Airbus E-Fan Electric Aircraft Makes First Flight 160
An anonymous reader writes "The aviation industry has taken a tentative step toward electric power with the successful maiden flight of the Airbus E-Fan. The manufacturer known for the massive A380 jetliner began testing this small experimental aircraft last week, with the ultimate aim of lowering the huge carbon dioxide emissions from commercial flights. The E-FAN is powered by 120 lithium-polymer batteries, and can fly at speeds up to 136mph. Measuring just 19 feet from nose to tail, the compact aircraft show that Airbus probably isn't ready for commercial zero emissions flight just yet, but it does highlight the potential benefits."
Flight time 1 hour (Score:4, Informative)
For this version of the plane.
http://en.wikipedia.org/wiki/A... [wikipedia.org]
Re:Flight time 1 hour (Score:5, Informative)
Jet fuel has at least 50 times the energy density of lithium batteries [wikipedia.org], so even accounting for the low efficiency of jet engines, that hour looks about right.
Re:Flight time 1 hour (Score:5, Interesting)
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Its also very heavy and less efficient than pure diesel. The only reason its used in railway locomotives is that having an electrical connection to motors in the bogies (trucks to americans) its a LOT simpler and more reliable than mechanical linkages + gearboxes or compressor + hydraulic lines + hydraulic motors.
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Whilst you highlight some of the advantages of electric over diesel, I don't buy that that's the whole reason for diesel electric trains. I suggest the advantages include efficiency, just as with hybrid cars.
Why? Because the first diesel electric locomotives were shunters, and they don't power up the bogies or a train, they just push or pull. So your explanation wouldn't cover it.
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Whilst you highlight some of the advantages of electric over diesel, I don't buy that that's the whole reason for diesel electric trains. I suggest the advantages include efficiency, just as with hybrid cars.
Why? Because the first diesel electric locomotives were shunters, and they don't power up the bogies or a train, they just push or pull. So your explanation wouldn't cover it.
Boggies = trucks = wheels. Grandparent is talking about getting power from the engine to the wheels is simpler using diesel electric tech than a pure diesel tech. You still need to get power to the wheels of the locomotive when you're shunting. However with diesel electric you don't need a 1000HP clutch.
Interestingly I see things like this around for shunting (eg: at a processing plant), which are not diesel electric:
http://www.trackmobile.com/com... [trackmobile.com]
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Where did all the news about fuel cells go??
A few years ago they were on Slashdot every week.
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Fuel cells work, but they are vastly more expensive than batteries. Most people just got bored of waiting for a breakthrough that would make them cheap enough to be viable.
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Airships get their bouyancy for free. An aircraft has to drag its weight up into the sky using fuel so the last thing you want is a heavy engine with poor hp/ton ratio.
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I think you're being optimistic. Diesel might have better fuel economy per unit volume than petrol or avgas, but diesel fuel is somewhat denser and therefore heavier than both.
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Re:Flight time 1 hour (Score:4, Insightful)
we can do some fermi estimation. the article says that the plane has two engines with combined power of 60kW, and has a flight time of 45 min - 1 hr. if you fly for an hour at full power, that's 216 MJ. More likely the batteries are sized assuming the plane is on average running on just a fraction of full power. (waves hands->) let's say 130MJ battery capacity which is 1 gallon of fuel.
so the e-plane carries 1 gallon-equivalent of energy. Yes, energy density is the main challenge here!
Carbon neutral aviation biofuel ... (Score:4, Insightful)
Jet fuel has at least 50 times the energy density of lithium batteries ...
And various aircraft ranging from a Boeing 777 to a US Navy F/A-18 have been flown using aviation biofuel, carbon neutral. Its experimental an hellaciously expensive but its a more realistic future.
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There are other advantages to electric engines besides the pollution aspect.
For one, they're much quieter, which is one of the major problems with modern air transportation. The engines are also a lot simpler, reducing maintenance costs and risk of failure during flight.
Electricity is also a much more versatile form of energy than combustibles, since we know how to generate it from almost every other energy form.
Imagine a hybrid electric plane. You could charge it at the airport and take off on battery powe
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Again, that said, it is a really cool technology demonstration. I just don't see commercial viability.
