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Page added on October 10, 2017
A New Era for Aviation?
The pressure to reduce carbon dioxide emissions and the prospect of a world running largely on renewable electricity has sent research and development teams in every sector back to their respective drawing boards to look at options that might exist for electrification. Perhaps the most challenging sector is aviation, where liquid hydrocarbon fuels are the only form of energy carrier available (mainly of fossil origin, but with some bio-origin fuels now appearing). The dependency on hydrocarbons is due to their high energy density and the challenge with fuel to weight ratio that planes have. However, fuel costs can represent up to 70% of total costs for an airline, so the business model tends to focus on efficiency as a primary consideration. Efficiency isn’t just about the plane itself, but about maximising passenger load, minimising extraneous weight, limiting taxiing and air traffic delays, using electricity for power at departure gates and optimising routes.
In the light of all the above, the idea of electrification in aviation is tantalizing, but there is little sight of this happening. At one end of the spectrum there is the prospect of single person electric drone taxis for short hops in cities, but after that there is nothing, until last week. EasyJet, in conjunction with the startup, Wright Electric, announced that they hoped to be flying a short-haul battery electric passenger plane within a decade.
The concept illustration looks impressive, but is this really feasible? Battery energy density is a key determinant and it is moving rapidly in the right direction. The energy density difference between the traditional Lead-Acid battery, still the standard for starting most cars and the best lithium based batteries is nearing a factor of 10, but lithium based batteries are still a long way from Jet A1 fuel as shown in the table below. The difference in energy density on a weight basis is around twenty times, in favour of Jet A1.
| Jet A1 | Current Li-Ion Battery | Emerging Li-Metal batteries | |
| Energy MJ/kilogram | 42.8 | ~0.7 | 1.8 |
| Energy MJ/litre | 37.4 | ~2.0 | 4.3 |
Like an electric car, the efficiency of a battery electric aeroplane would be significantly higher than the combustion engine equivalent, although the starting point for a modern jet engine already exceeds that of vehicles. The chart below (IPCC Report on Aviation 1999, chart from 1991) shows that overall efficiency of jet aircraft falls in the range 20-40%, but significant improvements have been made since then. A modern Boeing 787 would show an overall efficiency approaching 50% on the same chart.
Even with near 100% efficiency for the battery electric aeroplane, the energy density of Jet A1 still gives that fuel a factor of ten advantage. As such, it will be distance that suffers, given there is a weight restriction for aeroplanes.
I am a regular traveler out of London City Airport and often see the Embraer 190 plane, which is similar in size to the easyJet concept photograph distributed with their announcement. But the Embraer 190 has a range of over 4,500 km, so one tenth of this gets near to the 335 mile range goal mentioned by easyJet, ideal for the flight I often take from London City to Rotterdam. So on paper, this would appear to work, but a plane with a range limit of a few hundred miles might significantly restrict the operational flexibility that airlines enjoy; for example, it couldn’t be swapped at short notice for a London City to Rome flight, should that be necessary.
Battery electric planes also bring with them a particular design change – apart from the obvious. Currently, planes land some 20% lighter than they take off, as they burn the fuel. With battery electric planes, they will land heavier than they take off, because the discharge of the battery means oxidation, meaning it gains mass. This will require very different landing gear.
Another facet of the EasyJet announcement is the desire to see these planes carrying passengers within 10 years. Given that the plane is concept only and doesn’t come from an existing family of similar planes, this may be ambitious. The 787 Dreamliner was announced in concept by Boeing in early 2003, finally receiving certification in late 2011. That’s nearly nine years for what is essentially a new version of an existing product, albeit with some significant changes such as the use of carbon fibre in the fuselage. But the 787 then had problems with its battery system for on-board electronics, leading to a temporary grounding and eventual regular flights from April 2013.
The 787 was not Boeing’s first attempt at a new aircraft following the 777 series. In the late 1990s it started development of the Sonic Cruiser, releasing a concept proposal in March 2001. With aviation business models changing rapidly at that time, Boeing abandoned this concept and instead moved to the 787, but this evolutionary process still consumed valuable design years. At least from one perspective, it could be argued that the 787 took over 13 years to go from concept to regular use.
