Global Warming: Electric/Hydrogen airplanes feasable? [Archive]

Charbax

25th Sep 2006, 23:39

Hi, I am a big fan of cheap airlines in Europe, I use Ryanair, Easyjet and Sterling a lot.

Specially the last few years, I have been able to travel around europe to film festivals, between my mother in Denmark and my father in Switzerland, I have also been able to go to several computer tradeshows, also in the USA, which I made video-blogs from at http://video-blog.eu

But I am afraid of rising oil prices, and global warming. I feel kind of bad of the pollution that the airplane does, and oil not being a renuable energy source, I wonder if there is a chance some airlines soon switch over to some renuable energy technology.

I wonder if it would be feasable to fly the same sized airplanes, even some A380s, using a different, renuable and non-polluting source of energy. Would a big electric engine with big batteries be enough? Has hydrogen been tried?

chornedsnorkack

26th Sep 2006, 08:20

But I am afraid of rising oil prices, and global warming. I feel kind of bad of the pollution that the airplane does, and oil not being a renuable energy source, I wonder if there is a chance some airlines soon switch over to some renuable energy technology.
I wonder if it would be feasable to fly the same sized airplanes, even some A380s, using a different, renuable and non-polluting source of energy. Would a big electric engine with big batteries be enough? Has hydrogen been tried?

Batteries aren´t good.

A big problem with airplanes is that in order to get off the ground in the first place, they have to have a large ratio of power to weight, and in order to fly any reasonable range, they have to have a large ratio of energy to weight.

Generally, a battery weighs more than oil that gives the same amount of energy. Boeing recently fley a man on a battery-powered plane, but I do not think very far.

And electricity has to be produced somehow. For example, from oil.

Hydrogen is more sensible. The problems are, for one thing hydrogen is cold. For another, it has very low density. A given weight of hydrogen gives much more energy than the same weight of oil - but a given volume of hydrogen gives much less energy than the same volume of oil.

Which is why A-380 sized and bigger airplanes are excellent for hydrogen power. A lot of space for the lightweight hydrogen fuel, and you do not need so much heat insulation.

Charbax

26th Sep 2006, 11:55

chornedsnorkack

26th Sep 2006, 15:00

Allright! So Hydrogen would be feasable? That's great news..
Does anyone know of test flights using hydrogen? Aren't Airbus and Boeing testing that?
So how long time until Ryanair, Easyjet and Sterling switches over to hydrogen?
Not soon. Hydrogen has a lot of technical challenges.
What is an advantage of hydrogen is that the large amount of energy per unit mass allows longer range with hydrogen. Provided that the airframe is built for this!

Gaspasser

26th Sep 2006, 15:30

The technical issues of running future designs of turbine engines on hydrogen could probably be overcome quite easily by redesign of burners and combustion cans.
The real problem is the logistics of making hydrogen refuelling available at key airports, and to be able to do this safely.
There is also the issue of legacy equipement that will continue to use jet fuel.
I guess to be realistic jet fuel will be around for the next thirty years its just whether it is produced from alternative sources than crude oil such as biomass, gas to liquid technology etc.

Charbax

26th Sep 2006, 16:01

Nice, so.. could ethanol be used to fuel airplanes without needing to tweak the current engines very much? And would that provide a solution for the pollution problem?

chornedsnorkack

26th Sep 2006, 16:11

The technical issues of running future designs of turbine engines on hydrogen could probably be overcome quite easily by redesign of burners and combustion cans.

If you do, you also have to put in place insulation for the fuel talks. What you get is a plane with short range that is overweight in very many places.

What you need to do is design the whole airframe around the density requirements of hydrogen.