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Indeed, aviation is the one rational use of biofuel.
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What's the cost of jet fuel vs the cost of a recharge? Aircraft are most inefficient in the take off/landing phase where there's a lot of speed adjustments, denser air and so on. This means that a big chunk of emissions comes from short hops e.g. London to Edinburgh, London to Paris - flights that only take an hour, or even less in some cases. Of course the law of diminishing returns bites you for long haul as you need substantially more fuel onboard.
Jet fuel will remain king for long haul, but if you co
Re:Flight time 1 hour (Score:5, Informative)
Jet fuel has at least 50 times the energy density of lithium batteries
But it is also converted to thrust at only about 30% efficiency [wikipedia.org], while the lithium batteries are over 90%. So that gives a ratio of about 15:1, not 50:1. Of course, that is still pretty bad.
Re:Flight time 1 hour (Score:4, Informative)
Not to mention that the aircraft doesn't have to carry consumed fuel, while it has to carry consumed batteries. And in some cases, aircrafts take off with near empty fuel tanks but with overweight loads and refuel once airborne.
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Great. Now all we need is a 5200'+ airstrip every 60 miles or so along flight corridors. I wonder how long it will take to get to Seattle then? Let's see, preflight, wait in line for ATC to give the go ahead to take off. . . at every stop, not to mention anywhere from 12 to 20 hours to recharge the cells. Multiply that by about 45. Hmm, I think I'll take a train instead. I'll get there days more quickly!
I think teleportation will be a reality by the time battery tech enables heavies to fly cross country.
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I think this makes total sense. If we see hydrogen fuel cells it may rather be airplanes before ground vehicles. The biggest problem with hydrogen in cars is not only the lack of a distribution network, but also the leakage. Leave the car parked for a month and it is empty. This would not happen with a plane, fill it up and "burn" it more or less immediately. The airport is already a place where specialized fuels are delivered and stored, hydrogen may not be so much an added hassle.
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Maybe 60 mile effective range ? (Score:3)
That's still a good amount of time to be useful for things like island hopping.
The article states endurance between 45 minutes and 1 hour. But lets be optimistic and assume 1 hour ...
... maybe a 60 mile one way (plane stays and has time for recharge) or 25 mile round trip (plane immediately returns)?
Not all that time is "available", at *least* 20 minutes should be reserved for safety. Lets subtract 5 minutes at each end for traffic patterns. So we're really looking at something closer to 30 minutes in practice.
Once you factor in taxiing, climb, descent, etc
Now if you are bei
Maybe as a curiousity or specialty rental (Score:2)
Range probably isn't a real issue as it is offered as a 'trainer'. But a trainer should be paying for itself and this will spend too much time on the charger for that.
But the flight school won't be impressed with 45 min flight and an hour (is that all?) on the ground to recharge. On good days (and this isn't a bad day plane) we turned around the small trainers in minutes for the next student. Unless this is half the price for half the flight time it's just another feel-good product that no one will actually
Battery swap (Score:2)
But a trainer should be paying for itself and this will spend too much time on the charger for that.
But the flight school won't be impressed with 45 min flight and an hour (is that all?) on the ground to recharge.
Non experimental-versions of this aircraft (such as potential trainer that you mention), could implement swappable batteries.
(As it's the case with Tesla Model S. The battery is designed to be swappable and Tesla is working around a "fresh battery rental" system).
In that case, the thing which is spending time on the charger is the spare battery pack, while the other pack is flying in the air craft.
Have 2 (or 3) sets of battery rotating, and you don't need to think about charging times.
The time schedule now
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The world's shortest scheduled commercial flight is just 47 seconds long, so there are some opportunities!
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Even daytime VFR flight rules in the US require 30 minutes of fuel beyond your expected destination. So the 45 minutes to 1 hour turns into 15-30 minutes of usable flight time. At 100mph cruise, and counting the extra fuel burn for climb, it probably has a 30 mile useful range.
BTW - why ducted fans? For low subsonic speeds, unducted props are more efficient, thats why they are used on virtually every low subsonic aircraft. (everything from a piper cub to a commercial twin-turboprop. There are some nice
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Ducted fans are quieter I believe. Some speculate that moving to them for light aircraft might help eliminate complaints about small airports, thus helping to ensure that small airports will continue to exist.
