Norway's Plan for a Fleet of Electric Planes
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The reason this is being pursued by so many companies is that electric planes solve a lot of problems and represent an enormous disruption to the aviation industry. Modern air planes are very complex and expensive to operate and need a lot of maintenance. The cost of operating them is completely dominated by fuel cost, maintenance overhead, and expensive taxes and fees at airports related to noise and pollution.
With electrical engines, all of this changes. They are light and simple and tend to have a long operational life with very low maintenance requirements. Recharging batteries is extremely cheap compared to burning tons of fuel (literally). Filling up an A321, which takes 24K liters of kerosene, will take you somewhere between 10 and 15K and gets you a range of around close to 8000 km. Most flights are much shorter than that meaning a lot of their weight and range is redundant. Also, you burn a lot of fuel on takeoffs and most planes need to get up high to get to an economical fuel burn rate to cruise. So you pay a huge price for getting all that weight up on every take off.
Electrical planes don't need to get up that high and can cruise efficiently at both low and high altitudes. Once cruising, operating them as a glider is actually feasible as well because you can safely turn the engines off and on again (unthinkable with a jet).
You avoid having to climb all the way up just so you're using up less of this very expensive fuel, which especially on short haul flights is a huge % of the whole flight.
Not actually economical in terms of energy used per distance covered, but more practical and likely to be appreciated by passengers? Less stress on the airframe too, probably.
If anything electric planes using their higher thrust will even climb quicker.
With a jet you will instead be optimizing fuel flow since that fundamentally drives your cost. That means taking the minimum amount of fuel you can get away with and the maximum number of passengers to ensure you actually recover the cost of the fuel you are burning.
The other (huge) advantages in flight safety and reduction in noise and overhead costs still apply, but I don't believe electrical planes will be as disruptive as portrayed without significant advances in battery technology.
This can include torbo props.
https://en.m.wikipedia.org/wiki/Propulsive_efficiency
Fuel has also a very big advantage over batteries and that is that you shed off weight when you use it while an empty battery will weight as much as a full one so you’ll end up carrying much more dead weight for the entire flight.
Fuel cells might be a possibility but I don’t think airplanes with hydrogen tanks are a good idea.
Additionally, as you said, storing hydrogen densely enough means pressured containers, or extreme cooling (like for rockets).
Hydrogen is flammable, but kerosene is not; kerosene is instead combustible. Here's the technical difference between the two[0], but in practical terms it means that you can drop a lit match or cigarette into a tank of kerosene and nothing will happen. You can even heat a tank of kerosene directly with a propane torch without igniting it[1].
[0] https://en.wikipedia.org/wiki/Combustibility_and_flammabilit...
The energy density per mass is very high, but it's also the least dense gas, so the volumetric energy density is absolute crap, even at high pressure. A bucket of kerosene contains a lot more hydrogen atoms than a bucket of liquid hydrogen, and unlike the hydrogen, it's safe to keep at room temperature, at normal pressure, and it's neither corrosive, flammable, or explosive.
The ICE engine with highest thermal efficiency reaches just 50%: The Wärtsilä-Sulzer RTA96-C turbocharged 2-stroke Diesel [1]
https://www.autosport.com/f1/news/131772/mercedes-engine-hit...
https://www.enginelabs.com/news/f1-tech-what-is-turbulent-je...
I know solar energy is advancing, what about if we put thin-film solar cells on the exterior of the body of the aircraft? That might allow greater distance travel without much additional weight. There is already solar powered aircraft that traveled around the globe called the solar one. It is experimental but still a good concept to look at.
Now instead of kerosene burning in a jet engine, "we are all fucked if it doesnt work", its burning in a simple compact, "fuck it if it doesnt work", generator.
There are a few nice things about this. One is, it decouples your power generation from your thrust generation. If the generator fails, you still have a perfectly usable engine for some time. You can declare an emergency and land at the closest airport (easy to do if you are GA in the US). Same goes for all fuel starvation scenarios, fuel contamination, fuel pump malfunctions (for aircraft that use those). If you are using a turbine as a generator, it can probably burn anything you'd classify as fuel. Electric engines will probably get away with longer periods between overhauls and are more reliable.
This will not be cheap though. It also introduces a high voltage, high power electrical bus where there was none before. And it is a more complex approach, with more things to go wrong, even if it may save in maintenance. For instance, take your average Cessna: you can lose your entire plane electrical system and your engine won't care. It has (redundant) magnetos which are coupled to the engine itself and will spark as long as the engine is rotating. Fuel is gravity-fed for the most part. So as long as your have fuel in your tanks (and throttle and mixture controls are in the right positions) the engine will run. Some of your critical instruments (like the artificial horizon) are mechanically powered (vacuum pump) so you can still use them without electric power.