The Wright Electric concept represents a revolutionary change in aircraft design and propulsion, so there is every chance that this may take longer than anticipated to get going. It will require extensive certification and testing by airlines, airports and the aviation authorities and may go through more than one design iteration, depending in part on the evolution of battery technology and the resultant changes in energy to weight and volume ratios. The story of the Mitsubishi Regional Jet is outlined here, and is a saga of changes and delays spanning 17 years. It is a conventional jet aircraft, but represents a first for Mitsubishi for a very long time.
A further ambitious aspect of this project is the notion that a start-up can take on the likes of Boeing and Airbus and find the necessary investors to back what is typically a multi-billion dollar investment in design, engineering, prototype development, manufacturing, testing and certification of a new aeroplane.
Behind all this is the pressing need for electrification across society, so this type of thinking and risk taking is essential. The question that remains though, is whether I will be able to ride in such a plane from London City Airport before 2030.
15 Comments on "A New Era for Aviation?"
Go Speed Racer on Tue, 10th Oct 2017 7:00 pm
Kool. It won’t have to crash to
catch fire. A Lithiim battery fire will
burn it up before the chunks hit the
ground.
Did everybody also know the Lithium
batteries don’t work below freezing.
This scam is right up there with fusion.
The modern jet airliner is a miracle and
it’s the fossil fuel that makes it work so well.
dave thompson on Tue, 10th Oct 2017 8:20 pm
Oh boy only ten years away just like fusion we are saved.
Cloggie on Tue, 10th Oct 2017 10:30 pm
Declassified NATO study from 2012 on electric flying, a little skeptical but they don’t rule it out:
http://tinyurl.com/y8vh2l4s
Cloggie on Tue, 10th Oct 2017 10:37 pm
That was 2012, now electric flying does work for flights up to 365 km, 4000 m altitude:
https://deepresource.wordpress.com/2017/08/08/electric-flying/
On a larger scale a hybrid solution could work: fossil fuel to give the plane speed and altitude and electricity for the horizontal part of the trajectory. The last 150 km descending part is for free anyway.
Anonymouse1 on Wed, 11th Oct 2017 1:14 am
Who are trying to convince exactly cloggen-tard?
Cloggie on Wed, 11th Oct 2017 2:39 am
Stay out of this discussion BLM-punk, this is not your league.
All the big guys are working towards electrified flying. They would never stick their necks out if they knew in advance it wouldn’t work.
http://company.airbus.com/responsibility/airbus-e-fan-the-future-of-electric-aircraft/e-aircraft-roadmap.html
https://www.theguardian.com/business/2017/oct/06/electric-commuter-plane-backed-by-boeing-to-take-off-in-2022
makati1 on Wed, 11th Oct 2017 2:56 am
Cloggie all the deluded techie nuts “…are working towards electrified flying”. And I suppose that all of the fusion power techies are not also dreaming the impossible dream? They are “sticking their necks out” for cold cash. A paycheck that is never ending. Ditto for electric flying. A paycheck that keeps coming because they can dupe people like you forever into writing the check. You are old enough to know better than to believe all of that crap.
Cloggie on Wed, 11th Oct 2017 3:19 am
makati, you cannot compare fusion with electric flying. Fusion is pure tax money. Electric flying is largely corporate money. The latter can’t gamble too much. On top of that Airbus and Boeing have to move because of the Paris Accords. And electric flying works, “plane” and simple.
https://m.youtube.com/watch?v=Vr3dX2EClDg
And the entire world is hunting for better batteries.
Something will come out of it.
Anonymouse1 on Wed, 11th Oct 2017 4:01 am
Cloggen-fraud, answer the question, retard. Who are trying to convince? Kenz maybe? You’ve already converted him with your proselytizing, and no, we’re not talking Yahweh here, so you really have no left to convert with your endless hopium-laden drivel.
You’re a dumbass who doesn’t even know the difference between energy storage, and actual energy. So take your tantrums clogged-sphincter and hit the road already.
makati1 on Wed, 11th Oct 2017 4:49 am
Cloggie, you can dream all you want but physics says both are not possible. And you can bet Boeing, et al, are getting government subsidies to pay for the ‘research’. A paycheck for the scientist/engineers, nothing more.