Of course, that won't help when the local CEO wants to be dropped off in his Gulfstream.
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And if Slashdot existed back in 1903, they would say that the Wright brothers flight wasn't long enough to be practical. Or they didn't go 175mph, so it's not fast enough.
I like the design. There are gliders that would work well as a platform. You could turn off the electric motors easily and just coast for a while to ride the air currents...
But this needs NASA's highway in the sky project to get it out to the normal pilots and future pilots if there are a lot of them.
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Except that there are chemical limits that put a real ceiling on the energy density of batteries
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Well, you could use a fuel cell to generate power, and that has the same energy density as whatever fuel it burns. Hydrogen energy density isn't great on a volume basis, but on a mass basis it is just fine (though the container it is stored in adds a lot of mass). For an aircraft I suspect the mass matters more than the volume, which is the opposite of how it is on a car.
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True- and large cryogenic tanks and associated filling equipment are probably more realistic on a large aircraft then on public automobiles.
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True- and large cryogenic tanks and associated filling equipment are probably more realistic on a large aircraft then on public automobiles.
I wasn't even thinking about cryogenic storage. That might make sense for large aircraft. The energy per unit mass of hydrogen is pretty high I think. If kept at atmospheric pressure the storage tanks don't have to be heavy. You'd have constant boil-off, but that is only an issue if you leave aircraft parked with fuel in them, which isn't really the case for large aircraft. For a car having to burn all your fuel within 8 hours of fueling is a big problem, but aircraft fill up before just about every fl
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You could turn off the electric motors easily and just coast for a while to ride the air currents...
...if you weren't loaded up with a giant pile of batteries, sure.
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And if Slashdot existed back in 1903, they would say that the Wright brothers flight wasn't long enough to be practical. Or they didn't go 175mph, so it's not fast enough.
No wireless. Less space than a horseless-carriage. Lame.
PRACTICAL zero emission aircraft (Score:2)
Great range, zero emissions, they've already been tested.
This is very doable.
http://en.wikipedia.org/wiki/N... [wikipedia.org]
And I don't see any potential downsides
How is that practical? (Score:3)
If it was so practical, why did they wholly cut funding. Seems like they had a long way to go to make the nuclear design feasible to where the crew was safe.
And how many civilians would fly with a nuclear reactor?
Replacing the nuclear reactor with batteries means A LOT of batteries. So I'm not sure how you can claim the whole idea is feasible just from a working nuclear design.
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just build the entire plane out of laptop batteries, lego style.
Re:How is that practical? (Score:5, Informative)
If it was so practical, why did they wholly cut funding. Seems like they had a long way to go to make the nuclear design feasible to where the crew was safe.
And how many civilians would fly with a nuclear reactor?
Replacing the nuclear reactor with batteries means A LOT of batteries. So I'm not sure how you can claim the whole idea is feasible just from a working nuclear design.
According to a Discovery Channel documentary:
1) There were two kinds of engine: Indirect Air Cycle that never got off the drawing board and Direct Air Cycle, that was actually built and tested but it emitted radioactive pollution and even back in the 50s and 60s people started to have second thoughts about a hundred or more things like this making regular operational flights spewing radioactive material over the countryside. http://en.wikipedia.org/wiki/A... [wikipedia.org]
2) What happens when one crashes? (see pollution concerns raised in point 1).
3) Shielding proved to be a problem. The aircraft power plant was only partially shielded because of weight constraints. The crew sat in "radiation shadows". and the power plant radiated in all other directions.
5) Combat aircraft have been known to have very high peace time attrition rates, a case in point being the F-104 at 30%. (see pollution concerns raised in point 1).
4) The thing would have been a logistical and maintenance nightmare.
5) ICBMs became a more capable and practically unstoppable delivery options. ICBMs were also likely to be a much safer weapons package during handling and in day to day peacetime operation.
6) Nuclear submarines became a viable option. Here weight was no issue so reactors could have full shielding and safety mechanisms. Subs were also way stealthier than any bomber so their combat survivability rating was higher and they carried a bigger war-load.
