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.
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
How do you propose keeping something cheap while ensuring only a small amount is used? Rationing?
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)
Since you believe in it, I guess it might convince a few people. But before I become nothing I want to travel as much as I can, be it two days at a time or two years at a time.
Jetlag :( It's kind of sad that regardless of technology and money there is no way, and there might never be a way to just hop on from SF/Tokyo to Paris for a weekend and back, and enjoy it.
I would love to not travel to go meet a client on the other side of the world. Unfortunately that’s often how business still needs to be done to win over the decision makers.
with sufficient taxes, maybe the cost of doing business on the other side of the world would be too high and you would just lose this contract to a local competitor. With sufficient taxes, many trips will just no happen.
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.
That is a huge positive aspect. Whenever anyone I know laments an air crash somewhere in the world, I just say to them "Right now, there are over 1 million people airborne, and who will arrive at their destination safely. The same will happen in 10 minutes, in an hour, in 6 hours, and tomorrow".
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.
Note that as written, it would include crew and passengers of commercial airlines, crew of cargo planes, passengers and crew on non-commercial flights, and passengers and crew on military flights.
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.
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.
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.
Off-topic, but still: There are several frightening realistic aspects with that series, but the key premise - that the U.K. would willingly allow Russia to take control over one of its energy sources - is so utterly bonkers that it spoils the rest.
I doubt it. My observation is that if there is an enormous amount of money to be made disrupting an established industry with practical tech, it happens. Money trumps law in many cases.
US wind energy production has increased eight fold in 12 years. The US has greater wind energy production capacity per capita than Norway does for example.
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.
I believe they specifically mentioned wind because that was the specific form of renewable energy the grandparent was talking about.
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.
It is not cost-effective to build much wind power in Norway, because of excessive cheap hydro power. Statoil and Statkraft build them in UK, where the price and subsidies are more favourable.
Norway is already well prepared for a green energy future. Statoil, their state-owned energy company, is a leader in offshore wind power and the whole country has been shifting to green power for some time.
Washington state gets 90 or so percent of its electricity from hydro. It isn’t that unusual, there are already a few hydro states in the world besides Norway, and one or two thermal states as well.
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.
It was great until the California energy crisis in the early 00s, then everything started breaking down as the grid acts to equalize pricing in the entire region. Still cheaper than California, not as cheap as it used to be :p.
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).
Harry Harrison covered this idea in “A Transatlantic Tunnel, Hurrah!” [1], which only had to compete with coal powered flying boats and nuclear trains.
The tunnel could be partially floating (or rather bridging over deep parts of the sea floor). Continental drift shouldn't be a big problem over a few decades, you will need some expansion joints anyways.
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.
The idea is full of problems, but what is the argument against 18 hour train journeys?
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.
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).
You can't do it with cars, either. Solar-powered cars are definitely a thing [1], but they're purely research vehicles. At 20% efficiency, PV cells will never power a practical car any consumer would want to buy. Nor would such cars likely be road-worthy on normal highways.
The engineering and physics challenges are even tougher for passenger aircraft. It ain't gonna happen.
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
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.
Probably related to Electric Ground Taxi System [0] which allows the APU(Auxiliary Power Unit, a small turbine driven generator) or potentially batteries to provide electrical power for taxiing. The APU also powers the air conditioning packs on the ground. The electric taxiing system was tested on Easyjet [1]
Now that electromagnetic catapults are becoming a thing, perhaps they can be adapted for airliner takeoff. One supposed benefit is the ability to adjust the acceleration profile to reduce airframe fatigue, and probably improve crew comfort at the same time. If it's smooth enough for passengers, it'd save carrying quite a bit of fuel and batteries.
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).
Not sure catapults are a great idea for commercial passenger service, unless they can handle rejected takeoffs in case of other mechanical problems on the aircraft. You don't want to be catapulted off the end of the runway if you have an engine failure shortly after the start of the take-off run.
That doesn’t sound fundamentally different from having a failure on one engine sufficiently late during takeoff. Either way you probably want your other engine to have enough power to make a landing?
Takeoff, and landing abort. It might turn out to be economical to have hybrid engines that are fully optimized (in efficiency and in drag) for sustained climb load (or even just to cruise) that can only deliver takeoff/abort thrust using electrical assist. It could be enough to carry batteries for no more than a few minutes of assist!
I don't know though how much the efficiency of current jet engine drops off at the far ends of their throttle range.
> 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.)
Landings are mostly idle power until they lower landing gears in the last few miles; Take-off with fuel load is the most demanding leg and also the hardest to electrify.
It's also worth noting that the range of an airliner depends heavily on the fact that it becomes lighter en route through burning fuel. At takeoff, nearly half the mass of the aircraft can be fuel.
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.
If you compare to hybrid cars, landing is more like braking to a stop light (unless you need to gun it again to abort the landing). Takeoff is like accelerating from a stoplight (where you need the most power). If electric could take over at any point, it would be in the steady cruise at altitude (akin to overdrive on the highway).
Going by your hybrid car analogy, electric would make most sense as a brief power boost on takeoff, allowing the aircraft to use smaller, lighter engines to cover cruising power requirements more efficiently.
