Plant power

environmental cost. Aircraft emit a variety of byproducts into the upper atmosphere, including carbon dioxide (CO2), water vapour, nitric oxide, nitrogen dioxides, sulphur oxides and soot. Each varies in how long they may remain in the atmosphere and in the way in which they interact.

A report by the United Nations Intergovernmental Panel on Climate Change (IPCC) relates that aviation represents 2 per cent of global emissions and it is a figure that is forecast to grow as passenger numbers continue to increase. Not surprisingly, airlines, manufacturers and governing bodies alike are taking the responsible stance to seek out ways in which to reduce aviation’s environmental footprint. Rob Wood, General Manager, Group Sustainability at Virgin Australia States that, “…sustainable aviation fuels can reduce emissions on a lifecycle basis by up to 50-80 per cent”. “Lifecycle” giving consideration to all inputs (raw materials and energy) and outputs (products, waste materials, and environmental impacting components such as CO2) in the process. 

Ultimately, the International Air Transport Association (IATA) has set ambitious goals in relation to emissions. They are seeking an average improvement in fuel efficiency of 1.5% each year from 2009 to 2020, setting a cap on net aviation CO2 emissions from 2020 (carbon-neutral growth) and halving net aviation CO2 emissions of by 2050, relative to the levels of 2005. Many diverse alternatives are being pursued to achieve these goals.

Improved route management, enhanced engine technology, the incorporation of advanced materials and alternative fuel sources are just some of the ways being investigated to enhance the efficiency of the modern airliner.

Boeing has dedicated 737, 757, E170 and 787 aircraft, to their EcoDemonstrator program in recent years. To date, more than 50 new technologies have been tested across their four flying test-beds and in 2018 more than 30 new technologies will be tested on board a 777 freighter in conjunction with FedEx. Notably, most of these flights will be conducted using 100 per cent biofuel, a first for a commercial aircraft and a significant step towards emissions reduction. It is yet another indicator that the use of biofuels in aviation is much closer than we may be aware.

‘Biofuels in aviation may be much closer than we think.’

Biofuels History.

When most of us think of biofuels, we consider the E10 blended motor fuel that we pump into our cars at the bowser. E10 utilises a combination of 90 per cent traditional gasoline and 10 per cent ethanol and is promoted as a ‘green’ fuel option.

Ethanol, as used in E10, is a form of alcohol produced from a fermentation process using the glucose derived from sugars, starch or cellulose. These are generally produced from the waste of feedstock ranging from sugar cane and sorghum to various woods and grasses. 

When looking towards the the use of biofuels in aviation there are additional considerations, including the temperature range in which an aircraft and its fuel system and engines operate. Aviation fuels are required to have a low freezing point and, at the other end of the scale, a high burning or ‘smoke’ point. Also, careful consideration must be given to any effect on hoses and seals, any tendency for a biofuel to oxidise at low temperatures and gel and ridding the fuel of any funghi or bacteria that may be associated with the feedstock. 

As a consequence, potential biofuels are rigorously tested prior to certification to ensure their performance on all fronts and are ”…chemically equivalent to, and meets the same technical, performance and safety standards as conventional jet fuels,” a QANTAS spokesperson stated, while Virgin Australia’s, Rob Wood, further adds that, “…as these fuels are used more regularly, many are demonstrated to have improved outcomes in terms of fuel efficiency as well as benefits in how cleanly the fuels burn and lower freezing points”.

‘Potential biofuels are rigorously tested prior to certification.’

The move towards biofuels has not taken place overnight. The first biofuel flight a decade ago was made using waste vegetable oils and a small Aero L-29 Delfin single-engined jet aircraft. The Delfin undertook a United States trans-continental flight from Nevada to Florida, using 100 percent biofuel for the majority of the sectors on its 2,500 mile flight. Also in 2008, a Virgin Atlantic Boeing 747 undertook the first commercial flight between London and Amsterdam with one engine fed with a 20 per cent blend of biofuel.