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Here [wikipedia.org] are some.
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Great range, zero emissions, they've already been tested.
This is very doable.
http://en.wikipedia.org/wiki/N... [wikipedia.org]
And I don't see any potential downsides
Did any of those tests actually conclude that they're viable? As I read the wiki, it seems the entire testing involved validating the shielding worked. Did the planes actually get powered by the nuclear engines?
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And I don't see any potential downsides
Except for the infeasiblity of shielding it, sure.
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The heat flux is proportional to the temp differential between the reactor coolant and the outside coolant. The former is typically around 600F, so another few dozen degrees on the outside coolant ain't hardly much of a difference.
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its the volume of air flowing over the aircraft
No, not volume, mass. And water is 800 times as dense as air.
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E-plane on a treadmill? (Score:5, Funny)
The aft main wheel includes an electric motor with 6kW power, which provides taxiing and acceleration up to 60km/h during the take-off
This may give the "plane on a treadmill" problem a bit more traction.
NOT zero-emissions! (Score:2, Flamebait)
Electric vehicles are not (necessarily) zero emission - you need to consider where the electricity used to charge the batteries comes from.
All from wind and hydro? Not bad (depends on how much fossil fuel went into the construction of that wind and hydro, so not necessarily zero emission but close). All from the coal plant? Ermmm...not so much.
Re:NOT zero-emissions! (Score:4, Insightful)
YES zero-emissions! The vehicle emits no carbon dioxide.
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The fossil fuel based generation plants that send energy to the grid and charge the plane do emit carbon dioxide. Therefore by charging the aircraft carbon dioxide is emitted. Therefore using the plane causes carbon dioxide to be emitted. The plane is not "zero emission" but "lower emission" in another place.
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But an electric vehicle can be zero emission dependent upon the source of the electric power. The common vernacular "zero emission" refers to the fact that no emissions are coming out of the vehicle while it is in operations. The emissions are decoupled from the vehicle and fall back to the power generation.
If we are going to be this pedantic about it, even an electric vehicle that gets it's power from a solar or hydro plant is not zero emissions because somewhere along the supply chain materials, process
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According to this [wikipedia.org] about 10% of electricity in France is produced from fossil fuels. So even in France it is not zero emission.
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But but but but ... the PILOT does! Which leads us to the conclusion ...
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Not this stupid argument again... It is getting old, and it proves your intelligence that you keep repeating it.
How much pollution went into making that gallon of fuel? A lot more that never gets accounted for. How about the security of that fuel supply?
Re:NOT zero-emissions! (Score:4, Informative)
It is getting old, and it proves your intelligence that you keep repeating it.
It keeps getting repeated because people keep misusing the term "zero emission". When you use an absolute term such as "zero emission" it is either true or false. In this case "zero emission" is false. All electricity from the grid, which is where these aircraft will probably be charged from, has some component of fossil fuel based generation. Therefore by using grid power the aircraft is causing emission; just on another location.
How much pollution went into making that gallon of fuel?
No one claimed fossil fuels were zero emission.
What the poster is trying to get at is to use a more accurate term such as "low emission" which is a true statement.
Re:NOT zero-emissions! (Score:4, Insightful)
The vehicle itself is zero emission. The cost, environmentally and otherwise, of fuel and production, while important, are separate issues that need to be addressed separately.
If you try to solve a large, complex, problem in toto, you will likely fail. Breaking it up into manageable pieces is much more likely to succeed, such as starting with the end user product where you get the most bang for the buck and then work up the chain. Transportation is the biggest problem which will take the longest time to effect a transition, so getting started on it is important.
Once you have the transition to electric vehicles underway, then you can work on the dirtiest of the electric supplies and every time you make the supply cleaner, you automatically make everything powered by that supply cleaner, magnifying the effect of that effort.
Trying to claim a zero emission vehicle isn't zero emission is just trying to confuse issues and holds back progress.
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If you try to solve a large, complex, problem in toto, you will likely fail.
By claiming zero emissions you claim to have solved the complex problem when it is far from the truth. By claiming low emissions you admit the fact that work still needs to be done.