If you lose your electrical system in a hybrid (or electric plane), or if you have to turn it off (fire?), this is now a engine-out situation. You are also going to lose your instruments.
Not much of a gain, unless we are talking about ridiculously large wings (think glider-sized and above).
Also electical engines can be throttled up and down with much better granularity. An idling jet engine still produces a lot of trust and burns a lot of fuel even before it leaves the ground. So the efficiencies you get from better control over the output are substantial as well.
Basically the current state of the art gives you a flight time of typically 1-1.5 hours with most electrical planes. If you double or triple that capacity through better batteries you basically get planes that can do short haul. The expectation is that that is basically happening over the next decade.
Electric engines are lighter than ICEs but batteries are very heavy and unlike jet fuel they don't shed their weight as they are used.
The second problem with battery-electric aviation is that most large aircraft aren't designed to land at their take-off weight. Landing gear typically comprises some of the heaviest materials on the airframe, so landing at a lighter weight than you take off at is a big advantage. This also manifests in the range of the vehicle. Burning fuel reduces the power needed to maintain lift, which give you additional range with your remaining fuel. By comparison, range with battery-powered aircraft would be linear.
The last hurdle is just the sheer energy density required. A 747 requires 50-60MW just to stay airborne at cruise, and will produce on the order of 250MW during take-off. Even a business jet produces ~10-15MW at max power, and will cruise at around 1.5-3MW. Over the course of a 10 hour flight, the lower bound is somewhere around 10-15MWh, which would be 37-56 metric tonnes of battery mass using the upper limit of current battery energy density (265Wh/kg). Keep in mind, it's not enough just to get to your destination, you also need a reserve while you're in the holding pattern, plus an additional safety factor.
There might be interesting new markets opening up in the personal air-taxi space, but I'm skeptical. Personally, I think the new wave of short-haul rooftop-hopping electric aircraft will prove to be a black hole money-pit, and a regulatory nightmare. The aerospace industry is littered with broken dreams.
I suppose people want to get there in a hurry, but a flight that goes from 30 min to 1hr or 1 hr to 2hr might not be too bad.
Customers are definitely willing to trade time for cheaper flight (Boeing made this gamble and won in the last airframe generation), but there are certain practicalities that need to be met.
Attach some batteries with wings to the aircraft that you release after you get up to altitude. These days you can put an autopilot on the batteries and fly them back to the airport for recharging. You'd save some weight once at altitude and could get a 'free' lift up to altitude. Sort of like how a sailplane can get a tow. Maybe you could take them up to 30-40k ft at a good speed and let them trade some height for speed along their path to the destination.
Clearly there is a cost for the added complexity, but it might be worth it given the cheap computation and improving autopilot software.
In the extreme, the most efficient place to fly is in the most cold and dry air. That occurs at the tropopause, which is generally between 35,000 and 50,000 feet (-60*C). You don't get to play around at that altitude without a large complex aircraft.
https://www.windows2universe.org/earth/Atmosphere/tropospher...
But couldn't you achieve the same effect by locating batteries in the wing? The point of the previous comment is that comparing fuel weight with battery weight is deceptive because electric engines are lighter. That doesn't mean an electric engine system is lighter weight than a conventional jet engine system. (So the structural design you're describing sounds feasible.)
I was pointing out that the reasoning was flawed. The engine is not the limiting factor in the design of the wing, and in fact can let you reduce the mass of the wing. An electric motor and airframe might be lighter than an engine and airframe depending on the design. However, you do need to compare the battery weight with the fuel weight, because the energy has to come from somewhere, and an airframe is designed with that reduction in weight in mind. It's hard to stress just how important energy density is for an aircraft.
The reason why the engines and fuel are in the wings has more to do with the center of gravity. This needs to be where the wings are for the plane to be stable because of the non trivial amounts of fuel that get burned and the weight of the engines. If you'd store this in the back or front of the plane, the plane would get progressively harder to control through the flight.
With batteries, this is a non issue. You can put them wherever as long as the center of gravity is in the right place. It won't shift as you deplete the batteries. But still, the wings are probably going to be a popular place for this.
Comparing with a long haul 747 is of course a bit unfair. It is worth noting that these planes are being replaced by more efficient two engine planes that are lighter and much more efficient. But I agree it will be a while before we see cross Atlantic flights at that scale. But we're talking short haul here; 1-2 hour flights.