Rainboe

26th Sep 2006, 17:54

I should stop listening to all this propaganda! Global warming is not our fault. The world is never stable- it is always cooling down or heating up. But it is long term stable- otherwise life would never have got this far. Europe will go through another Ice Age after a bit of warming up. The sum total of human pollution compared to a really big volcano isn't worth bothering with- there haven't been any damn good volcanos lately, so don't worry about it. There is plenty of oil, more is being discovered and more efficient ways of extracting oil from shale developed. What is the problem? Oil is expensive for political reasons. As oil gets more expensive, other power sources will be developed. Meanwhile, that seat of yours on the aeroplane will be going anyway. Without your ass in it, what a waste of resources! So travel and enjoy it and don't feel guilty. Sometimes these 'green' organisations are more 'political' than 'green'. They don't want any progress, they want us to live in villages and wear sacking for clothing while we farm our one cow and chickens, and only buy food that is grown locally. I like mangoes and strawberries (in the winter), and vegetables from Kenya (it actually gives the growers money). I don't know why so many people listen to this 'green' nonsense- the world will restore itself and then go the other way, then swing back again. All we shoud worry about is not polluting with poisons- PCBs and other chemicals (like womens, birth pills in the water supply). So fly and enjoy it- I do. And take your holidays wherever you like- have you seen the bikinis in Brazil?`

tribekey

26th Sep 2006, 20:17

rainboe-utter rubbish. The link between the amount of co2 in the atmosphere and the average temperature of the Earth is beyond doubt,it's not even difficult science, co2 reflects infra-red radiation back to earth, as does water vapour, methane etc. Given that the levels of co2 in the atmosphere have, beyond doubt been increased by man's activities then we do have a problem. Granted, no-one can say categorically exactly which parts of the planet may (or may not )suffer, but that's hardly the point is it? Surely,we can't afford to wait and see,gamble as it were?
Yes, there are natural cycles of warming and cooling, usually over thousands of years,probably linked to various factors(levels of radiation from the sun vary,for example) but it doesn't seem wise to add our own into the mix!
oh, and like it or not ,oil will soon be a diminishing resource,fact.Watch for 'peak oil' over thenext few years,we don't have to run out of the stuff to have a problem,when demand exceeds supply then just watch the world's economy wobble, that will be the thing that cuts down on expanding aviation.

Rainboe

27th Sep 2006, 11:13

Well, thank you, Sir, for the verdict of 'utter rubbish'! I find all this 'green' spin total nonsense! I do not think driving us out of our cars into filthy polluted trains/buses is going to make one iota difference! Not being able to travel will change nothing. This 'peak oil' nonsense will come to nothing- we were repeatedly told we would be running out of oil at the turn of the Century- the price is actually falling fast now. Sticking up all these awful wind turbines and killing all those birds with them won't help. We can expect efficient nuclear power, they are just discovering all the coal reserves we have quietly been ignoring for years. Watch my lips....'there is NO energy crisis'. The world previously had far, far more carbon dioxide in the atmosphere than it has now. The carbon dioxide down to us is irrelevant- it goes up and down all the time, and ultimately the world has a restoring element to keep things under control. Once the world was all volcanos and lava and very hot. It's managed to become the balmy place we all know and love now. Life adapts to climate change- maybe one day we'll all grow hair again. Instead of attacking and blaming ourselves for everything and demanding I stop eating Kenyan runner beans and Spanish strawberries, these 'green' organisations should stop the natives cutting down trees and poisoning us with insecticides. But FOE and Greenpeace just like attacking anything we do for political ends.

seacue

27th Sep 2006, 11:33

I've long been convinced that the last drop of the Earth's liquid fuel will power an aircraft.

Alternatives would seem to fit stationary uses and ground transportation much more easily.

But the "renewable" energy sources often use non-renewable energy today.

Dams must take decades to pay back the energy cost of their construction - and there is often a significant local climatic effect.

Wind and sun power require energy to create the installations and aren't "24/7" reliable..

Batteries require energy to mine and process the components and the components aren't "nice" in many cases.

Biofuels must be grown which takes fertilizer, today coming from non-renewable sources.

Simple answers to difficult problems are usually wrong. (I wish I could remember the actual quatation.)

The SSK

27th Sep 2006, 11:39

Rainboe, you can rant all you like but you’ve lost the plot. Look at what’s happening in the airlines – BA, Air France Virgin, they aren’t fighting environmental regulation, they’re trying to manage it. Look at what’s happening in the organisations – IATA, AEA, ICAO, ACI, ASD, Eurocontrol – the talk is of little else.
Your arguments are food and drink to the radical greens, they merely point and say ‘look – the airline industry’s in denial again’.
The fact is, it doesn’t matter what the truth is – the politics and the perception have moved on, and there’s no putting the clock back.
There are far more aviation professionals in Europe who are actively working to find solutions to this dilemma than there are those who deny that it is a dilemma in the first place.
As for the original question, forget hydrogen. Even if it were technically feasible, it would just replace CO2 emissions with more-damaging water vapour.