Trying to claim a zero emission vehicle isn't zero emission is just trying to confuse issues and holds back progress.
Trying to claim zero emission when there are emissions confuses issues by claiming victory when victory has yet to be won. It also holds back progress. Why spend money on a fight when it is already won. By sweeping the fact that electric vehicles cause emission under the rug you hide the problem. How about the truth by admitting
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No, it is very specifically claiming to solve one part of the much larger complex problem.
Would moving all coal fired plants in the US to Canada solve the problem of US coal fired plane emissions? No it would not. It would just move the problem to Canada. The same thing is true for electric vehicles. It just moves the emissions from the tail pipe to the electricity generation plant but does not solve the problem. By "solving" a problem in one part of the system we are increasing a similar problem in another part if the system. Over all the problem is smaller but there is still work needed to be
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Zero emission vehicles don't release any emissions form the vehicle itself, which is a worthwhile improvement because vehicles tend to be operated where people live. Moving the emissions to a central location, away from populations and where they are much easier to capture and clean up is a good thing.
While we won't be seeing all electric zero emission passenger aircraft any time soon, it would be very feasible to create a hybrid aircraft that reduced emissions and noise around the airport itself and was ch
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Zero emission vehicles don't release any emissions form the vehicle itself, which is a worthwhile improvement because vehicles tend to be operated where people live.
While the location of pollution is an important factor that is not what people usually associate with the term "zero emission". In most people's mind "zero emission" is a short form for "zero emission of greenhouse gasses and therefore does not promote global warming". When most people drive "zero emission" vehicles they think "My car is not emitting greenhouse gasses so I am not contributing to global warming by driving it". That is not true. While electric vehicles cause less greenhouse gasses to be emitt
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It keeps getting repeated because people keep misusing the term "zero emission". When you use an absolute term such as "zero emission" it is either true or false. In this case "zero emission" is false. All electricity from the grid, which is where these aircraft will probably be charged from, has some component of fossil fuel based generation. Therefore by using grid power the aircraft is causing emission; just on another location.
You are trying to hold the term to an absurd and impossible standard. By this standard you will find that in fact no human activity can ever be zero emission because if there is just one single human involved in the activity then that human breathes oxygen in and CO2 out, and this is not zero emission.
The term "zero emission" was not invented just so that it could never be used and so a much more reasonable interpretation of the term "zero emission vehicle" is that the vehicle itself doesn't emit CO2 in ope
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By this standard you will find that in fact no human activity can ever be zero emission
Thank you for putting words in my mouth. That is not the standard I am talking about. If you want specifics, I use the following test;
"Is there CO2 created in generating the energy used to move the vehicle? "
If, at some time, all the electricity we used was created without burning fossils I would consider electric vehicles to be zero emission. That is not the case right now therefore electric vehicles are not zero emissions. Would you call a vehicle that runs on a flywheel zero emission if it used a gasolin
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"Is there CO2 created in generating the energy used to move the vehicle? "
This is not a property of the vehicle, it is a property of the power plant. There definitely are electric vehicles that get their electricity from emission free sources such as wind, solar, hydro or nuclear. Norway, for one, is full of them.
There could be power plants that produce electricity from burning little babies for all I know and if there are then this does not reflect negatively on the vehicle that ends up using that power because it doesn't really have much choice: once an electron enters the grid
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does not reflect negatively on the vehicle that ends up using that power because it doesn't really have much choice:
The driver of the vehicle does have a choice; to drive or not to drive. The choice to drive causes the power plants that generate the electricity to power the vehicle to emit CO2. Therefore the choice to drive causes CO2 emission.
Driving an electric car causes emissions of CO2. The only different in that they are less and at a different time and a different place that with an internal combustion engine. The point is that electric vehicles are not zero emission they are lower emission. They are only zero emi
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The driver of the vehicle does have a choice; to drive or not to drive.
The choice between having a life and not having a life, is no choice at all.
The choice to drive causes the power plants that generate the electricity to power the vehicle to emit CO2.
Only if those power plants actually do produce CO2, which is often not the case. Your assumption that all power generation always emits CO2 is over one hundred years out of date.
