Boeing to Develop a Fuel Cell Powered Airplane

gilgsn writes: "From Yahoo News: Boeing is working with a light airplane manufacturer in Spain on a fuel cell powered plane. The efficiency of electric motors, with their reliability, acceleration, lack of vibrations and noise has a lot to offer to general aviation. The project aims at exploring environmentally friendly modes of propulsion. I can easily imagine a hybrid aircraft using fuel cell technology for take-off and altitude gain, coupled with solar cells to sustain flight. I hope a kitplane manufacturer in the United States will read this. I can't wait to fly a fuel cell powered ultralight!" CD: The question is can a fuel cell deliver enough energy for a flight long enough to be practical.

Comments

Which Fuel?

[squaretorus]

With Fuel Cells you boil down to a trade off between the efficiency and cost of the fuel.

Plain old hydrocarbons are cheapish, easy to handle, and not overly dangerous in a 'leak' situation.
But they require hyper advanced self cleaning fuel cells that wear out quickly.

Pure methanol is expensive (purification always costs), easy to handle, and not overly dangerous in a leak situation.
It works in cheaper, more reliable, longer lasting and lighter fuel cells.

Hydrogen is expensive, difficult to handle, and pretty damn dangerous stuff in ANY situation.
It works best with fuel cells, pretty much optimal.

A fuel cell that can handle ANY carbon rich material, and takes O2 from the atmosphere would be the holy grail. You could use argicultural by products to produce methonal, dig up oil, LPG, any burnable liquid essentially.

A rethink on the air network strategy to produce lighter, smaller, more efficient aircraft which possibly fly a bit slower and take shorter 'hops' would bring Fuel Cell flight closer.
This would be a worthwhile trade off for a more environmentally sound and sustainable flight infrastructure.

Boeing and Airbus both seem committed to increasing the size of aircraft overall. Maybe its time for a serious rethink?

Re:Which Fuel?

[Rogerborg]

• Hydrogen is expensive, difficult to handle, and pretty damn dangerous stuff in ANY situation

What's so dangerous about hydrogen in "ANY" situation? AFAIK, the big danger is leakage during storage, which is harder to detect than a leak of hydrocarbon vapour. A leak in use - in a moving vehicle - isn't significantly more likely than a hydrocarbon leak, nor more dangerous, as you have to be very unlucky to achieve the right fuel/air mixture at the right ignition point for sustained combustion.

Is this some Hindenburgh knee jerk response? The Hindenburgh was painted in a substance not dissimilar to rocket fuel, and even so, 61 of the 97 people on board survived. That's a pretty good survival rate for an aircraft that exploded on landing.

References that demonstrate the danger of hydrogen in "ANY" situation would be greatly appreciated.

The airline industry wanted this for years

[Billly Gates]

This is definitely good news. Not for the technology or environment per say but for political stability in the middle east and terrorism. Ibet none of you have any idea of how much power the oil indistry has to suppress such research for years on in.

The oil industry has such an effect in this country that its totally unbelievable (USA, for Europeans who hate American centered comments :-))! Basically they lobbied the FAA to make sure that fuel cell technologies for planes would never be approved. Boeing who is afraid of developing an engine that the energy-industry sponsored FAA would not allow them to sell, decided to only research fuel cell technology but not build any prototypes for obvious reasons.

However the September 11 attacks changed this. I was within 2 or 3 blocks from the World Trade Center and it was not the plane attacks that brought the buildings down but over an hour of intense 2000F heat that melted the support beams. As much as 2 Olympic sized swimming pools of jet fuel went inside the 2 buildings. 200,000 gallons in total. I am amazed that the towers even stood for that long. I assume most of the 4,000 people who perished would of survived if it wasn't for the deadly fire and jet fuel. Many didn't make it out in time or the heat was so intense that the stairways actually melted where the fire was.