A non-shifting static margin is certainly a benefit for electric aircraft, but we already successfully design aircraft that do have a shifting static margin. The interesting question is whether or not a constant mass would let you design airframes that would be impossible with fuel and ICE.
1-2 hours looks possible using current and near-future technology, but has anyone actually done a cost analysis on flying electric aircraft that are always at "full fuel" weight versus standard aircraft doing the same journey with half a tank? I can't imagine it's completely cut and dry, because the aerospace industry has had its eye on various forms of electric propulsion for decades.
Also, what's the turnaround on these things? Airlines want to make money, so they want to minimize the amount of time the aircraft spends on the ground. That's going to be a major hurdle, since even charging 2MWh over the course of an hour or so requires 2MW of power going into the vehicle. That's not an ungodly amount, but it's still non-trivial.
How do you make them much lighter? Lithium is a pretty light material.
Petrol is so energy dense because you are storing that energy in chemical bonds. Electrical energy is not as "dense". I think we are close to "optimal" batteries.
In terms of engineering development over medium term, that is not very much, so I'll bet this will happen.
how much safety is of a concern depends on application. for fully autonomous cargo planes you'd already reduce it significantly and can be improved further by routing them around and not above densely populated areas.
they'd be highly situational, but for those routes they could be approved for they'd be great.
Most of the weight and aerodynamic footprint of a plane is not fuel weight but airframe and contents. You seem to be implying that electric planes will have substantially different aerodynamic properties (high speed cruising at low altitude, no more takeoff expense, "gliding" at reasonable cruise speed)
Further, in terms of wasted weight batteries seem perhaps worse than fuel, because while you can fly a plane on shorter flights with tanks partially empty, it is much harder to reduce battery weight per flight.
For those short electric hops, how much of the total battery capacity required would already be used up at liftoff? Maybe catapults/winches/detachable power tethers could make a real difference here?
Wouldn't it add a ridiculous amount of weight compared to kerosene.
As to why: Kerosene isn't really an option any more. We have a climate problem, and in this generation, not some future generation.
And yet you need to keep at least that flight time as a minimum safe reserve.
However, we are not anywhere near close of achieving the performance of jet engine aircraft, be it speed or range. Passengers are not going to want to fly much slower than they are now.
> Most flights are much shorter than that meaning a lot of their weight and range is redundant
This is wrong. Most of the weight is fuel, which you can reduce by not topping off the tanks. In fact, airliners will do these calculations multiple times a day for every aircraft. On the other hand, you can not make a battery go lighter by charging it less.
> electrical planes don't need to get up that high and can cruise efficiently at both low and high altitudes
This is wrong. While they don't have to fiddle with the fuel mixture, they are still subject to air resistance. Unless you are flying slow, but then take out the Airbus from the discussion. And you can still fly slow at high altitudes with larger wings.
> So you pay a huge price for getting all that weight up on every take off.
That you do. But the weight actually * decreases * over time. Not so with a battery.
> nce cruising, operating them as a glider is actually feasible as well because you can safely turn the engines off and on again
Noone is going to book a flight on a glider to go anywhere except for leisure. As a part-time glider, you still want as much altitude as you can get (energy, in other words).
Even for GA it's a stretch. Many pilots (and the AOPA) recommend landing when you have less than one hour of fuel left. One hour is more than the entire range of most electrical aircraft in development.
I can see hybrid GA aircraft getting used (to save on maintenance), and maybe even electric trainers.
I am all for electric engines, but the challenges are not just "a few".
For short flights, a crossover between an airship and airplane might be an interesting idea. Economic and technical arguments might shoot it down but I'm just contemplating here.
If there was a balloon attached to the body of the plane that would provide most of the lift the electric motor could just drive the propellers or motor fans for mostly forward propulsion. The overall speed could be slower because the wings wouldn't have to convert airspeed to so much lift, saving energy. On short haul flights the speed wouldn't be a big problem.
The plane wouldn't thus rise up directly like airships: the balloon would only give most of the lift required for flight. Large but light wings would provide the remaining bit of lift starting from slow speeds and the plane could thus basically behave more like a normal plane, taking off and landing as usual albeit at significantly slower speeds, figuratively as if the plane was swimming in low gravity or, alternatively, 10x denser air.
A balloon would obviously introduce a lot of aerodynamic drag but since the balloon would only help in lifting the plane it could be a bit smaller. We could also build it into an aerodynamic shape instead of a traditional balloon, and we could integrate parts of the helium filled balloon onto the plane itself. For example, we could give the small plane huge biplane wings made out of light-weight steel mesh with helium-filled pods inside.