That is a marketing ploy as it does not decrease that actual emissions. It only causes people who don't buy certificates to use a higher proportion of dirty energy. It makes the buyer feel good but has no effect on the environment.
You are mistaken. Europe has a cap on total CO2 emissions in electricity generation, but no cap on total CO2 emissions from vehicles. It follows that every fossil burning car that is replaced by an electric one reduces CO2 emissions from the vehicle pool, an
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Only if those power plants actually do produce CO2, which is often not the case. Your assumption that all power generation always emits CO2 is over one hundred years out of date.
In every country of the world at least some of the electricity is produced from fossil fuels. If you want to say "zero emission" and not "low emission" then all the electricity has to be produced from non-fossil fuel sources.
Europe has a cap on total CO2 emissions in electricity generation,
You just changed the subject. First you were talking about green electricity certificates and now CO2 caps. They are different matters. Someone buying a green certificate does not decrease CO2 production because it does not change how the energy used is produces. All it does is allow th
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In every country of the world at least some of the electricity is produced from fossil fuels. If you want to say "zero emission" and not "low emission" then all the electricity has to be produced from non-fossil fuel sources.
Again you are demanding an absurd and impossible standard. However green your national power grid is, there is always going to someone somewhere using a diesel generator for something or other. This cannot be the yardstick used for moving towards a greener economy because all progress would be impossible.
Someone buying a green certificate does not decrease CO2 production because it does not change how the energy used is produces. All it does is allow the buyer the smug idea that they are using clean energy while someone else who does note buy the certificates is using more unclean energy. CO2 caps are different in that they require a limit in the production of CO2. The deciding factor is that at the CO2 cap is not zero. Therefore anything that uses electricity is not zero emission.
It remains a fact that anyone exchanging their gas guzzler for an electric vehicle is causing a reduction in CO2 emissions equal to what the gas guzzler used to produce. Simple arithmetic then reveals that
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Again you are demanding an absurd and impossible standard. However green your national power grid is, there is always going to someone somewhere using a diesel generator for something or other.
Those diesel generators will not be feeding power to the grid so that statement is irrelevant.
This cannot be the yardstick used for moving towards a greener economy because all progress would be impossible.
Falsely calling something zero emission stops progress because if falsely states that the goal is already met.
It remains a fact that anyone exchanging their gas guzzler for an electric vehicle is causing a reduction in CO2 emissions equal to what the gas guzzler used to produce.
This is a factually false statement. You miss the CO2 produced by the electricity plants to produce the electricity to charge the vehicle.
You could have picked a better analogy
Would a processed food be organic if no pesticides were used during the processing of the food?
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Those diesel generators will not be feeding power to the grid so that statement is irrelevant.
They very well might, you cannot know that they will not.
Falsely calling something zero emission stops progress because if falsely states that the goal is already met.
Which indeed it is for the vehicles themselves. Now it's time to start working on the power grid.
This is a factually false statement. You miss the CO2 produced by the electricity plants to produce the electricity to charge the vehicle.
No you are mistaken, European CO2 caps on electricity generation guarantee that the switch from gas guzzler to EV will cut CO2 emissions to zero for your car use. If you are in Europe, of course.
Would a processed food be organic if no pesticides were used during the processing of the food?
Meh, "organic" foods is modern voodoo, not interested in the debate.
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All from the coal plant? Ermmm...not so much.
I get your point, but even with fossil fuels it is often better to use a battery. The little engine on a plane tends to be inefficient compared to a massive power plant, and has fewer practical options for emissions controls. A power point is a concentrated emissions point and investments can be made to make it more efficient and to control emissions. Efficiency improves CO2 output, and emissions controls helps get rid of everything else.
So, even with coal power you're still better off getting things ont
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Yes RichO, what you say is correct, and tying our vehicle infrastructure to the electrical grid is a necessary first step, irregardless of how the power transmitted is produced.
I just worry that there are a lot of smug hipsters driving electric vehicles that think everything is fine, not realizing that perhaps 90%
of the electrons in their battery ca
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Electric Vehicles are NOT ZERO EMISSIONS (Score:2)
Can we please stop trying to insinuate that electric vehicles do not have a carbon footprint?