BTW: you can hunt for unicorns also, but the chance of finding one is slim to none.
newfie on Wed, 11th Oct 2017 5:47 am
The final stage before collapse is mass delusion. The dying civilization on Easter Island used up their dwindling resources building giant statues to impress the gods. Industrial civilization indulges in techno-fantasies as overpopulation, resource depletion and climate catastrophe loom on the horizon.
Davy on Wed, 11th Oct 2017 5:53 am
I am not going to say mass consumer travel by large jumbo jets can’t be electrified someday. I am not saying it because I am amazed at some of the other achievements of renewable energy. Yet, if you understand the hurdles it becomes another long shot and for what?
I would say first do we need mass travel? Basic human wisdom should be employed and asking the simple question of should we be doing mass travel? We can still do boats and trains and be fine. They can easily be electrified and boats put to high tech sail, electric, and bio/steam. In fact this may be a good demand management strategy. We need to slow down and we need to powerdown considering the world of limits we are in and the aspects of CO2 production and associated pollution.
To be fair to cornucopians maybe not every aspect of modernism should be downsized. I believe every aspect should be but I am being fair here. Mass travel probably should be downsized. Mass travel is often a dubious waste of valuable energy and producer of pollution and a good place to start. Anyone in the airline industry I suspect flight will still be happening for many years so I am not attacking your livelihood. I also think to maintain some form of flight biofuels should be looked into but biofuels will not maintain the mass air travel industry we have today. Biofuels are not going to run our passenger vehicles nor mass air travel but it may maintain aspects of the air industry. Emergency services and military will likely be maintained at some level. Mass consumer flight to warm beaches needs to be downsized it is not essential for survival.
A large jumbo driven by batteries will surely take 10-20 years to upscale (if ever). The technology is not even there currently. The little two seater constantly reference by cloggie is just a glorified glider that has little relation to the dynamics of a large passenger aircraft. So, we need at least 5-10 years for the technology to be perfected and 3-5 for the testing and development before you put a few hundred passengers at risk. By then peak oil dynamics will have us in a new and different world of constraints. That’s a guess but a good one. Look at how long it took Boeing to do the partially composite 787. In the meantime you have an industry that will be struggling to maintain itself in the best of times. There is going to be little enthusiasm to dump millions into R&D for such an idea. It is not only the technology in the air it is the retrofitting of thousands of airports for electric flight. I think focusing on the priority of a grid that is significantly supplied by renewables is a better strategy for you to preach about. Flight is not a good topic.
pointer on Wed, 11th Oct 2017 6:24 am
Meh. The world cannot afford business-as-usual, and it cannot afford to replace BAU with some “equivalent”. I fear that between now and some point in the future, the bills will come due, and there will be a dramatic depopulation by some unspecified process. At that point, all the issues so hotly debated here will be moot. The silver lining then will be that humans will return to living sustainably, but picture something like Planet of the Apes with bands of humans in place of the bands of apes.
GregT on Wed, 11th Oct 2017 11:10 am
The airline industry has had a long history of bankruptcies, mergers and acquisitions, bail outs, government subsidies, tax breaks, and back room deals, and is completely reliant on economies of scale. While the electrification of commercial aircraft might be a possibility, this is yet one more example of failing to see the forest through the trees.
Mankind’s future does not include electrojetsetting around the globe. The humans would be much better served if they focussed on more pressing issues, like population overshoot, loss of biodiversity, environmental degradation, and food and water security.
Any semblance of BAU will do nothing more than exacerbate all of mankind’s greatest predicaments. Long term there will be no techno utopia, but rather the survival of the fittest, if anybody can survive at all. Which at this late hour, is questionable to say the least.
Shortend on Wed, 11th Oct 2017 12:02 pm
The rate of aviation expansion is beyond reason. Total lack of reality. Most major airports have continuous projects of expansion.
Saw a projection that it will double by 2050.
Sure it will, mainly angels going to the great beyond…