Airbus and Boeing are exploring the viability of electric planes
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phys.org
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.
It wouldn't surprise me if we were at 90% at one point, but at least according to this: https://wdfw.wa.gov/conservation/habitat/planning/energy/hyd..., we're presently only at 75%. Your point still stands - we have a lot of hydro here, and an increasing amount of wind power, especially in Eastern Washington. I went to look into it because I'm always surprised how much of my own (Pacific Power) bill is from coal / non-renewable sources, given that I live within an hour drive to the Columbia and am surrounded by wind farms. I'm told at one point in history (1970s?) Grant county in WA and Umatilla county in Oregon had the cheapest power in the country and were on some kind of 99-year price freeze, all from hydro, but I don't know the specifics.
Not at current levels of consumption and production.
We are about 98% hydro now and it's probably going down as more people use more energy.
But you are still correct, Norway is the ideal country to try this and it is an explicit aim of the government now to have all short haul flights electric by 2050. We already have electric ferries on the fjords, electric buses, and, of course, a lot of electric cars (more than 100 thousand electric cars in Norway now).
Hydro power is an impossible resource to perpetually manufacture more of. The US has heavily tapped out its potential in hydro. First it's difficult/undesirable to manufacture a new source of hydro once you reach saturation, and second it's arguably a terrible idea to do so when you have good alternatives to damming up a natural water flow.
The US is the world's #2 nation in wind energy production and is adding more wind capacity per year than any other nation not named China.
Let's put it into context with the parent's comment you're replying to:
Norway had 1,162 MW of wind capacity in 2017. The US had 89,077. That's a 76 fold gap. However there is only a 63 fold gap in the population size between the two nations.
Given Norway has a meaningfully higher GDP per capita than the US (~15-20% higher typically), it looks even worse when you consider the GDP per capita vs wind energy capacity per capita ratio.
The US exceeds the vast majority of all countries on per capita wind energy capacity, including Japan, Australia, New Zealand, France, South Korea, Italy, Belgium, China, Greece, Turkey, Taiwan, Poland, Mexico, Brazil. Overall the US is doing OK with renewables and keeps getting better by the year. It's obviously important that that trend remain intact.
As for why a country with vast access to hydro would prefer wind energy, Hydro requires large investments, is excruciatingly difficult to upgrade, interferes with local water flow and ecosystems, and in the case that either it is improperly maintained or a major accident occurs, can be very dangerous and deadly.
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.
The what now?
You mean more bonkers than letting EDF and the Chinese do it?
E.g. Uber
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).
Did that really have to do with the electric motors? They even gave an example of a combustion engine plane that did the same.
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.
Flow batteries can and open cycle fuel cells do; electric isn't just the kind of batteries that retain reaction products.
(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...)
The issue is the brakes overheating and the impact on the landing gear.
Right, but they can be thrown overboard :-)
You climb out to cruise altitude - then drop off the "climb battery" which would autonomously return to your takeoff point (somewhere nearby where if can easily/safely land, be retrieved, and recharged for the next flight). You'd cruise to your destination on the "cruise battery", which you'd jettison near the landing point, so it could fly itself there for charging. You'd land with just the "landing battery" which'd have sufficient capacity for go-arounds and/or diversions, just like your fuel reserve in a conventional dinosaur-burning aircraft.
Dropping batteries off and moving the remaining ones around while maintaining safe centre of gravity might be tricker than just pumping liquid fuel around, but surely not insurmountable (the military seem to be able to jettison stunning weights of munitions while flying...) Perhaps youd got for batteries divided into six spread equally for and aft from the cog - and drop them in matched pairs?
That might work for disposable rockets launched from the south Pacific, but it does not work for a reusable aircraft flying over populated continents.
Then you just need a fleet of smaller planes to carry those drones.
[0] https://www.amevoice.com/blog/1058/airbus-a340-fuel-system-d...
Aircraft have been doing that forever. Carefully managing the fuel flow from which tank has always been a task for the pilot.
The Luftwaffe never figured out that they could have trashed the P-51s if they caught them early enough.
These days, that tank has been replaced by a passenger seat so you can get a joyride on a P51.
For short-haul flights, this matters a lot less.
Your criticism is similar to what many people said about electric cars and electric trucks. Well, surprise, commercial short-range cars and trucks became viable before longer-range cars and trucks.
yeah we can build them but looking back twenty years from now should be really interesting
Plus, they sound like pod racers from the future.
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.
A bit of Googling only turned up data for passengers on commercial airlines, so let's just do those for now.
At the end of 2013, according to the IATA, there were 8 million commercial passengers per day [1]. It looks like it has grown to about 12 million a day since then [2].
If the average flight is 2 hours or more, that would give an average of 1 million commercial airline passengers in the air at a given time. I didn't find any reasonable looking average world flight time data, but the impression I got is that 2 hours is probably in the ballpark.
But that's just an average. At times it will be above that, and at times below it. Given the number of people and flights we are dealing with, I think that variation above and below would be fairly narrow. Thus, I think it is plausible that if cargo, military, and others were included that would be enough to push it to always over 1 million.
[1] http://www.iata.org/pressroom/pr/Pages/2013-12-30-01.aspx
[2] https://www.statista.com/statistics/564717/airline-industry-...
Some more material on this topic: https://aviation.stackexchange.com/questions/26910/could-an-...
https://aviation.stackexchange.com/questions/19569/how-many-...
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.
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.
There's much more work to be done.
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.
Batteries don't provide that kind of mass reduction as they discharge, which means long-range flight using only batteries as a power source is rather unlikely.
I would have thought landing to be far less energy intensive (except perhaps in case of aborts, but I would imagine they're reasonably uncommon).
[0] https://en.wikipedia.org/wiki/EGTS
[1] http://aviationweek.com/commercialregiontabs-true/easyjet-te...
I don't know though how much the efficiency of current jet engine drops off at the far ends of their throttle range.
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.)
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 ?
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.
What's hard to beat is the energy density of kerosene.
The engineering and physics challenges are even tougher for passenger aircraft. It ain't gonna happen.
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).
I guess they are assuming equal or less weight for the plane
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...
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.
Politically, it would probably be possible due to cost and risks.
Traveling to anywhere in Siberia involves longer train journeys. Space is much cheaper in trains than it is in airliners and sleeping wagons with beds are relatively cheap in both European and Siberian trains. Restaurants are common in high speed trains. A 18 hour train journey can be vastly more comfortable than a 7 hour flight.
It would probably make more sense to go overland in the opposite direction, through Russia, Alaska and Canada.
Flying around the world for two-day trips isn't something that the great majority of the human population will ever do.
The whole flying experience was a lot better in the old days, when indeed flying was special.
Also, remember that still most people on this planet can't afford to fly (i.e., even under current conditions).
Finally, I wouldn't mind seeing less vacation pictures on Facebook, of the kind "look where I am now!"
I remember when Obama said "Gas under a buck ain't bad" (paraphrased) and was dismayed - you cannot pursue the goal of making something cheaper and reducing it's consumption without something like rationing (or, I suppose, simply making an alternative which is profoundly superior and cheaper, but we haven't got that)
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.
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.
Batteries will never get there, even in four decades. There's no known battery chemistry, even in theory, that even comes close. Fuel cells would have to be the power source, though fuel cells are like fusion in that they're always a few decades out.
Frankly if the real goal is having aircraft flying on renewable power, I'd put my money on using that clean energy at sea level to synthesize fuel to burn at altitude. Aviation just isn't a meaningful application of electric motors IMHO.