Environmental Efficiency

Aviation’s global  environmental profile in 2010

Efficiency in everything we do

Sustainable growth calls for us to meet the needs of today without depleting the resources needed for future generations, or causing undue environmental degradation. The industry is conscious of aviation’s environmental impacts and its contribution to climate change. Efforts to minimise these have always played an important role in aircraft design and engine manufacturing. Furthermore, every aspect of current operations both in the air and on the ground is being examined to see how the industry can be made cleaner, quieter and more carbon-efficient.

Airline operations produced 649 million tonnes of carbon dioxide (CO₂) in 2010 (and 676 million tonnes in 2011), just under 2% of the total human carbon emissions of over 34 billion tonnes. Around 80% of all aviation emissions are from flights over 1,500 kilometres, for which there is no practical alternative transport mode. All industries, governments and individuals have an obligation to reduce their carbon output and with aviation, the incentive is two-fold.

With airlines spending $140 billion on fuel in 2010 (at 26% of an airline’s operating cost), the industry has a very good reason to reduce fuel consumption and has very aggressive programmes in place to do just that.

It was with confidence that the aviation industry collectively agreed in 2008 to the world’s first set of sector-specific climate change targets. The industry is already delivering on the first target — to continue to improve fleet fuel efficiency by 1.5% per year until 2020. From 2020, aviation will cap its net carbon emissions while continuing to grow to meet the needs of passengers and economies. By 2050, the industry has committed to reduce its net carbon footprint to 50% below what it was in 2005 (see graphic on right). 

These targets will be reached using a range of different efficiency opportunities and by working collaboratively with the support of governments.

Technology
Air travel has always relied on advances in efficiency. The very nature of flight dictates that aircraft must be as light as possible and fuel is heavy. Airline economics dictate that costs have to be reduced; and fuel is expensive. Since the beginning of the jet age, aircraft have reduced fuel use per passenger kilometre by well over 70% and these efforts continue. In fact, compared to those first jets, aircraft can now either carry two and a half times as many passengers or fly two and a half times further for the same aircraft takeoff weight. Of the billions of dollars spent each year on research by aircraft and engine manufacturers, more than 70% is used for measures that will improve fuel efficiency.

This research and technology includes new aircraft construction materials, aerodynamic components and new airframe designs. These efforts are most dramatically displayed in the step-change improvements made when new generations of aircraft enter service — typically each new aircraft is between 15% and 25% more fuel efficient than the model it replaces. Airframe manufacturers are currently at a peak of new aircraft model introductions, working with engine makers to deliver new ultra-efficient models such as the Boeing 787 Dreamliner, Bombardier CSeries, ATR 600, Embraer E-Jet and Airbus A380 and A350 XWB operating already, or due to enter service in the next few years. The two largest aircraft manufacturers also have model upgrades due to enter service, with Airbus’ A320 NEO and Boeing’s 747-8 and 737 MAX set to provide further step-changes in performance.

Operations
Those aircraft already in the fleet can also be made more efficient as new technologies and materials are developed. Adding ‘winglets’ to the tips of an aircraft’s wings has saved over three billion gallons of jet fuel so far, with the devices being retro-fitted to over 5,000 aircraft. They are also being developed for other aircraft currently flying.

Another area providing significant savings is weight reduction through new cabin configurations, lightweight seats and new equipment. By simply replacing catering trolleys on-board its European fleet with a lighter model,  Lufthansa estimates it will reduce carbon dioxide emissions by nearly 30,000 tonnes annually. United Airlines provided iPads to its pilots which contain all navigational charts and save 300,000 gallons of fuel by eliminating the weight of the old paper charts.

A number of airports and airlines are trialling the use of ‘green departures’, allowing pilots to take-off and climb to the optimal cruising altitude in one smooth, continuous ascent. This is in contrast to the traditional method of climbing to the cruising altitude in several steps. By using this new departure method at Copenhagen Airport, some 10,000 tonnes of fuel and 32,000 tonnes of carbon dioxide were saved in one year alone.

Satellite-based and on-board precision navigation systems allows air navigation providers to re-design airspace and procedures so that aircraft can fly optimal fuel-saving routes into and out of the busiest airports in the world. These new departure routes have reduced departure delays by more than 2.5 minutes per flight at Atlanta Hartsfield Airport since their introduction. Annual fuel savings are estimated at $34 million, with cumulative savings of $105 million from 2006 through 2008.

New fuel-saving procedures for approach routes into airports are being trialled, especially continuous descent operations (CDO), where an aircraft descends towards the airport from its cruising height in a gradual, continuous, approach with minimum thrust — rather than via the conventional series of stepped descents. Savings of up to 150,000 tonnes of fuel a year, or 500,000 tonnes of CO₂, could be made in Europe alone if CDO approaches were more widely adopted. The noise footprint of a CDO is also substantially smaller than conventional approach procedures.

Infrastructure
The next generation of air traffic management (ATM) network-enabled technologies are based on the Single European Sky ATM Research programme (SESAR) in Europe and the Next Generation Air Transportation System (NextGen) programme in the USA. They will improve efficiency by maturing and implementing ATM technologies and procedures.

