Reducing air pollution is on the global agenda. The Netherlands and Norway have boldly decided that new cars sold in their respective countries will be totally emission-free by 2025. Car emissions are responsible for over 50% of air pollution in urban areas, and an estimated 75% percent of global carbon monoxide emissions come from automobiles. Hybrids, fully-electric vehicles andhydrogen cars are slowly but surely easing their way into modern society, showing that this global issue is under consideration.
Regular old-fashioned cars burn fossil fuels, petrol or diesel, and produce toxic emissions. Not as toxic, though, as kerosene (jet fuel). The number of plane journeys is on the rise – in 2016, there is more than 100,000 flights around the world per day. Modern commercial aeroplanes have three limitations: they are inefficient, they are big, and they run on toxic fuels. A fully laden A380, according to its’ engine maker Rolls Royce, uses as much energy as 3,500 family cars – the equivalent to six cars for each passenger on board.
Aeroplane exhaust, like car exhaust, contains a variety of air pollutants, including sulphur dioxide and nitrogen oxides. It is estimated that there are 10,000 deaths per year from aeroplane emissions – more than die in air crashes. The most common causes of death due to air pollution are cardiovascular and respiratory diseases, including lung cancer, according to the World Health Organisation.
Aircraft emissions of nitrogen oxides, which are linked to lung damage have doubled since 1990 and are forecast to rise 43% by 2035. The combined effect of all of the pollutants associated with air travel multiplies the global warming impact and means that aviation is currently responsible for an estimated 5% of global climate pollution – and this figure could grow.
It is worryingly obvious that the air travel industry in its current form is grossly unsustainable. Fossil fuels are running out, and the level of worldwide pollution is reaching startling levels. The air travel industry is a multi-billion dollar industry, and it is the responsibility of the big players to instigate change.
In 2009, the International Air Transport Association (IATA) set the target to halve emissions by 2050, to improve fuel efficiency by an average of 1.5% per year to 2020; and to stabilise carbon emissions from 2020 with carbon-neutral growth. Since then, there have been four interesting avenues which have been explored by manufacturers.
The Future
Tesla CEO Elon Musk stated in February that he wants to build electric planes, which take-off and land vertically for added coolness. His car company are trailblazers when it comes to electric cars, and all car manufacturers are starting to think electric. However, Musk is the CEO of two companies, so his electric plane vision seems quite a distant one.
Airbus, on the other hand, has already made exciting moves towards an electric future. In 2014, their E-Fan 2.0 made its first public flight at the Berlin air show, capable of flying for half an hour and reaching speeds of 110 mph. In 2015, they successfully flew an electric plane across the English Channel. Since then, they have teamed up with German giant Siemens to push their project to the next stage.
An artistic impression of Airbus’ next phase, the E-Fan 4.0
Airbus is planning to fly regional planes capable of seating over 100 people with hybrid engines by 2030.
However, similarly to the innovations in the motoring industry, it is not just electric planes that are being conceptualized. EasyJet have announced that they will be trialling the world’s first hydrogen plane. The only emission associated with hydrogen power is water, which EasyJet claim will be so pure and clean that it could be drank.
These aeroplanes will be hybrids, using hydrogen energy to manoeuvre on the ground. EasyJet estimate that they use 4% of their fuel just taxiing on runways. If all of their planes use the new hybrid system instead of their jet engines to move around an airport, the low-cost carrier would cut their fuel bill by between $25m and $35m, depending on the oil price, the airline calculated.
According to EasyJet, if implemented across its fleet, the hybrid systems could save the airline from using approximately 50,000 tonnes of fuel a year.
It is unlikely that we will see a fully-powered hydrogen aircraft anytime soon though, due to a plethora of limitations associated with the fuel – including cost, fuel tank size and explosiveness.
A third and even more eco-friendly solution is solar power. Since planes fly above the clouds, they are directly exposed to sunlight.
In 2009, the Solar Impulse 1 was presented to the world – the world’s first solar plane. It flew 350 metres on the 26th June.
Two years later, the Solar Impulse embarked on its first international flight, taking 13 hours to fly from Switzerland to Brussels (it flew at 30mph).
In 2015, the Solar Impulse set-off on its most remarkable journey to date – embarking on a round-world journey. The plane flew eight stages from Abu Dhabi to Kalaeloa, including a remarkable four-day, 21-hour leg over the western Pacific – the longest solo flight in aviation history in terms of the time it took.
But it was damage to its batteries on that stage that forced Solar Impulse to then lay up for 10 months, for repairs and to wait for optimum daylight length in the northern hemisphere to return.
On 29th July, the Solar Impulse completed its round-the- world journey, when it arrived back in Abu Dhabi. It had completed 17 legs across Asia, the Pacific, America, the Atlantic, the Mediterranean and then finally the Middle East.
The aircraft has a large wingspan, in order to fit its 17,000 photovoltaic cells. It weighs a fraction of a Boeing 747 airliner – at a mere 2.3 tonnes.
“This is not only a first in the history of aviation; it’s before all a first in the history of energy. I’m sure that within 10 years we’ll see electric aeroplanes transporting 50 passengers on short to medium haul flights,” said Pilot Bertrand Piccard upon completing the flight.
Despite the completion of this remarkable journey there are obvious limitations – the plane is very slow, can currently only hold minimal weight, and needs a very large wingspan. Perhaps the future could see this technology integrated with fossil fuels, rather than flying the plane alone.
The fourth and arguably most feasible solution for a sustainable future of aircraft is biofuel. Biofuels are sourced from natural biological matter – such as plants or agricultural processes. These biofuels can be mixed with Kerosene, in order to dilute it and reduce emissions.
In 2007, Greenflight International made the very first flight of an aircraft powered entirely by 100% biofuel – it was waste vegetable oil in this case. The plane was made by the pilot that flew it. In November 2008 the same aircraft and flight crew flew from Reno, NV to Leesburg, FL using 100% biofuel for the first seven of the nine legs, the remaining three were completed on a 50% biofuel 50% JetA blend.
Since then, numerous airlines have flown demonstration planes powered by various biofuels. Virgin flew a coconut powered Boeing 747 from London to Amsterdam in 2008; Japan Airlines conducted a one and a half hour flight with a mixture of kerosene and algae biofuel in 2009.
In 2011, KLM flew the world’s first commercial biofuel flight, carrying 171 passengers from Amsterdam to Paris in a plane powered by used cooking oil. Since then, there have been over 20 international airlines following suit, with more than 1600 passenger flights having flown.
Boeing are frontrunners in bio jet fuel research and development. They are working with multiple key partners to improve existing biofuel capabilities.
Despite being cheaper than gasoline, more renewable and associated with lower carbon emissions, they have a lower energy output than traditional fuels and therefore require greater quantities to be consumed in order to produce the same energy level. There is also the concern that valuable cropland to grow fuel crops could have an impact on the cost of food and could possibly lead to food shortages, as well as the colossal quantities of water required for proper irrigation of biofuel crops would put a strain on regional water resources.
The aviation industry is foreseeing an exciting decade in alternate energy air-travel. The future of the aeroplane will certainly be a cleaner one, no matter which fuel-source wins the innovation battle.
0 comments:
Post a Comment