Reducing Aviation’s Environmental Impacts One Kilo at a Time
A lot has changed since civil aviation first took off in 1911. For one thing aeroplane weight has increased from around 360kg (Sommer Biplane) to 276,000kg (Airbus 380). Similarly, from just a single passenger global passenger numbers are now forecast to reach 2.57 billion this year. Despite all these changes some things remain. Kerosene is still the favoured fuel and today with a price of $113 per barrel ($40 in 2002), fuel is not only driving the environmental debates the aviation industry faces, it is also profoundly shaping the planes we fly in.
Public debates about aircraft environmental impacts have typically focussed on cutting environmental impacts at the user stage, for example by flying less and offsetting carbon. Behind the scenes, a less well-aired approach to reducing environmental impacts starts with the planes themselves. Even from an historic perspective, aircraft manufacturers have been slowly making air travel more efficient. Looking at the main production models of the largest western airliner manufacturers over the past fifty years we can see significant savings in terms of kilo per passenger kilometre. This is consistently down from over 0.07 kg/person-kilometre in 1960, to less than half (43%) today.
One way efficiency has been delivered is reducing the mass of the planes, or light-weighting. Examples of this approach include reducing the weight of a seat or by using new technologies, and in particular, innovative materials that provide the same properties as currently but for less mass. A summary of some of these approaches in use today and in the near future is below.
But what comes next? Set up in 2001, the Advisory Council for Aeronautical Research in Europe (ACARE) has set targets for European aircraft manufacturers to reduce fuel consumption and CO2 emissions by 50% for new aircraft produced in 2020 compared to a similar one produced in 2000. These gains are expected to come from improved engines, airframes and air traffic management. More efficient aircraft are expected to bring 20-25% of this improvement. Closely aligned to delivering the ‘2020 Vision’ is the Clean Sky initiative, a public-private partnership between the European Commission and the aeronautical industry.
Clean Sky’s 1.6 Bn Euro budget focuses on multi-disciplinary approaches to bringing advanced aircraft technologies together from design stages to testing and interaction in the real world. Work is organised into six strands.
· SMART Fixed Wing Aircraft is developing new wing technologies and new aircraft configurations that reduce weight, drag, and noise as well as allowing for new engine mountings.
· The Green Regional Aircraft theme is reconsidering smaller commercial aircraft from all perspectives. Work streams include all electric options, trajectory management, as well as lower-weight and noise configurations.
· Demand for Green Rotorcraft is expected to grow significantly. Innovative rotor blades and engine installation for noise reduction, lower airframe drag are major development areas.
· Sustainable and Green Engines is designing and building five engine demonstrators to integrate technologies for low noise and light-weight low pressure systems, high efficiency and low NOx. A particular focus is the new engine designs (open-rotor and geared-fan engines) that offer opportunities for a step change reductions in CO2 emissions.
· The Systems for Green Operations theme balances development in internal aircraft systems such as thermal and electrical systems with green trajectories, mission and SMART ground operations.
· Rethinking the linkages between aircraft design, production, operation and end of life to optimise the use of raw materials and energy is behind the Eco-Design strand. Concepts such as improved disassembly, whole life management, improved materials and compliance with the EU REACH Directive on chemical components are being systematically applied to reducing aircraft environmental impact.
With current aircraft production cycles already extending beyond 2020, the EU has extended ACURE’s mission to 2050 under the name ‘Flightpath’. Its goal is to reduce CO2 emissions by 75% per passenger kilometre by 2050. Given a background of 26,000 flights a day in Europe, even 75% cuts won’t be enough to offset the mounting environmental impact if the current 4.5% annual passenger growth rate continues to 2050. Where next? Well perhaps better trajectories, engines and a switch from kerosene can help bridge the gap.