The €2.1 billion investment in the Single European Sky could deliver a 12% reduction in environmental impact alone as it saves between 8 and 14 minutes of flight time, 300-500 kilogrammes of fuel, and 948 to 1,575 kilogrammes of CO₂ per flight. The USA’s Federal Aviation Administration (FAA) estimates that NextGen will reduce delays by 35-40% in 2018 compared with today’s systems. And every minute of delay saved also means a reduction in fuel use. SESAR and NextGen will enable air traffic control to evolve further, freeing the aircraft to fly at its most efficient profile possible while achieving new levels of safety in the air and on the ground.

By working together with airlines, airports and manufacturers, air navigation service providers are developing common procedures to ensure aircraft are flying the most efficient route through take-off, cruise and landing. As part of the SESAR programme, 18 aviation groups are working on the Atlantic interoperability Initiative to Reduce Emissions (AIRE) project. By the beginning of 2010, over 1,150 flights had been performed in the AIRE framework, saving over 400 tonnes of CO₂ as a result of new procedures.

Flexible routes can also be deployed, allowing pilots and airline operations teams to take advantage of the very latest weather and wind data to plot the most efficient flight path, sometimes altering course mid-flight to save even more fuel. The iFlex project led by the International Air Transport Association (IATA) reduced flight-time by up to 17 minutes when deployed on the Atlanta to Johannesburg route, saving up to seven tonnes of CO₂ per flight.

The challenge now is to take the results of these various projects and make them an everyday occurrence across the network.

These advances in environmental performance illustrate the concerted efforts the aviation industry is making to reduce its environmental impact in the skies. However, it is also important to recognise the progress made on the ground. Programmes such as Airports Council International's (ACI) Airport Carbon Accreditation have had enormous success in Europe, saving over a million tonnes of CO₂ in its first two years of operation. It currently extends to airports representing 52% of all European air traffic.

Energy-efficient terminal building design often takes advantage of sophisticated environmental control technology to regulate lighting, cooling and heating within the airport. Most new airports are built using LEED certification and a number of airports have installed on-site renewable energy sources such as wind turbines, photovoltaic panels and ground heat pumps. The solar panels at Athens International Airport have helped cut CO₂ emissions by 10,000 tonnes per year. As major transportation hubs, many airports also have significant intermodal transport exchanges. Heathrow Airport in London, for example, has extensive public transport links, with only 30% of passengers arriving by private cars. Many airports also encourage on-airport staff to either take public transport or have organised car pooling schemes.

Many airports now provide fixed electrical ground power units. These plug the aircraft directly into the mains power so they do not use fuel to run on-board systems such as air conditioning while sitting at the airport gate. At Zurich Airport alone, installing these units on 50 gates has resulted in 33,000 tonnes of CO₂ reduced annually. Furthermore, many airports are taking advantage of hybrid, natural gas or electric vehicles for use by ground crews on the tarmac.

Biofuels
The industry is also making significant progress to develop sustainable biofuels for aviation. From a virtual dream in 2007 to regulatory approval being granted for passenger flights in 2011, the development of aviation biofuels has shown remarkable progress in recent years. Over 1,500 passenger flights have taken place so far and the consensus is that the lifecycle carbon saving from moving to biofuels could be up to 80% over that of traditional jet fuel.

The types of feedstock being investigated for aviation biofuels include non-food crops that can be grown in areas which do not impact food crops or water use: innovative use of by-products such as household waste, excess gases from industrial processes and the waste from agriculture and forestry, and micro-algae. The aviation industry took careful note of the negative impacts that occurred when the first generation of biofuels was deployed in road transport and is determined not to repeat those mistakes.

The major challenge now remains the production of large quantities of sustainably produced biofuel at a commercially competitive cost to airlines. Current prices indicate biofuel costs are around three times as much as conventional jet fuel. This is expected to fall as production capacity is increased beyond the current small-scale projects.

Noise
Modern jet aircraft are 75% quieter than the first models and each new generation continues this downward trend. While each new model has reduced its noise footprint significantly, the number of aircraft movements has grown and the sensitivity of people living under flight paths has also increased. However, according to the FAA, the number of people negatively impacted by aircraft noise in the United States decreased from seven million in 1975 to fewer than 300,000 in 2009, despite the more than doubling of flights during that time. This trend is being replicated around the world: not only do aircraft get quieter, but airports and air traffic controllers work to provide operational noise mitigation measures and local governments work with the aviation industry to more appropriately zone areas around airports.

End-of-life
An aircraft will typically remain in service for around 20-25 years. During that time, it will fly on average 40,274,144 kilometres — over 1,000 times around the world — with some long-haul aircraft flying over 100 million kilometres, for several airlines. Once it reaches the end of its useful life, an aircraft can be recycled not only to ensure proper disposal but also to take advantage of the many high-quality components and materials of which they are made. Organisations such as the Aircraft Fleet Recycling Association are working with the manufacturers of aircraft and engines, component suppliers and operators to establish best practice guidelines for the disposal and recycling of aircraft. Manufacturers are also ensuring that new aircraft are designed not only for a long, safe and efficient life, but also for the end-of-life opportunities. The Airbus PAMELA project demonstrated that more than 70% of the airframe can be recycled, up to 85% can be sold for re-use or recycling and scrap metal can be reduced by 3-15%.

New materials such as carbon fibre present new challenges for aircraft designers to find ways of dealing with the materials once the product leaves service. Processes are being developed to allow these new materials to be recovered and potentially recycled once the aircraft reaches the end of its useful life. Major aircraft manufacturers are also ensuring that manufacturing facilities meet (and often exceed) global reporting requirements on environmental standards, with most major manufacturing sites certified to ISO 140001 standards.