When can we expect to see a low-carbon flying future? What will the aircraft of the future look like?
Aviation and carbon emissions
The global aviation industry produces around 2% of all human-induced carbon dioxide (CO2) emissions. In the transport sector, aviation produces 12% of CO2 emissions, while 74% are produced by road transport. Although aircraft have improved fuel efficiency greatly – today’s jet aircraft are over 80% more fuel efficient than those used in the 1960s – there is clearly still more to do.
Last year saw a landmark deal between 191 nations to limit carbon emissions from aviation. The Montreal United Nations accord applies to passenger and cargo flights that generate more than 10,000 tonnes of greenhouse gases annually. Carbon emissions will not be capped, but airlines will pay around 2% of the industry’s annual revenue to fund forestry and carbon-reducing initiatives to offset the sector’s environmental impact.
Some regions have committed to ambitious cuts in aviation emissions, such as the European Union, where the Flightpath 2050 Vision for Aviation requires a 75% cut in CO2 emissions, 90% cut in NOx emissions and a 65% reduction in noise pollution generated by aircraft.
The slow pace of change in aviation
Although aviation contributes a small-sounding 2% of global carbon emissions at present, that figure could climb higher as other industries improve efficiency and cut their emissions, making aviation’s contribution proportionately larger; experts project that aviation emissions will quadruple by 2050, representing up to 22% of global emissions.
However, aviation also operates at a slower pace due to safety concerns, the nature of aircraft usage and procurement, meaning the industry tends to be slightly more risk averse in new developments than their automative counterparts. With this emphasis on safety, the industry even with the imperative to improve performance, could still be decades away from innovations involving electric engines start to make a real impact.
There was a time when biofuels were heralded as the solution to the aviation industry’s emissions problem. Around 2,500 successful flights have taken place with this fuel to date, which is more efficient and low-carbon than the usual petroleum-based aviation fuel. While some airlines continue to investigate the potential of biofuels, they cannot alone hope to address the substantial problem of an industry that uses 300bn liters of jet fuel each year. While biofuels may form part of the solution, they are unlikely to be a panacea for overall problem.
The new generation of electric aircraft
Despite the long lead in time for aircraft development, there are some hugely exciting projects out there. Some interesting partnerships have been formed to create new solutions: Rolls Royce is working with Airbus and Siemens on hybrid electric-powered aircraft; UK-based Easyjet is pairing up with US-based Wright Electric to develop battery-propelled aircraft for flights under two hours; while Boeing recently purchased Aurora Flight Sciences, a developer and manufacturer of advanced aerospace platforms and autonomous systems.
These aircraft innovators are all seeking to find ways to use electric or hybrid systems to revolutionize flight. Initially, planes are expected to be small; two or six-seat aircraft to test the underlying principles. By the 2030s we could be seeing the first single-aisle commercial regional passenger jets.
Battery design is the key to unlocking the potential of the electric or hybrid aircraft. While aviation fuel offers 40MJ/kg, batteries currently offer only 1MJ/kg. In order for a plane to achieve the endurance and reliability required, battery technology will need to improve considerably.
The Zunum Aero: a glimpse of the future?
The Zunum Aero is an exciting initiative in partnership with Boeing, jetBlue and the Department of Commerce Clean Energy Fund. The organization is developing range-optimized hybrid-to-electric aircraft which will travel over 700 miles by the early 2020s, reaching to 1,000 miles by 2030. The vision is for a network that will feed into the today’s concentrated airport network by improving access to airport hubs.
The goals of Zunum are impressive. The aim is to create aircraft that will reduce air fares by 40-80%. Noise will be reduced by 75%, emissions by 80% and the company claims that by the 2030s it will be able to eliminate 40% of all commercial aviation emissions. The aircraft designs feature wing-integrated battery packs, hybrid-to-electric powertrains and quiet electric propulsors.
As these developments continue, aviation is set to become sleeker, cleaner and greener. The low-carbon flying future is on its way.