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Never! We will keep it up until every one re-buys everything they already own, THEN it will come out that they not only have a carbon foot print but it's bigger than that of the new hemp powered hot air balloons!
Re:Electric Vehicles are NOT ZERO EMISSIONS (Score:4, Insightful)
"but it does highlight the potential benefits" (Score:2)
It's as beneficial as sailing on top of a rock. No carbon footprint there either!
Add solar to extend range? (Score:3)
I have no idea if this would help, but with developments in solar technology, would it make a significant difference if the tops of the wings, fuselage, tail and fan ducts were all solar panels? Seems like a simple thing to do to help with range... maybe not done because it's not reliable.
This technology has no future (Score:2)
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" lowering the huge carbon dioxide emissions from commercial flight" - Until the energy density of batteries goes up and and we have an efficient, carbon dioxide free way to charge them, I'm not sure I see the value here.
Exactly. I don't see why they bothered in the first place. They should quit. Now.
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in my area, which has the busiest airport in the world some years (other LAX takes the title), we get 55 percent of our power from nuclear energy
4th gen reactors use nuclear waste as fuel ... (Score:3)
So which is worse - carbon footprint or trying to dispose of nuclear waste. Either way, there is no such thing as a zero-emission engine. Somewhere there is something that is creating waste products that have to be dealt with.
4th generation nuclear reactors will use the waste of previous generation reactors as fuel. So dealing with current waste is storing it for 30 years until the 4th gen reactors arrive commercially (research reactors are already running) and can burn it up as fuel. The waste from the 4th gen is far less dangerous and only remains hazardous for a few hundred years rather than tens of thousands.
3rd gen reactors are starting commercial construction and while they don't have the waste/fuel benefits of 4th gen
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carbon footprint is worse.
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Using electric vehicles (planes, trains or automobiles) is not just about shifting the CO2 emission point.
It allows use of energy sources that would not otherwise be viable for transportation (liquid hydrocarbons have a significant premium over other forms such as gas or solids). In addition land based power facilities have significantly higher efficiencies (open cycle gas turbines are lucky to get 40% efficiency, stick a waste heat recovery boiler on the back end and it is up to 60% efficiency).
The other a
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Until the energy density of batteries goes up and and we have an efficient, carbon dioxide free way to charge them, I'm not sure I see the value here.
Sort-of agree, and energy density is definitely a problem with batteries in any application. However, batteries make a LOT of sense when it comes to a carbon-neutral way to charge them. With a conventional engine you're almost always limited to fossil fuels. With a battery you could still end up burning coal to charge, but you've decoupled the ultimate power source from the plane so you don't HAVE to use fossil fuels. The battery could be charged by nuclear, even though you could never put a reactor on
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Solid-oxide fuel cells are a much more efficient way to burn hydrocarbons then conventional combustion engines. An electric airliner that used solid-oxide fuel cells could potentially get more range for the same weight of fuel - and unlike with batteries, you're not trading off fuel mass.
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Solid-oxide fuel cells are a much more efficient way to burn hydrocarbons then conventional combustion engines. An electric airliner that used solid-oxide fuel cells could potentially get more range for the same weight of fuel - and unlike with batteries, you're not trading off fuel mass.
Have they managed to extend the lifetime of fuel cells that work on anything other than hydrogen? That has always been the problem with burning hydrocarbons in fuel cells.
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No idea - but the general point was that pure electric air propulsion is a technology that doesn't exist in a vacuum. There's lots of ways it could become viable.
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Agree. Fuel cells actually make a lot of sense in any kind of transportation situation. They're far more effective than batteries at storing power. They're just not all that practical yet. As far as I'm aware the only fuel cell that REALLY works reliably is the hydrogen-oxygen fuel cell.
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The electric motor really doesn't change the difficulty of flying. In a small training aircraft, engine management is a very minor part of the workload.
Bonus points for resembling an A-10 ... (Score:2)
With only 45 minutes to one hour of flight time I don't see how this is considered viable or even safe.
Well if you consider it a technology demonstrator its pretty impressive, and that is all it is claimed to be. Plus it gets bonus points for resembling an A-10, see pictures from front.
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Yeah, if you just replace the back seat occupant with an equivalent mass of batteries, you could get twice the range.