TSR22

28th Sep 2006, 20:55

First of all, Hi Guys!
I am as guilty as the rest of you :E for tootling around and polluting our upper atmosphere but I have to say, I am one of those people that would really like to see a green solution to our problems. Trouble is, even if we did manage to find a workable solution such as hydrogen/electric cells (very unlikely - how on earth would they provide the necessary range/power/thrust?) - we often only end up shifting the burden to another source. Hydrogen requires energy to produce it - this will probably come from a non renewable source - fossil fuel.
Rainboe - with the greatest of respect, denial is a dangerous activity:= . When the planet has cycled its atmosphere and climate, it took (in most cases - not all), thousands or millions of years. We have seen the largest and fastest changes in pollutant levels caused by human activity and it is unlikely that in the short term (within the lifespans of possibly hundreds of generations) the planet would be able to respond. Sitting down and doing nothing is not an option, because if we do - we will be sitting in some very deep water in the next couple of decades. The changes that are happening now are profound and will be long lasting and far reaching. Lets hope that a solution can be found, and fast. Three cheers for Mr Branson:D

barit1

28th Sep 2006, 22:21

The technical issues of running future designs of turbine engines on hydrogen could probably be overcome quite easily by redesign of burners and combustion cans...

I believe current engines would NOT require internal changes at all - H2 combustion would take place in a small fraction of the volume of present burners. (Future improved engines could have shorter combustors, shorter shafting between turbines & compressors, and thus lighter overall)

The big change would be in plumbing, pumping, metering, and fuel nozzles, to handle a MUCH larger volumetric flow of cryogenic fuel.

And of course there's the elephant in the room - the HUGE tankage required. Most of the fuselage volume would be necessary for a cryogenic tank for very low-density liquid H2.

Load Toad

29th Sep 2006, 01:33

OK - how are we going to make all this hydrogen we need?

Rainboe

29th Sep 2006, 11:58

Well folks, I am not 'in denial'. But I just don't believe all the doomsayers and lies put out by 'green' organisations. There are a lot of very dodgy statements of 'truth' put out by people. One of them is here:
"We have seen the largest and fastest changes in pollutant levels caused by human activity and it is unlikely that in the short term (within the lifespans of possibly hundreds of generations) the planet would be able to respond." I would say 'show me proof!' They are trying to scare us all by saying the atmosphere will be unsustainable- well after several billion years of torture, it's managed to sustain life quite happily. Drastic forecasts of running out of oil have been made for years- we're doing quite nicely thankyou with plenty all over the world, and more still be discovered, and a lot of previously uneconomic supplies becoming viable for processing. The melting of the glaciers....they naturally come and go. One day Europe will be under 2 miles of glaciers again...guess what- it won't be our fault! It's a natural process. All we need to do is plant lots of trees and cut down on the chemicals. The 'greens' can fret about peak oil and nuclear technology all they like- it really won't make much difference because these crises are still a lot further away than they think. So if you don't travel by air because you are worried about pollution, then it's a false argument because in practice you will be shifting the pollution to other forms....unless you walk!

chornedsnorkack

29th Sep 2006, 12:44

I believe current engines would NOT require internal changes at all - H2 combustion would take place in a small fraction of the volume of present burners. (Future improved engines could have shorter combustors, shorter shafting between turbines & compressors, and thus lighter overall)
The big change would be in plumbing, pumping, metering, and fuel nozzles, to handle a MUCH larger volumetric flow of cryogenic fuel.
And of course there's the elephant in the room - the HUGE tankage required. Most of the fuselage volume would be necessary for a cryogenic tank for very low-density liquid H2.
Or else you can make the wing bigger, and lighter.

But wouldn´t hydrogen burning generate higher maximum temperatures?

TSR22

30th Sep 2006, 09:08

Hi Rainboe!