Edit: Similar idea in https://www.youtube.com/watch?time_continue=188&v=oxotOEZCh8... where 60% of the lift comes from the helium and 40% from aerodynamic forces.
I can't wait to take my first electric flight!
https://www.youtube.com/watch?v=Jcpq6XYYoY4
This is probably the closest thing we have right now and the foreseeable future.
if they would be really ecological and not hypocrites they would stop making money from oil resources
At some level every entity, person and organization is a hypocrite in some way or another. So instead of pointing fingers, we should celebrate wins when we can.
How do you get to that? Norway has extremely tight immigration policies. They hardly let anybody in. Their multi trillion dollar bounty will primarily benefit a few million people, while they export extreme per capita pollution; their per capita oil production is consistently among the top five or six globally.
What spectacular technological breakthroughs and exports has Norway produced from their oil riches (in clean energy or otherwise)? I'm not aware of any. Contrast them with neighboring Sweden for example when it comes to technological innovation. Norway isn't that type of culture, they're much more akin to the insular, small kingdom petro states of the Middle East. You don't have to take my word for it, you can look at their primary industries, their nobel production, their scientific output and their technology invention.
That's certainly what they appear to be doing with electric planes. This will spur innovation and lower prices.
Norway is in the EEA. If you're an EU/EEA/CH citizen, you're in. May be difficult for people not from Europe, but it's not closed off.
That is a myth (or propaganda). Norway immigration population stands at 16.8%. For example the US immigration population is under 15%.
Norway also went out of its way to avoid the very large immigration influx that eg Sweden allowed. They have a careful, rigid immigration approach (for obvious reasons, they'd be flooded instantly by immigration if they allowed it). Their immigration for 2017 was the lowest number for the last decade and it has been declining persistently since 2011. They're locking things down.
The US doesn't use a merit or equivalent based immigration system, as most developed countries do, including Norway and other nations such as Canada or Australia. That means if you are a low skill or low wage worker, you can actually get into the US. It's one of the few developed nations that allows such a thing.
Edit for trhway's comment below (I'm throttled on my replies):
I said nothing about absolute figures, I'm aware of the population difference between the two. One would naturally adjust what a 'large influx' means based on the population figures per country.
Show me the vast count of refugees that Norway took in versus Sweden. In just 4-5 years, Sweden took in 600,000 people, many of them from countries like Syria. While Sweden was doing that, Norway remained locked down by comparison (as did Finland).
Norway's very tight immigration policies would never allow that mass influx of refugees to happen. I don't necessarily blame them, they have an extraordinary situation for themselves. They're not interested in flooding their country with low wage / low skill persons that would dilute their very wealthy welfare state heavily through cost addition (without the off-setting tax base gain you get from skilled immigration). It's a cultural choice. Sweden is now seeing blow-back from the choices they made, in the rise of anti-immigration far right political parties there and a rejection of their former immigration policies.
Norway is one of the most desirable countries on earth to live. It has one of the highest standards of living. Its people are among the richest that have ever existed in history. You know why they aren't drowning in immigration? That's their tight immigration policies in action. Otherwise, it'd be a million people a year pouring in.
what are you talking about?! Have you tried to Google? Sweden has 2x population of Norway and 1.4M immigration population which makes it under 15%.
>Show me the vast count of refugees that Norway took in versus Sweden.
With regard to specifically refugees - both countries mostly have refugees from Middle East and Africa - Norway has 160K total refugee population, Sweden - 230K. Thus one can say that Sweden even less refugee friendly than Norway.
>In just 4-5 years, Sweden took in 600,000 people, many of them from countries like Syria. While Sweden was doing that, Norway remained locked down by comparison (as did Finland).
sorry, man, you just have to at least to google before posting.
That's just not true. I'm not skilled. I don't have a degree. I did happen to meet a Norwegian some years back and marry him. In addition, folks from the EU can come over and work. There is a strong immigrant workforce doing non-skilled work. Bartenders, janitors, factory work, and so on.
The US system has its downsides. The Norwegian system is pretty straighforward with what is expected of folks - or at least that has been my experience. The US has a lottery for some things, and the wait time for green cards is ridiculous. While some of the politicians in power aren't so immigrant happy (They recently increased the qualifacations for permanent residency and a bit on citizensip), at least the king promotes messages of inclusiveness. Trump, on the other hand, doesn't.
