio-fuels are the future of power generation in aviation, is certain; however, the time horizon over which it will outweigh fossil fuels, is indeterminate.