When Frank Whittle invented the jet-fuel engine in 1937, little could he imagine that nearly a century later aviation would be on the cusp of another revolution.
Around 7.8 billion passengers are forecast to fly globally each year by 2036, double the 2017 levels, according to industry body International Air Transport Association (Iata).
Such phenomenal air traffic growth means heavily polluted skies and an escalating fuel bill. This is unsustainable for governments and airlines, underscoring the need for greener solutions.
Many believe the future of aviation will be electric. After years of using jet fuel to power aircraft, the advent of electric planes may hold the promise of cheaper and cleaner flights.
“Powering aircraft through electric energy, or hybrid as a halfway measure, is a compelling concept,” says Ron Van Manen, head of programmes at Clean Sky 2, a European Union-led environmental research initiative. “Like with [electric] cars, this could bring carbon dioxide emissions to nearly zero.”
Air transport accounts for 2 per cent of total greenhouse gas emissions and this is projected to rise to 10 per cent by 2050, according to the International Civil Aviation Organisation (Icao), which makes addressing the environmental impact all the more pressing.
Iata wants a 50 per cent reduction in net aviation carbon emissions by 2050 (from 2005 levels), carbon-neutral growth by 2020 to help achieve that, and an average improvement in airlines’ fuel efficiency of 1.5 per cent from 2009 to 2020.
Abu Dhabi-based carrier Etihad Airways said it reduced carbon emissions by 3.3 per cent year-on-year in 2017 by retiring several older aircraft and switching to new, more fuel-efficient models.
However, such tactics may not be enough on their own, Mr Van Manen says. “The next major gains will most likely come from more sustainable energy sources for powering aircraft."
These could include using biofuels from renewable sources and electric planes. He says it is too early to predict electric planes' share of the global aviation market. “The market for civil aircraft worldwide is often valued at close to $500 billion a year, so even if only a modest share of the overall aviation market adopts this technology, the business case is still exciting,” Mr Van Manen says.
Norway, western Europe’s largest oil and gas exporter, has pledged to cut total emissions of greenhouse gases by 40 per cent by 2030. The country is one of the first with a national strategy to pioneer electric flight – it wants all domestic flights to be fully electric by 2040.
In June, local airline Wideroe carried then-transport minister Ketil Solvik-Olsen and Dag Falk-Petersen, chief executive of the country’s airport operator Avinor, on its inaugural two-seater electric plane as part of plans to launch its first commercial electric aircraft within the next decade.
"The development of electric aircraft is driven both by the ambition to reduce greenhouse gas emissions and lower the cost of air traffic," Mr Falk-Petersen tells The National.
Nearly all of Norway’s electricity comes from renewable energy sources. It has a network of short runways and short-haul airports, government and stakeholder support and a proven track record for electrifying road transport, he says. “We believe Norway is well suited to also partake in the development of electric aircraft.”
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Some of the world’s best-known aircraft and engine manufacturers are also investing in research and development of electric planes and even Nasa is said to be looking into electric-driven flight.
German technology giant Siemens has partnered the France-based plane maker Airbus to introduce regional electric aircraft by 2028. Beyond 2035, the partners plan to have a short-range aircraft such as the A320 operating with a power range of 20 megawatts.
"If [airlines] want to grow, they need an alternative to current technology otherwise they'll stagnate," Johannes Wollenberg, who is part of Siemens' eAircraft team developing hybrid electric propulsion systems, told The National last month.
Boeing, meanwhile, is developing hybrid-electric aircraft technology for journeys of 500 miles or less with capacity for 5 to 9 passengers, while its venture capital arm, BoeingHorizonX, has made minority investments in aerospace and manufacturing start-ups. These include Zunum Aero, which is on track for delivery of its first electric aircraft in the early 2020s.
Its first customer is JetSuite, a private aviation company that has ordered up to 100 electric aircraft for its fleet.
"We plan to democratise regional high-speed travel by offering operating costs that are 40-80 per cent lower than current regional aircraft, with added environmental benefits," Sandi Adam, chief marketing officer at Zunum Aero, tells The National.
Logan Jones, senior director at Boeing HorizonX, says the unit is exploring systems to enable “attainable, affordable and sustainable regional air travel”.
Electric-powered planes are still in the early stages of development and will require years of research and technological advances before becoming mainstream, Mr Van Manen says. Currently, electric batteries generate a lot less energy than burning kerosene, the standard fuel used to power aircraft, although battery technology is developing. “The gap is narrowing,” he said.
Even with the recent improvements in technology, there are still constraints to larger commercial aircraft using electric batteries in the foreseeable future. “The future of electric aviation will depend on sufficient access to renewable power to recharge aircraft and batteries,” Mr Van Manen says.
It could be decades before the new planes enter commercial fleets and even then, the limited range means they will probably be for short-haul flights more suited to charter and regional airlines, analysts say.
This is one of the reasons why demand from some airlines has been muted so far. Dubai-based Emirates, the world’s biggest airline by international passenger traffic, relies on long-haul routes for its bread and butter. “At this time, there are no plans for investment in electric aircraft,” an Emirates spokeswoman says.
Strata, Abu Dhabi’s composite plane parts maker for Boeing and Airbus, is not negotiating contracts for electric aircraft parts, says Ismail Ali Abdulla, chief executive of Strata. IAG, the parent of British Airways, says only that it welcomes technological developments that improve the industry’s performance in cutting carbon emissions and noise.
Iata does not see electric planes as contributing hugely to the industry’s carbon reduction goals. “Elements of hybrid technology may well be introduced in the coming decades, but the main prospects for reducing emissions will come from lighter materials, better aerodynamics, more efficient jet engines, and sustainable aviation fuels,” an Iata spokesman says.
Infrastructure remains one of the biggest barriers to adoption of electric planes. Reliable access to renewable energy sources to charge aircraft and airport redesign to accommodate high-voltage grids will be required.
Zunum Aero says while it does not anticipate major regulatory hurdles, it still needs infrastructure support at airports including charging stations and space for battery swaps. Regulators must also address safety and certification issues for new technologies and systems, while manufacturers must consider whether planes are autonomous or piloted.
“Any progression with electrical propulsion will require airworthiness certification, as well as broad regulatory acceptance for enabling technologies such as high-powered batteries,” consultancy Roland Berger says in a report.
New regulation will also need to address cyber security threats related to the new technology and autonomous flight systems, the report says. Practical safety rules will need to address air traffic control infrastructure and airspace management.
Avinor acknowledges there are regulatory issues to be addressed but says none are “major hurdles,” and it believes electric planes will need to meet the same safety regulations as conventional ones.
Icao says it is “closely monitoring” research and development in electric propulsion so it can support the entry of these new technologies for the benefit of airlines and consumers.
Although electrification of planes seems a harder nut to crack compared to cars and other industries, indications suggest aviation will follow suit.
“It is not a question of if, but when,” Roland Berger's report says.