I knew you would ask for proof! A government document was released about 2 weeks ago indicating that the pollutant (CO2) levels have risen drastically in the last decade (showing an almost exponential rise) - unfortunately, I cant put my hand on the document right now..:E
I know that there are a lot of men (and some girls!) with beards, sandals and little bits of spittle in the corner of their mouths who proclaim doom, but there IS a lot of compelling evidence published every month in respectable journals such as Nature or New Scientist (the latter being a bit more popular but less "hard" science). I tend to read a lot of these things (mainly because the medical stuff is so boring that I normally have to read!) and then discard the articles so I can't quote anything directly. There have, however, been some very hard hitting documents published recently and the governments of the world have started to sit up and listen. Jut look at the weather changes that we are seeing.. (I know that there is natural variation in this anyway - just observe the difference in winter temperatures from those of the 1940s).
I think that one of the other major problems is that CO2 and other pollutants such as lead tetra-ethyl, chloroflourocarbons etc are often long lasting and will continue to cause huge problems for hundreds of years to come. One fact I do have, is that if the Great Western ice sheet collapses, then the world sea level will rise in the order of 4.3 metres..(I got that from a "popular science" book but it is well researched and worth reading: "A short history of nearly everything by Bill Bryson - it's quite funny too in places!:8 )
I'm not a green campaigner by any stretch of the imagination but I am quite concerned about the long term future of life as we know it. I do like walking though!!;)
I looked at your profile - 747s eh! Only in my wildest dreams (and if the money doesn't run out!!!!):cool:

barit1

30th Sep 2006, 13:41

...But wouldn´t hydrogen burning generate higher maximum temperatures?

Yes, the peak temperature within the burner would be higher, but it would be diluted down to normal turbine entry temperature by cooling airflows in the aft part of the burner.

haughtney1

30th Sep 2006, 16:56

I'm of the opinion that there WILL come a time when a hybrid, or even completely new propulsion (hydrogen powered perhaps) for aircraft will come to fruition. Is that day coming anytime within the next 15-20 years? No... Why not? because the current technology still has a theorectical 30-40% left worth of improvement in it..thats why.

As for aviations impact on the environment, it depends on who you talk to, perhaps more telling is the overall 2-3% of global C02 emissions that aviation currently produces. Opinion is divided on the basis that no one has put in detailed research (despite what the local green loonies/soothsayer's/fundamentalists spout from there carbon emitting bodies) as to the effect of high altitude carbon emissions (again there are plenty of popular theories about..but very little real data) the jury is still out. Aviation as an industry has recognised that politically it has to move with the times..which it will continue to do.

Aviation is an easy, highly visible, and high profile target for the green lobby. Given this, it is perhaps surprising (and telling) that more effort isn't concerntrated in the area of the average western household, where with a few simple steps, the overall carbon footprint can be reduced by around 40%, which would equate to an overall reduction in emissions worldwide of 25% or so:ok: (or 8 TIMES the emissions of the aviation sector)

dudduddud

2nd Oct 2006, 06:25

but i believe that the leaders of the green movement are simply looking out for themselves. The more support they get for their loony, baseless arguments the more they get paid. simple.
They pay scientists to come up with this bullsht, which is almost always a best guess. If i was them, i would be disappointed in the fact they (the scientists) havnt managed to come up with a king-hit.
I knew you would ask for proof!
excellent lets hear it...
unfortunately, I cant put my hand on the document right now
thats a shame
discard the articles so I can't quote anything directly
oh and again
you see... theyre not worth keeping or quoting because theyre the sort of typical vague inconclusive (when you come down to the nitty gritty) green-a**-licking crap you would find in
popular but less "hard" science
magazines
unless of course youre quoting from a short history of nearly everything which has really got to be the last straw.
The thing i find really amusing about the green movement is how short-sighted it is. as the writer above me mentioned, they decide to go after the 2% polluter because they are an easy, high-profile target who are probably not much liked by potential green supporters anyway but neglect the 25% used by the average western household. the acronym
NIMBY
comes to mind. can you imagine how much support the green party would get if they advocated cold showers after a certain hour of the day, a limit to the number of kilometers you can drive with only one person in your car or a limit on the number of lights you can have switched on in your house at one time? noone would buy it, membership would decline, representation in parliment and the big salaries would reduce. these people arent volunteers remember.
FURTHER - The oil consumption/alternative paradox
Researching and developing alternatives to fossil fuel costs money. If one could say that the rate of oil consumption increase is about equal to economic growth, wouldnt it make sense to use oil as quickly and efficiently as possible? money makes money and the more we have, the more can be used in R&D when the crunch actually arrives.
then again, i think the green party, like any other political party, only really looks as far ahead as the next election. and the 'peak oil' tosh is another baseless pariah useing high prices to scare idiots into thinking were gonna run out or have already passed the peak.