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.
pretty much what many in motorcycling are waiting to see happen. a hundred and at most hundred fifty but that requires judicious use of acceleration and speed. cars and trucks can carry the mass but if anything screams "this tech isn't there yet" it is the weight to range ratio we have now in cars.
yeah we can build them but looking back twenty years from now should be really interesting
We’re getting there with motorcycles too- they are expensive but starting to get useable ranges with today’s battery tech:
http://www.zeromotorcycles.com/range/
You also expel all that burnt fuel reducing weight was you fly. Some aircraft even redistribute fuel between tanks to control stability and performance. [0]
A large gas tank was added behind the pilot's seat in the P-51 to extend its range. But it unbalanced the airplane, and made it difficult to fly. Pilots always drained it first.
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.
Actually the aux tank wasn't added to the Mustang purely for range. A big factor was helping to balance out the heavier Merlin engine. Pilots would typically leave about 1/3 of the tank to keep ideal balance and have an emergency fuel reserve. Typically by the time they had taken off and made the climb to altitude they had burned enough fuel from the aux tank (about half) to be in reasonable "fighting trim". Would've been pretty audacious for the Luftwaffe to try intercepting them that early in the mission, well within the range of every other USAAF and RAF fighter.
Interesting. I was told this by a former P51 pilot. He also said sometimes lone Ju-88s would sneak in at low altitude and pick off B-17s taking off or landing when they thought they were safe.
I’m sure the Ju-88 thing probably happened. IIRC there were at least a couple instances of caputured B-17s trying to slip into formations and shoot at damaged bombers, and there were definitely a few cases of captured allied fighters being used on bombers.
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.
I get the fuel cell concept: fuel (H2) and oxygen combine to make water, which is thrown overboard. But, I don't see how this pertains to flow batteries. Generally, the flow battery material (e.g. vanadium oxide) is highly toxic and/or reactive. Do you propose sending that type of material overboard?
I wonder if you could split the battery pack into thirds - each with a modern steerable parachute type glide-return system?
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?
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...)
If the landing speeds are the same, a heavier aircraft requires a longer landing roll. But a heavier aircraft also requires a higher landing speed. Those two phenomena compound.
It's possible to turn atmospheric CO2 and water back into hydrocarbons, which would make for a carbon-neutral, closed-loop fuel system. It takes extraordinary amounts of energy to do that, but improvements in that process, and/or the ability to generate energy more efficiently than we can now, would help.
Short high-traffic routes might be viable sooner. For instance, the Dublin-London route has 14,500 flights per year (highest in Europe), crossing about 400km. Mostly 737-sized planes, flying a tiny fraction of their full range. There are a number of similarly short/frequent routes in Asia. A specialized electric plane for this type of route would save a lot of CO2 emissions, and could come long before p, say, viable transatlantic electric planes.
So you're boldly predicting that you can't even build a short-range electric plane. Which is what everyone's trying to do.
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.
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.
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.
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.
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.
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.
I think we'll see smaller capacity VTOL aircraft for shorter flights before we get batteries with enough energy density for long-range flights. You'd just need to have a fast charging rate or potentially swappable batteries at landing pads. Daisy-chaining VTOL trips carrying 10-20 passengers ~100 miles at a time could be faster and more flexible. Uber has done some research on this too: https://www.uber.com/info/elevate/
When I last looked into this, I googled electric motors in the +30MW range and found that some gas pipelines use electric turbines of that power. These are massive, stationary engines which made me wonder if the weight of the motors might be an equally serious problem as the weight of the energy storage. Carbon neutral jet fuel really seems to be the simpler alternative.
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.
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.
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...
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.
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.
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.
probably a stupid question, but since theres landing gear anyway with drag, why can't electrical power be supplied through the wheels? I am thinking something like a tram, possibly with a bottom pantograph?
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.
If you'll recall, Boeing used pretty modern LiIon batteries in the B787 and it caused a few fires. That appears to have been a design mistake that no car manufacturer has made, but it still sets a standard for what aviation needs to do if they want to be closer to the bleeding edge.
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.
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
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!
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[ 2.9 ms ] story [ 110 ms ] threadThe 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)
And your solution is to see less of the world.
Since you believe in it, I guess it might convince a few people. But before I become nothing I want to travel as much as I can, be it two days at a time or two years at a time.
Flying around the world for two-day trips isn't something that the great majority of the human population will ever do.
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.
https://flightaware.com/live/aircrafttype/
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-...
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.
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
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.
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).
Politically, it would probably be possible due to cost and risks.
It would probably make more sense to go overland in the opposite direction, through Russia, Alaska and Canada.
[1] https://en.wikipedia.org/wiki/Tunnel_Through_the_Deeps
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.
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).
The engineering and physics challenges are even tougher for passenger aircraft. It ain't gonna happen.
[1] https://en.wikipedia.org/wiki/Sunraycer
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.
[0] https://en.wikipedia.org/wiki/EGTS
[1] http://aviationweek.com/commercialregiontabs-true/easyjet-te...
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).
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 ?
https://www.broward.org/Airport/Community/Documents/Stage3an...
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.
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.
For short-haul flights, this matters a lot less.
[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.
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.
Right, but they can be thrown overboard :-)
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.
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?
(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.
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.
https://weflywright.com/
see: https://www.youtube.com/watch?v=oxotOEZCh8g
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.
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.
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.
https://www.youtube.com/watch?v=Y9BUcjuW-_A
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.