New vistas in aviation

The aviation industry is one of the world’s top users of oil, consuming around 1.5 billion barrels of A-1 jet fuel (a modified form of kerosene) annually, not counting diesel and petrol usage by ground vehicles at airports and also the thousands of military aircraft in service.

Nearly 1,400 civil airlines operate a fleet of 26,000 aircraft serving nearly 3,900 airports through a route network of several million kms. More planes are being ordered and added practically every day as passenger numbers soar. Cheaper fuel has benefitted the industry and passengers, as airlines can offer deep discounts without necessarily affecting their bottom line.

But the increase in fuel usage brings its own share of problems, especially from an environmental perspective. Today’s jets are much more fuel efficient than the jets used in the 1960s but their impact on the environment remain a concern.

Worldwide, flights produced 705 million tonnes of CO2 in 2013. Globally, other human activities produced over 36 billion tonnes of CO2. Aviation is the most carbon-intensive transport mode, responsible for about 5% of man-made climate change. If aviation were a country it would be ranked 7th in the world for CO2 emissions - between Germany and Korea. But the industry is keen to ensure that by 2050, net aviation carbon emissions would be half of what they were in 2005.

Target

In order for the aviation industry to reach its target of 1.5% average fleet fuel efficiency improvement per annum from 2010 until 2020, the world’s airlines will have to purchase 12,000 new aircraft at a cost of $1.3 trillion. But there is a catch - since new aircraft have a lifespan of 20-30 years, they could lock in unnecessary fossil fuel consumption for decades to come, greatly undermining global efforts to de-carbonise.

This is why the airline industry has to look for other avenues for fuel with the future in mind, despite the abundance of cheap oil for the moment. Increasing jet fuel efficiency is one option, but one can only do so much.

The new Airbus A380, Boeing 787, ATR-600 and Bombardier CSeries aircraft already use less than three litres of jet fuel per 100 passenger kilometres. This matches the efficiency of most modern compact cars. But to go beyond these figures, the airlines will have to rely on alternative fuels, particularly sustainable biofuels.

They have already been identified as excellent candidates for helping achieve the above industry targets. Biofuels derived from biomass such as algae, jatropha and camelina have been shown to reduce the carbon footprint of aviation fuel by up to 80% over their full life-cycle. If commercial aviation were to get just 6% of its fuel supply from biofuel by 2020, this would reduce its overall carbon footprint by more than 5% and if other fuels are introduced, the savings will be greater.

Trial

It is in this context that the Budget airline EasyJet is set to trial new ‘hybrid’ planes using hydrogen cells that it hopes could cut its fuel bill by up to US$ 35 m (or in terms of quantity, around 50,000 tons of fuel) a year. The new technology would mean its planes could taxi to runways without using jet engines. This is great news, since airliners use around 5 percent of the total fuel consumption for taxiing at airports.

There are other benefits too. Passengers could be served water created as a waste product from hydrogen batteries used in the fuel system. They could also be used for sanitation purposes. Ian Davies, head of engineering at the airline who described the water as ‘potentially the freshest, cleanest water,’ says the industry could cut costs further with the new technology.

EasyJet’s new technology, which involves a fuel cell capturing energy from the aircraft’s brakes when it lands, would also help reduce carbon dioxide emissions. The airline hopes to begin ground-based trials of the hybrid plane later this year.

Emissions

But this is not the only such effort underway in the aviation community. Operational measures like better management of airplane traffic, both at airports and in the air, have further reduced emissions. Many improvements involve changes to existing planes like adding winglets to wings, which reduce drag and improve efficiency by a few percentage points.

A six-year NASA mission to advance green aviation has found that if airlines embrace certain technologies to reduce fuel burn, noise and air pollution, they could save over US$ 250 billion over 25 years. The researchers examined technologies to refine or revamp aircraft design from top to bottom: from the materials they are made of and what fuels aircraft, to tail, wings and engines.

Such improvements would make airplanes lighter, faster, quieter, cleaner and more fuel-efficient. For example, Boeing’s ecoDemonstrator 757 flying laboratory confirmed that an aircraft could fly safely with smaller vertical tails, reducing weight and drag. Future planes could have lighter wings that can quickly change shape to better handle the stresses brought on by turbulent air.

A futuristic hybrid wing body concept - in which a jet’s wings join the fuselage in a smooth, seamless line and the engines are mounted on top - has undergone wind tunnel tests.

Recently, the Oslo Airport in Norway became the first airport in the world to supply Bio jetfuel via its regular fuel hydrant system. The biofuel, which is produced from camelina oil, is available for airlines to buy at Oslo and is supplied from the main fuel farm, via common storage and distribution facilities. Planes could eventually be converted to run on biofuels alone, which will pave the way for more environmentally friendly skies. They could also be powered by electric or fuel cell batteries.

Changed

Let’s face it, the basic shape of planes has hardly changed in the last 50 years - a plane is still a metal tube with wings. However, manufacturers are working on radical new ‘clean sheet’ designs which may fundamentally alter this familiar shape to achieve greater fuel efficiency and aerodynamics. For example, there are designs which call for the cockpit to be in a hold-like area with live feeds of the outside on video screens, which will do away with the conventional cockpit altogether.

There are calls for the windows to be replaced with video walls and Airbus has already filed for a US Patent for a new smart aircraft with interactive glass so passengers can learn about the sights they see below. Thus, planes may look radically different in say, 100 years from now. They will also be faster (supersonic or better) in the future - a London to Sydney run in just two hours may not be a far-off dream. All these technologies could make air travel even more safer, more affordable and more environmentally friendly.