Why Boris’s zero-emission long-haul British aircraft is just pie in the sky
Date added: July 2, 2020
The prime minister’s call for Jet Zero on Tuesday may owe more to his fondness for a punchy slogan than any realistic view of how UK aviation might develop in the next 30 years. His wish for the UK to build long-haul zero- emissions plane may never be achieved. It is just not credible. Short-range electric flight is, for the very smallest planes, already a reality. Multiple firms, including UK start-ups, are working on zero-emission eVtols – electric vertical take-off and landing craft, or flying taxis – for domestic inter-city travel, carrying just a handful of passengers. Battery weight and range means that manufacturers currently view larger electric planes as feasible only for short-haul flights – and even then the focus is largely on hybrid-electric, with jet fuel needed for take-off. The big UK contribution to this vision, a Rolls-Royce-Airbus collaboration called the E-Fan X, was dropped in April. Meanwhile, work continues at Cranfield university and elsewhere, trying to convince sceptics that hydrogen could eventually be a viable fuel for passenger jets, produced using surplus (?) renewably-generated electricity. Or combined to produce an “electro-fuel” – but that still emits CO2 when burned in a plane engine. . Tweet
Why Boris’s zero emission aircraft may be mission impossible
Johnson’s vision for the UK to build long-haul Jet Zero aircraft may never leave the ground
The prime minister’s call for Jet Zero on Tuesday may owe more to his fondness for a punchy slogan than any realistic view of how UK aviation might develop in the next three decades.
“We should set ourselves the goal now of producing the world’s first zero-emission long-haul passenger plane,” Boris Johnson said. “Jet Zero, let’s do it!”
But as far as the technology goes, Johnson might have more luck building a garden bridge to France than getting British-made, long-haul, zero-emission passenger planes in service before 2050.
Battery weight and range means that manufacturers currently view larger electric planes as feasible only for short-haul flights – and even then the focus is largely on hybrid-electric, with jet fuel needed for take-off.
The big UK contribution to this vision, a Rolls-Royce-Airbus collaboration called the E-Fan X, was quietly canned during lockdown.
EasyJet, should it survive, has long spoken of its hopes for a short-haul electric regional plane, and engine trials with a partner in the US, they say, have been encouraging.
Meanwhile, work continues at Cranfield university and elsewhere, trying to convince sceptics that hydrogen could eventually be a viable fuel for passenger jets.
Plants to produce synthetic jet fuels could be part of a net-zero mix (although not zero-emission when burned in flight). Low-emission flight – rather than no-emission – is currently the overwhelming ambition of civil aviation engineers.
Johnson’s target for a UK-built long-haul zero-emission plane before 2050 may, alas, swiftly crash-land with reality.
‘Jet Zero’: PM targets world’s first ‘zero emission long haul passenger plane’ in UK
30 Jun 2020 By Joseph Flaig (Institute of Mechanical Engineers)
Prime minister Boris Johnson has set a target of producing the world’s first “zero emission long haul passenger aircraft” in the UK.
He made the ambitious call during his ‘New Deal’ speech, setting out plans to “rebuild Britain and fuel economic recovery” after the coronavirus pandemic.
“As part of our mission to reach ‘net-zero’ CO2 emissions by 2050, we should set ourselves the goal now of producing the world’s first zero emission long haul passenger plane,” he said. “Jet Zero, let’s do it.”
People hoping for a quick and easy solution to aviation emissions will be disappointed, however, as the technology is far from ready. Electric planes have flown in the UK and abroad, but initial projects are based around small passenger numbers and relatively short regional journeys. The Eviation Alice, for example, has nine seats and a forecast range of 1,000km.
Other efforts have failed to make substantial progress towards zero-emission flight. Airbus and Rolls-Royce’s E-Fan X project, which would have initially used one electric motor before potentially electrifying further, was recently cancelled.
Energy density is the main challenge for zero emission flight. Hydrocarbon fuels store many-times more energy per weight compared to the best batteries, making them much more suitable for large planes for the time being.
Carbon neutral flights are a long way off, wrote aerospace expert Steve Wright from the University of the West of England in Professional Engineering earlier this year: “Without an absolutely astonishing physics breakthrough, we can’t expect even a regional electric jet until about 2035. I don’t expect the first electric transatlantic passenger flight until about 2050.
“The shame about hydrogen fuel cells is they’ve got more efficiency but about the same level of complexity as conventional internal combustion engines, while current biofuels are almost more environmentally damaging than fossil fuels, thanks to deforestation and palm oil growth.”
Other ‘green’ and engineering-focused measures in the prime minister’s speech included announcements on battery ‘gigafactories’, electric vehicle supply chains and carbon capture.
“Net zero is an extremely tough but necessary target, and the future of the UK’s decarbonisation and path to net zero is contingent on key decisions made by the government during this parliament,” said Sir Jim McDonald, president of the Royal Academy of Engineering. “Three decades is a very short time to completely renew, upgrade, install and secure entire parts of the UK’s national infrastructure but if government is willing to take a truly holistic view of the system, then the engineering community stands ready to deliver on the promise and potential of decarbonisation.”
Electric flying not feasible for larger planes or longer distances
July 3, 2020
There has been a lot of mention in recent years about the possibility of planes being powered by electricity. That has the potential to cut the CO2 emissions of aircraft. However, the aspiration of electric planes is likely to be a dangerous diversion from taking measures now to cut the CO2 from the sector, if it has the effect of creating the false hope of breakthroughs. The reality is that flying needs a very energy-dense fuel, such as kerosene. Currently there are some tiny planes, able to carry under 10 passengers, that may be able to make short flights, of under 1,000 km, in the next few years. That is entirely different from a passenger plane carrying 200 passengers many thousand miles. Power is particularly needed on take-off, and while climbing. Liquid jet fuel is burned during the flight, so the planes lands lighter than when it took off. The battery is the same weight throughout, putting more stress on the plane while landing. The engines would have to use propellers, and not be jets – and there are limits on how fast propellers can turn. There are real constraints, caused by physics, in the ability of electricity to power larger aircraft.
Airbus and Rolls-Royce have ended a joint venture to produce a hybrid-electric airliner test model
April 29, 2020
It seems the plans for a (pie-in-the-sky) electric plane before too long are even more remote than they were before … Airbus and Rolls–Royce have ended a joint venture to produce a hybrid-electric airliner testbed that could have paved the way for electric aircraft of the future. [A testbed aircraft is an aeroplane, helicopter or other kind of aircraft intended for flight research or testing the aircraft concepts or on-board equipment. These could be specially designed or modified from serial production aircraft.] The aim was to replace or or two of four jet engines with an electric engine. There is an unrealistic hope in the industry, and by some politicians, that aircraft carrying hundreds of passengers on their holiday etc trips will, in the not too distant future, be able to fly just on electricity. The reality is that, at best, there might be planes that can carry rather few passengers for rather short distances. Electric planes will NOT be able to substitute for planes like A320s now, travelling over 1,000 miles. The joint venture presumably was not sufficiently successful that the companies felt the need to continue with it. They did manage to produce a keg-sized 2.5MW generator, smaller than produced before.