
Airbus and Boeing are exploring the viability of electric planes - dnetesn
https://phys.org/news/2018-04-global-aviation-aims-green.html
======
kzrdude
Norway is in an ideal position; a surplus from oil money and excessive access
to hydro power. I would hope they can use their current oil prosperity to
prepare for a hydro (and other green energy) powered future, in all kinds of
new places.

After I typed that I realized that the whole world could be said to be in oil
prosperity still, so the same applies to us all: with less evenly distributed
oil prosperity, and not every species of green energy available everywhere.

~~~
FiveSquared
But that will never happen in the USA due to the influence of the oil
industry.

~~~
ubernostrum
You may be interested in the Norwegian TV series "Occcupied":

[https://en.wikipedia.org/wiki/Okkupert](https://en.wikipedia.org/wiki/Okkupert)

The premise is that Norway develops thorium reactor technology and ceases all
fossil-fuel production. And then is clandestinely and later openly invaded by
Russia, with the blessing of other countries, to seize oil and gas production
facilities and forcibly re-open them.

~~~
sitkack
Oil is always a liability. It would be better to claim you ran out. But the
Russian subearth nuclear boring machines don't need to invade.

~~~
na85
>Russian subearth nuclear boring machines

The what now?

------
cagenut
If you're interested in the electrification of flight check out this episode
of Fully Charged:
[https://www.youtube.com/watch?v=Xe1g1JrRRkY](https://www.youtube.com/watch?v=Xe1g1JrRRkY)

Its kindof like a "roadster" for the sky.

I was really impressed by the contra-rotating prop opportunity that becomes
possible because of how small electric engines are (for their power).

~~~
mrfusion
I feel like it would chop up The air too much for the second propeller?

~~~
andlier
The issue with the «chopping» is noise level. Counter rotating propellers are
more efficient than a single propeller. «Contra-rotating propellers have been
found to be between 6% and 16% more efficient than normal propellers.»
[https://en.m.wikipedia.org/wiki/Contra-
rotating_propellers](https://en.m.wikipedia.org/wiki/Contra-
rotating_propellers)

------
savrajsingh
It’s just a question of the energy density of batteries vs. fuel. We need a
couple more battery breakthroughs before we get a fully electric commercial
airliner.

~~~
GuB-42
There is more than that. Planes become lighter as they burn fuel, batteries
don't become lighter as they drain.

Lighter planes are more efficient, and most airliners are not designed to land
with their tanks full. They have a option to jettison their fuel in case of
emergency.

It means that just matching the energy density of fuel is not enough,
batteries must exceed it. Jet engines are also quite efficient: around 40%
now, and it may reach up to 60% in the future. It means that the more
efficient electric engine is less of an advantage compared to cars for
example.

The only battery technology that seems viable in order to replace fuel would
be lithium-air. Petrol is just too good at storing energy.

Right now, I'd say the only chance for a "zero-emission" plane would be using
biofuels.

~~~
bigiain
I'm pretty sure the "emergency fuel jettison" is for "I'd rather it not splash
about everywhere and catch fire in the case that I put this plane down hard
enough to split the tanks open" rather than "It's impossible to land this
plane safely at the same weight as it took off".

(Not that I'd want to be hurtling at the ground barely in control with many
tons of fully charged LiPo battery on board either...)

~~~
hueving
Nope, look at the difference between the MTOW and MLW columns here:
[https://en.m.wikipedia.org/wiki/List_of_airliners_by_maximum...](https://en.m.wikipedia.org/wiki/List_of_airliners_by_maximum_takeoff_weight)

The issue is the brakes overheating and the impact on the landing gear.

~~~
bigiain
Thanks! Yet another thing to add to "the list of stuff I'm wrong about"... :-)

------
cyberferret
The stat that really woke me up to how popular travel was when an aviation
magazine once posted that at any second of any day, there are at least one
million people flying in an airplane somewhere.

That's an entire good sized city full of people who are not in contact with
the ground at any point in time you care to pick. And that article was quite a
few years old, I wouldn't be surprised if that number has increased
significantly lately.

That should bring some perspective to the environmental impact of transporting
that many people around the globe.

~~~
FabHK
It's said that 1000+ Boeing 737 alone are airborne $NOW.

~~~
Someone
That’s likely true. They produced the 10,000th 737 in March, so if each plane
were airborne eight hours a day (not unrealistic for commercial planes), two
thirds of all 737s produced could be out of service to get at that 1000 ⇒ I
would guess that actual number is closer to 2000, possibly even over iT.

------
lumberjack
It would make infinitely more sense to look into carbon neutral hydrocarbon
fuels that could be used in conventional turbofans.