WHBM

2nd Oct 2006, 16:48

Lockheed did a lot of work on this in the 1970s with designs for a hydrogen-fuelled Tristar. I don't know whether they came up with insoluble technical issues or whether they just felt there was no commercial demand for it.

I recall a prototype was certainly going to be routed well away from any populated areas.

tribekey

2nd Oct 2006, 16:57

dudduddud
i'm in aviation, not a member in any way whatsoever of any 'green party' but through studying to degree level have had to accept that the evidence for global warming is beyond doubt. From U.N. publications, through government scientific studies, E.U. studies and endless other scientific studies ( as well as the more popular programmes such as horizon etc) the published evidence is overwhelming, Yes, green parties have been known to pick the most extreme predictions and damage their own credibility by doing so but are you saying that organisations like the u.k. met office, for example,are making it all up too? The greenhouse effect is real,the science is not difficult, the average temperature of the planet is increasing(the correlation between fossil fuel burning and co2 in the atmosphere over the last 150 years is too close to be coincidence), given that, it is hardly 'bull###' to call for reductions in co2 emissions. Aviation happens to be the fastest growing contributer at the moment so it's hardly surprising it's attracting attention,problem for aviation is that there is no alternative fuel at the moment.Tinkering with a few percent reduction is laughable,emissions need to drop by 60+%!
As for the oil supply, stating that we should consume oil as quickly and efficiently as possible is as extreme an argument as stating the world is about to end. Oil is a FINITE resource,you can argue over how much is left, 20 years, maybe 40 years supply but the hard ,cold fact is it will run out and before that it will run down.
When oil production starts to fall below demand then you have passed 'peak oil' point, not difficult to grasp. As demand outstrips supply then you have inflation of the price, look back at the various peak prices, they all match supply shortage or supply 'scares'.
Apart from anything else, we use oil for so much of our modern 'stuff' that frankly we'd be like lost children without it,look around your house, plastic window frames,plastic keys on your laptop, packaging,some medicines,paints,etc etc etc.all of these things will either have to be changed or done without.
Given that we could use hydrogen as a fuel,at least for all ground/sea transport and we can create it using solar photovoltaic cells then encouraging movement in that direction is eminently sensible. So, how does aviation move in the same direction? Or is it immune? Waiting for 'the crunch' to arrive is insane,if you had a problem with your aircraft would you wait until that happened or sort a known problem out?

TSR22

2nd Oct 2006, 18:57

Hi,

Great ranting! Yea, its true that I couldn't put my hands on anything particularly good (and I can't today since I didn't give it another thought!)
One thing about scientists though (a little bias here - I am one when I'm not flying; only my area of expertise is medical which is why I don't save the "other" journals!) is that the work they do is well researched and peer reviewed by other experts. It is very difficult to fake work for one's own ends which is why there aren't many rich scientists (contrary to popular belief!)- Most of us are too boring for that:8
I agree about the NIMBYism - my local village is full of it as they're trying to place windfarms all around the locality (something which I support). I wonder, how much of a difference could be made if solar panels were compulsory, hybrid cars were the norm (I know they're not much better but they ARE better) and people were prepared to accept less packaging on their groceries. All little changes that gradually add up - just like aviation. I'm under no illusions about the amount of damage it causes relative to other activities (which are far more destructive) but if we could come up with something, then it is one less problem to worry about. Cars must be the worst polluter and I hope that the car manufacturers can get it sorted fast. Imagine all of the cars that are probably sitting at traffic lights with their engines ticking over for several minutes. Now imagine that, all over the country at every junction. Multiply that across the world and there is a lot of pollution going on..
p.s. I'm not a NIMBY:E . I take the train to work everyday (I could use my car), recycle, and turn off lights (and my engine at traffic lights!). We all have to do our bit - however small...