Since those first flights, a range of flights have taken place in aircraft ranging from general aviation types to helicopters and even military fast jets. In doing so, a variety of feedstocks has been employed. From the plant world, Jatropha, Camelina and Brassica Carinta, while there have also been forms of algae, tallows (fat) and waste vegetable oils used.

With the potential to have a true global impact, Australia is also at the forefront in the emerging field of biofuels.

An Australian Perspective.

Australia’s aviation heritage is rich in history. The pioneer aviators once sought to conquer the tyranny of distance, however in the 21st century, those air routes are well established and the challenge now lies in the pursuit of efficiency and the minimisation of the environmental impact.

Australia’s first commercial biofuel trials took place in 2012, when a QANTAS Airbus A330 flew a return service to Adelaide from Sydney and a Jetstar Airbus A320 operated between Melbourne and Hobart. Both aircraft were powered by a biofuel 50/50 blend of conventional jet fuel and used cooking oil, certified for use in aviation. 

On a much smaller scale, in 2017, a two-seat Vans RV-9 set course from Wollongong NSW for Tyabb in Victoria under the banner of the “On Wings of Waste”. Flown by Jeremy Rowsell and powered by a single WAM120, three cylinder turbo Diesel engine, the 120Hp powerplant used conventional fuel, blended with 10 per cent fuel manufactured from plastic waste.

Jeremy Rowsell highlighted that the manufacturer’s process, produced the diesel fuel for around 32 cents per litre. By calculating the costs of waste management, landfill and the costs of producing new fossil fuels and comparing these to the costs of utilising a widely available waste product, it quickly becomes self-evident that there is economic merit in the concept for light aircraft also.

Virgin Australia is looking to a future trial based out of Brisbane and Rob Wood comments that the fuel will follow an, “..Alcohol to Jet pathway, converting isobutanol to jet fuel,” with the feedstock from the isobutanol being derived from non-edible corn. Rob adds that there are also other feedstocks that, “…show real promise in their potential to support the development of this industry in our region”.

As certified aviation biofuels are chemically identical to their fossil fuel predecessors, they are commonly known as “drop-in” fuels as they do not require any modifications to aircraft equipment, nozzles, or placarding and are handled in the same way as conventional jet fuels.

In terms of the infrastructure required to support biofuels, Virgin Australia foresees some minor investments to ensure the “requisite blending facilities” are available and that the major challenge lies in the, “…capital and infrastructure required to produce these fuels at a commercial scale.”

A QANTAS spokesperson cites that the airline’s “…long term goal is for Australia to have its own refinery that is equipped to process biofuel feedstocks, such as Carinta”. The feedstock, Brassica Carinta, is an industrial-type, non-food mustard seed and was used on QANTAS’s most recent biofuel flight on January 28th of this year. As QF96, a Boeing 787-9 flew the 15-hour sector between Los Angeles and Melbourne using a 10 per cent biofuel blend that saw a 7 per cent reduction in emissions on the route when compared to normal operations.

QANTAS explains that the biofuel for the flight was developed by Canadian-based, Agrisoma Biosciences in a partnership that will see both companies working with Australian farmers to grow the country’s first commercial aviation biofuel seed crop by 2020.

The Future of Fuel.

2020 looms on the horizon as a landmark year for biofuels in various ways. As stated previously, it is the year that IATA has named to set a cap on net aviation CO2 emissions meaning carbon-neutral growth.

Closer to home, it is also the year that QANTAS plans to have its Los Angeles-based Airbus A380s and Boeing 787-9s powered by biofuel supplied by US-based energy company, SG Preston.

2020 is really only just around the corner, but the journey of biofuels has a significant future yet to run. Its continued development, trials and refinement shall see biofuels and their feedstocks to continue advance in a commercial sense as at this time their production is still at a higher cost than their fossil counterparts.

Still, for many, the real savings are not to be found solely on a balance sheet, but they lie in lessening the impact of air transport on the environment. The growth of biofuels in aviation is no longer merely an option, it is a doorway to long term sustainable and responsible growth.