Norway is in the top ten in terms of the migration rate. https://en.wikipedia.org/wiki/List_of_countries_by_net_migra...
> their nobel production
In terms of Scientific Nobel prizes, Norway is in the 7th position, with a rate of 15 per 10 million compared to Sweden(rank 5) with 17 per 10 million. Not a big difference.
https://en.wikipedia.org/wiki/Nobel_laureates_per_capita#Sci...
Well, all the scandinavian countries are very innovative compared to their population, so that's not a very fair comparison.
Anyway, Norway is still extremely innovative. Maybe not in consumer facing and software related industries, which is what gets visibility in Hacker News. Norway doesn't have Spotify or IKEA.
But Norway has the worlds cleanest production of aluminum. It has been innovative in fertilizer production. It has a very strong microelectronics design industry. ARM's GPUs are designed here, most of the worlds Bluetooth Low Energy microcontrollers and other RF microcontrollers. It has the worlds leading automotive CMOS imaging sensor design center. Etc. Tomra is a world leader in recycling technology. And lets not forget all the non-petroleum marine innovation.
Yes, the oil industry is dominating. It's very difficult to get investments outside of petroleum (although that is improving as the desire to diversify is growing).
But seriously, Norway is doing about as well as can be expected of an oil producing nation. And if you think it's realistic to expect oil production to be cut on the supply side, you're hopelessly naive.
I'm an immigrant here in Norway. The immigration process has been pretty straightforward. Much better than the crap I read about the US system. I'll add that I'm american, and have had to go through the entire process.
Folks from the EU have it fairly easy - basically, so long as you have a job, you can stay. Simply tell the government you are here (there might be another step or two, but it is simple). Like a lot of places, you just have to go through the right channels and have a reason to be here.
A lot of the folks I know are immigrants as well, from different places in the world.
My understanding that Scandinavian countries are very expensive for every day living expenses.
(As a single healthy educated adult male, its too late to enjoy the free child care, education, health care, etc)
But they are expensive. A single bus ride (paid in cash) is as much or more as a latte. Norway is a bit more expensive - to the point there is a (free!) bus that goes between here (Trondheim) and just over the border in Sweden so people can shop cheaply. The amount I spend on groceries and a bit of spending money would more than pay rent and my food (but not all of utilities) in Indiana. I also eat well (mostly vegetarian save for some fish at least once a week). If you go far enough north, you get taxed less, though, to encourage people to live up north. I'm not sure living expenses are cheaper, though.
On the other hand, wages are different. You might make less as a programmer but more when working in retail. And I can definitely plan my expenses better.
I've used this tool in the past, and found it good to get a rough, general estimate: https://www.expatistan.com/cost-of-living/comparison/stockho...?
These institutions need fixing, but it never seems to be a priority and most definitely not in the current political climate. :o(
And you are correct, it isn't perfect, but I think those stories happen everywhere. I'm still happy to be dealing with these bureaucratic monsters as opposed to the american immigration monsters.
You are most definitely correct on the current political climate. If anything, they have made things more difficult for folks. Initial immigration hasn't been so bad, but they did increase the requirements for permanent residency so that I have to prove I'm self-supporting, work for 12 months, be in school for a year, (even though my spouse has to prove he makes enough to support me each year) or be here a long time - I think they said 8-10 years. Again, though, not impossible by any means. It just made me wait longer for citizenship.
A lot of Norwegian innovation is in areas you don't hear about, often marine, sub sea or aquaculture. You won't hear about a revolutionary new ship bow (for example X-Bow) on your regular news sites, or some niche underwater technology.
Other than that, there's tons of stuff happening with green tech. Wind.. Electrification of shipping and ferries, etc.
I'm betting you're exposed to Norwegian technology on a daily basis without realising. AVR (Atmel) came out of Norway. Nordic Semiconductor, Energy Micro, etc, etc. Your gadgets are full of tech originally designed in Norway.
https://www.fool.com/investing/2017/03/19/you-wont-believe-w...
Also, Norway's oil comes from the North Sea - which I'm not sure counts as "easy".
I think you underestimate how difficult is to change a country-wide economy. The huge challenges involved is what underpins the whole peak-oil movement [1] - irrespective of whether the theory is correct or not, the challenges posed by a big scale energy source transition are very well described.
Historical analysis tends to disagree with the underlying philosophy of peak oil.
People think of different things with peak oil. At the basic level production will peak - with a finite resource you can't keep increasing extraction for ever. On the other hand people sometimes link it to running out of oil which probably won't happen - instead we'll move to renewables because they will be cheaper and greener.