Defence and commercial aviation need to work together to transition from fossil fuels
16 Mar 2022|

ASPI’s The geopolitics of climate and security in the Indo-Pacific is a sobering read that describes the international security implications of climate change in our region in 2035. In one description of a plausible future, the authors assume that the global energy system will undergo rapid transformation from fossil fuels to renewables. While there is active debate on how this should occur for areas such as the energy grid and various parts of the transport sector, aviation doesn’t appear to have attracted nearly as much discussion.

However, the aviation sector should heed ASPI’s warning because as both a military and a commercial venture, sustainability in aviation has been a constant challenge since the jet engine was invented.

The commercial aviation sector and Defence aviation need to collaborate to grow an alternative fuels market in Australia to supplement fossil fuel supplies and set up their long-term transition to full renewables. Otherwise, non-viability and irrelevance will occur ‘gradually and then suddenly’.

Since the first flight of a turbojet-powered aircraft in 1939, the recurring cycle of engine evolution followed better fuel performance has created deep-rooted conservatism and dependence on fossil fuels by aircraft and engine manufacturers.

The fuel crisis of the 1970s raised questions about the validity of this dependence on oil supplies while adding volatility in the cost of fuel to the mix. Between 1972 and 1985 the price of a barrel of oil per fluctuated from under $20 to reach a peak of over $120 only to drop below $20 again. To counter concerns about energy security and fuel-price volatility, countries such as the US supplemented their conventional jet fuel reserves with fuels produced from coal, tar sands and shale oil.

Large military operators also transitioned in response to the same concerns. In 1979, the US Air Force moved from its main operating fuel jet propellant number 4 (JP4), which is a blend of kerosene and gasoline, to JP8, a commercial aviation fuel containing military additives for protection against corrosion, static build-up and icing.

More recently, challenges associated with greenhouse effects due to fossil fuel use have been in focus. Based on trends prior to Covid-19, commercial aviation’s contribution to global emissions was estimated to be 2–3%. That figure is misleading, however, because the emissions footprint is more severe due to the fuel’s emissions release at altitude. Before Covid, the aviation industry’s emissions were increasing, with overall fuel consumption expected to grow by 38% between 2008 and 2025.

In the face of these challenges, the aviation sector has sought to use ‘drop-in’ alternative fuels that are suitable for existing aircraft. Investment in drop-in alternative jet fuels is mainly due to the time and cost involved in engine and aircraft design and development. These fuels are interchangeable with conventional fuels with no degradation in performance or safety and don’t require any engine or airframe modifications.

Drop-in alternative fuels are divided into two broad categories. The first includes synthetic jet fuels produced from coal, natural gas and other hydrocarbons. The second includes bio-jet fuels produced from biological matter such as plant oils and animal fats. Synthetic jet fuels can be produced through gasification of organic matter, the results of which are further synthesised through the Fischer–Tropsch process. Bio-jet fuels are produced through hydroprocessing (removing chemically bound oxygen from the initial product to bring it to the desired jet-fuel boiling range) of biological matter.

Synthetic jet and bio-jet fuels burn much cleaner than their traditional counterparts, leading to lower greenhouse-gas emissions. Some synthetic jet-fuel production methods are emissions-intensive, however, reducing their overall benefits. In contrast, the entire emissions lifecycle of bio-jet fuels from production to consumption is much better than both conventional and synthetic fuels, making them attractive from an emissions and sustainability perspective. For instance, bio-jet fuel produced from camelina reportedly delivered a 70% savings in lifecycle emissions compared to conventional fuel.

The establishment of industrial-scale alternative fuel production facilities has traditionally been deemed uncompetitive and hasn’t been widely pursued. A 2013 study by Qantas and the Australian Renewable Energy Agency estimated that a reference facility capable of producing 20,000 barrels a day of sustainable aviation fuel from natural oils would cost approximately $1 billion.

Accordingly, there has been a clear absence of subsidies and seed investment for such ventures in Australia. Over the past few of years this situation was exacerbated by a glut of fossil fuels that saw the price of oil drop to record lows. The aviation sector has continued to rely on fossil fuels with the knowledge that it is still at the whim of oil cartels and constantly exposed to external shocks. The Ukraine crisis once again highlights the effects of external events on the cost of oil.

Factors such as technological maturity and cheaper renewables have started to accelerate the transition of large portions of the market towards renewable fuels such as hydrogen. A 2020 study conducted by CSIRO and Boeing suggests that, due to their energy per volume, sustainable aviation  fuels produced from hydrogen will be the fuel of choice for medium- to long-haul flights out to 2050.

With new technologies coming online, the aviation industry—including Defence—will need to revisit its investment strategies if it wants to gain access to sustainable aviation fuels. But this can’t be achieved by single players operating in silos. Choosing to take the traditional approach and leaving it to the market to look after itself to save fuel costs in the short term will likely have long-term consequences like supply shortages or paying high premium when the rest of the transport sector has completed the transition to renewables. These factors should be as troubling for Defence as they are for the commercial aviation sector.

The commercial sector and Defence should form a coalition to shape the aviation fuel market in Australia by providing a secure source of investment for alternative fuel producers. The alternative fuels can then supplement traditional fuel sources until a complete transition away from fossil fuels can occur. The CSIRO–Boeing study suggests that one plausible future includes the production of electrofuels, which use electricity from renewable sources and combine them with green hydrogen and CO2 to produce sustainable aviation fuels at the point of delivery. However, without the appropriate investment and support such a future in 2050 is just as much a mirage as energy security, stable fuel costs and low emissions have been since 1939.