Some more material on this topic:
[https://aviation.stackexchange.com/questions/26910/could-
an-...](https://aviation.stackexchange.com/questions/26910/could-an-electric-
engine-provide-the-same-performance-as-jet-engines-on-current)

~~~
ShorsHammer
Another SE link of interest, how much electrical power needed to run a 747
engine:

[https://aviation.stackexchange.com/questions/19569/how-
many-...](https://aviation.stackexchange.com/questions/19569/how-many-
kilowatts-to-get-an-electric-747-8-airborne)

The consensus is ~90 MW.

That's a lot of energy, electric air travel is certainly possible, but it will
likely come at a severe cost to speed and endurance.

If we are going to travel slowly would personally prefer autonomous airships.

~~~
TheSpiceIsLife
Megawatts is a power unit. To sustain 90MW for a 4hr flight you need a battery
that can provide 360MWh of energy.

Anyone care to do the numbers on how much a lithium ion battery would weigh to
be able to deliver 360MWh, and remember if you want to use it more than once
you can full charge no discharge it.

~~~
Hextinium
A standard lithium ion battery has between 100-265 Wh/kg if you need 360
thousand to 135 thousand kg of lithium ion batteries plus probably a few
thousand for charging equipment. A a 747 has capacity for about 45k kg of fuel
so a factor of 4 improvement is needed before that is comparable.

~~~
ShorsHammer
The energy density of most fossil fuels is still far beyond anything we've
managed through incremental improvement on 1900's battery technology.

There's much more work to be done.

------
DelaneyM
The only plausible near-term renewable-energy flight option I can see is
hydrogen fuel cells powering electric planes.

The equipment is heavy, but compressed liquid hydrogen is both producible from
renewable sources and has a significantly higher energy/weight ratio than
traditional fuel. It would require a few advances in fuel cell technology, but
that's totally plausible.

------
cm2187
As a first step, they could make at least the take off and landing electric,
that would help a lot with the noise and pollution around cities, i.e. where
people live. I guess the batteries could be recharged during the flight for
landing.

~~~
pjc50
Takeoff is the hardest part requiring the most power, unfortunately.

~~~
dragonwriter
> Takeoff is the hardest part requiring the most power, unfortunately.

So, we just need a catapult system for commercial aircraft (like used on
aircraft carriers, only lower acceleration since you are doing it to reduce
the amount of energy needed from the engines, not to shorten the take-off
distance.)

~~~
dalf
Why not something similar to railgun but at a slower speed.

This would involve few things on the plane.

The draw back is that airports needs to install this system.

During take off, if there is a problem, the system could be stopped.

Perhaps it's not usable in this context ?

~~~
dllthomas
Magnetic media on the plane might be unhappy.

------
agumonkey
side note: a few companies are also bringing back zeppelin, so far for
freight/cargon (10s of tons) but also but slow public transport. Hindenburg
drama aside, I find them superbly peaceful.

see:
[https://www.youtube.com/watch?v=oxotOEZCh8g](https://www.youtube.com/watch?v=oxotOEZCh8g)

~~~
wongarsu
I can totally see them in helicopter-like roles for heavy cargo. I have my
doubts about the viability of public transport.

In the times of the Hindenburg the zeppelin was already becoming obsolete. If
you wanted comfort ships could provide much more because weight was a major
issue for zeppelin interiours, and if you wanted speed planes were already
several times faster. The high number of crew combined with slow speeds (i.e.
long travel times) meant that zepellin tickets weren't cheaper than either of
the two alternatives.

With both ships and planes significanlty better than 80 years ago I don't see
how economics should be more in favour of zepellins now. There's novelty
value, but that didn't keep the Concorde flying either.

~~~
agumonkey
Depending on the price and some safety stats, I think I'd be very willing to
take slower trip in a modern zeppelin. Just for the passiveness (for my own
comfort and the lower energy requirement for the environment) of it.

------
Alyosha_
I can see playing and winning against ICE with electric motors, but against
the efficiencies of a turbine? Ummmm....

~~~
nine_k
Electric engines are about 98% efficient.

What's hard to beat is the energy density of kerosene.

------
hyperpallium
It's weird, recently a solar plane circumnavigated the globe, but got very
little publicity.

~~~
bpicolo
You can't scale up solar power to an aircraft carrying significant passengers
/ cargo.

~~~
lucb1e
Do you have anymore information on that, a link perhaps?

~~~
kurthr
The weight for the mass of the passengers scales with the volume (m^3) while
the area of the solar cells (and wing) to lift them scales with m^2. The
typical solution for human scale aircraft is to fly faster (higher stall
speed) and extend the length of the fuselage. Unfortunately, that combination
doesn't increase efficiency so you end up needing even more fuel (or area and
weight for batteries and PV).

The demonstrated PV aircraft are already pushing the lowest wieght, lowest
drag wings with the highest efficiency PV and energy dense Batteries. This is
a case where bigger is harder (not so with Zeppelins where structural material
weight/stiffness scale to much larger sizes).

