Written by Jonny Williamson
As an industry, global aviation contributes almost 650 million tonnes of carbon dioxide to the atmosphere every year, two percent of the total man-made CO2 emissions. If the aviation industry were a country, astoundingly it would be ranked as number 21 in terms of GDP, with an estimated global economic impact of US$425 billion. With a growth of five percent year on year, the industry has been under mounting governmental and public pressure to reconsider the long-term environmental impacts of its business.
(Figures from Air Transport Action Group, ATAG)
There has been mounting exposure on the use of so-called ‘second-generation bio-fuels’, with every corner of the globe seemingly investigating potential sources of bio-fuel supply. The first-generation of bio-fuels relied on crops such as corn and soy beans to produce ethanol, which diverted valuable farming space away from food crops, and lead to an excessive use of pesticides and water. The latest bio-fuels are being more responsibly sourced from algae, wood chips and weeds such as camelina sativa and pennycress. Camelina and pennycress are both high-oil relatives of mustard weeds, which can be refined like oil or fermented like beer to produce a low-energy alternative to jet fuel.
Last summer, Boeing flew their latest jumbo freighter, 747-8F, from Seattle to the Paris Air Show on a mix of 15 percent camelina and 85 percent traditional jet fuel. This was quickly followed by two flight tests by the US Navy with both the T-45 training aircraft and AV-8B Harrier successfully completing the flights on a 50/50 mix of camelina and jet fuel.
At the beginning of 2012 Etihad Airways flew a Boeing 777-300ER on a 14 hour test flight from Seattle to Abu Dhabi on a blend jet fuel and recycled cooking oil, and Hong Kong Cathay Pacific Airlines have recently announced plans to fund research to convert a jungle plant into bio-fuel.
There have been many more examples of airlines using new bio-fuel mixes during demonstration flights, but a great many less have made the leap to commercial flights. German airlines Lufthansa are one exception which operated the world’s only sustained flight from Hamburg to Frankfurt. Lasting six months and 1,200 flights, the trial managed to reduce regular CO2 emissions for the route by almost 1,400 tonnes.
It would appear that airlines from across the globe are investing in greener fuels. However some have suggested that rather than serious initiatives, these proposals and demonstration flights are mere PR exercises in the hopes of fostering a better public persona. There has been some call to refocus money and research into finding alternative fuels for the increasing amount of automobiles on our roads, which could prove a lot more cost-effective than trying to find sustainable alternatives to jet fuel.
Amid suggestions they should be focusing on reducing the amount of aircraft in the sky, the aviation industry has admitted that bio-fuels are still a very long way off from making a dent in the billions of litres airlines annually use. At the moment it would seem that bio-fuel remains too costly to be a practical solution and without a major step up in operations, will continue to be so. Yet the industry has made commitments to reduce its carbon emissions by 50 percent by 2050 and have carbon-neutral growth a lot sooner.
In 2010 aerospace firms Honeywell and Safran started a joint venture to invent and utilise electric motors in aeroplane wheels to taxi the craft around an airports runways, one of the most inefficient parts of any journey. The current use of the crafts jet engines creates a significant amount of CO2 emissions, not to mention the high volume of noise pollution and the lowering of airport operational efficiency.
Researchers at the University of Lincoln, England, have now taken this venture one step further, by suggesting that the combination of weight and speed when a plane lands creates the equivalent of 3 megawatts of energy. If captured, this energy could then be utilised to power Honeywell and Safran’s electric motors used during taxiing.