------
kwoff
I'm not sure how on-topic this is, but this story/topic reminds me of the
latest from Isaac Arthur called "Portable Power":
[https://www.youtube.com/watch?v=ffXqcf48D9Q](https://www.youtube.com/watch?v=ffXqcf48D9Q)
That's not about electric power per se, but maybe a nice context/background.
If nothing else, in the first 2 minutes I learned something that I (who
studied physics) hadn't even considered: that the electrical words "battery"
and "charge" come from artillery terminology!

------
exebook
Article says that the electric powered planes need shorter runways, why is
that?

~~~
Zhenya
Instant maximum torque most likely.

I guess they are assuming equal or less weight for the plane

~~~
mveety
Yeah the torque is probably the reason. From experience, if you stand on your
brakes and throttle to take off power then let go your take off performance is
better. It's part of the short field take off procedure.

------
reacharavindh
How about Hybrid planes?

Take a conventional Dreamliner or A320, and add batteries and electric
engines. Plane takes off using fossil fuel (hard to electrify), and then
switches to electric engines once at cruise altitude. This is best of both
worlds, and provides additional redundancy...

~~~
mrfusion
I’d actually suggest the opposite. Planes cuuently need overpowered engines
just for take off

~~~
ams6110
It will still never make sense until battery energy density increases a lot
more. Boost power for takeoff is still going to be cheaper weight-wise burning
kerosene than with electric batteries.

~~~
m_mueller
How much of a Tesla‘s battery is drained after a drag race? Electric seems to
be quite good at delivering boost. See also the current generation of
supercars from Porsche, Ferrari and McLaren.

~~~
icegreentea2
The problem is that then the battery and the entire electric half of the
hybrid system is then deadweight for the rest of the flight.

Now that doesn't mean it's not viable, but it's going to be a difficult
calculation to make without actually have specs in front of you.

The catapult solutions elsewhere in the thread seem to make more sense.

But once again we're all back to actually having to do the math on these.

Commercial flight is viable because the engineering safety factors and
economic margins are so close to 1. This means that changes actually have to
be considered carefully, unlike some other fields where the greater safety
factors and margins let you get away with more assumptions.

------
jopsen
From an engineering perspective how much harder would be to do a cross
Atlantic high speed rail: Norway <-> Canada ?

Politically, it would probably be possible due to cost and risks.

~~~
pjc50
The Channel Tunnel cost ~£200m per mile. The Atlantic is ~4000 miles across.
That implies the Atlantic crossing would cost £800bn, slightly more than a
trillion dollars and roughly the cost of the Iraq war and occupation.

~~~
taf2
Not sure the cost would be linear either since the Atlantic floor is probably
deeper in certain sections

------
FiveSquared
A related YouTube video about the subject:
[https://youtu.be/ql0Op1VcELw](https://youtu.be/ql0Op1VcELw)

------
hanklazard
For anyone not aware, YC grad Wright Electric is in this space:

[https://weflywright.com/](https://weflywright.com/)

------
realPubkey
Or we just stop flying arround the world for two-day trips.

~~~
sjilo
I think we should now be at a point where we realize that people won't give up
these benefits to their lives "for the greater good". Convincing people to go
green as a business model would be a huge failure - nobody would pay to get
convinced to stop doing something convenient.

~~~
geff82
That is what I always say! Teslas, for example, are not becoming so popular
because their owners are all environmentalists. They got so popular because
they are extremely fun to drive and save on fuel a lot while not restricting
their owner in range. I for example, recently reserved a Model 3, but I would
not stop flying. But I would choose the airline that first provides me with a
calmer and less smelly airplane any time. Ä

------
Apocryphon
Musk-Stark efforts bear fruit?

[https://www.youtube.com/watch?v=Y9BUcjuW-
_A](https://www.youtube.com/watch?v=Y9BUcjuW-_A)

------
toomanybeersies
Airbus actually made a prototype electric ducted fan plane:
[https://en.wikipedia.org/wiki/Airbus_E-
Fan](https://en.wikipedia.org/wiki/Airbus_E-Fan)

The core problem with it though was the poor energy density of batteries.
Hopefully electric cars will drive more innovation in this area, although the
aviation industry is usually at least 20-30 years behind the automotive
industry as far as engine technology goes, so we're probably 40 years away
from getting widespread adoption of electric aircraft.

~~~
Retric
> behind the automotive

That's far from true, large aircraft engines are vastly more efficient than
automotive engines. Small aircraft are such a tiny market they effectively get
zero R&D.

Interestingly hybrid cars could be significantly improved fuel efficiency
using turbine engines though at increased costs. Plug in hybrids may actually
see the adoption due to lower weight and lower useage making those tradeoffs
less meaningful.