Another problem we have is politics in the middle east. Americans have historically been strict isolationists. I would like it to stay that way. This all changed during both world wars and also during the rise of the oil industry. The 1991 gulf war was not about the suffering of those poor Kuwaiti's but for Exxon's, enrons, as well as Mobile's stock prices and profits. Bush senior received large amounts of money from the oil industry and we went to war to defend there interests and their cash. This is what started this whole Afghanistan mess we are in now. This is why China and the Arab world views Americans as empirialists. We represent more of the British empire in early America more then our original government. Our taxes now are actually much higher then before the American revolution! Believe or not. No wonder they view us as self serving empirialists. We actually are. Saudi Arabia is oppressive and the latest posts here on slashdot which state there intent to block internet access confirms this. We have no reason to support them other then for our energy interests. The sooner we lossen the oil industries grip the better. Also the Israeli's are being persecuted by terrorists groups funded by Arab's. I am aware the same can be said of the Palestinian persecution but when one group attacks another they both point fingers at each other and become more militant and oppresive. Before the 1950's the Arabs were all poor and lived in third world conditions. They ignored Israel before they had the money to fund Hummus. Thank oil for changing this. Anyway greed is bad and I am glad the government now is realizing that our dependence on foreign oil is bad. I believe fuel cell technology is the wave of the future for not only planes but cars as well.

Tandential benefits.

[karlm]

The biggest problem with fuel cells in airplanes should be the weight and bulk of the entire system. This is especially true for small aircraft. However, fuel cells provide many befets, especially compared to the piston engines used in sport aircraft.

The article mentions that fuel cells are twice as efficient as heat engines. I thought the efficiency gap was larger. In any case, the laws of thermodynamics place an upper limit on the efficiency of a heat engine (such as a turbine or piston engine). This upper limit is known asw the Carnot efficiency. It is determined by the ambient temperature and the temperature of combustion. 30% is a decent estimate of the Carnot efficiency for a gasoline engine with the ambient temperature about room temperature. I thought fuel cells were about 80% efficient, but then again I'm on a coding break at 5 a.m.

The MGM brushless DC motor developed at NTU in Australia has an efficiency around 99%.

The main advantages of fuel cells for sport aviation are the extremely high efficiencies and the good reliability of the components. Electrical components and non-moving mechanical components have much higher reliability/cost ratio than their moving counterparts. I've held aircraft pistons with valves imbedded in them. Some people much prefer the Wankel rotary engine in aircraft for its simplicity. Turbines are much better in terms of reliability, but their cost is much higher. One should also consider maintenance costs. An aircraft piston engine typically needs to completely overhauled every 20,000 hours of operation to ensure reliability. Fuel cell inspection and overhaul involves many fewer parts and is probably much cheaper and probably needs to be done less frequently. The same should be true for electric motors.

Another important factor in using electric motors is that the propellers can be designed more optimally if they don't have to deal with the large accelerations and decelerations that a 6-cylinder piston engine produces 3 times per revolution. Piston engines (even with flywheels) are very rough running, and propellers are beefed up so that they don't tear or shake appart under these loads. Any time you have to beef something up, you end up increasing the cost, weight, and/or innefiencies.

Let's not forget that most sport aircraft require 110 octane "low lead" fuel that is expensive and releases polluting lead compounds into the environment.

Re:Tandential benefits.

[FreeUser]

An aircraft piston engine typically needs to completely overhauled every 20,000 hours of operation to ensure reliability.

Very interesting post, but your decimal point is one off. My Lycombing O-360 (180 hp) engine has a TBO of 2000 hours, though I wish it were 20,000. :-) Airframes typically outlast multiple engines if they're well cared for, particularly if they're hangared (which mine is).

When it comes time to overhaul or replace my engine I'd love to replace it with a hydrogen fuel cell system (which is far less explosive than 60 gallons of 100LL), assuming I could get comparable performance from it. Not likely, of course, but one can dream.

Electric powered aircraft

[mactom]

Hi,

There are already several electrically powered aircraft flying. Ok, most of them are gliders that use the engine for take off and then retract it and continue flying, gliding and gaining altitude in thermals. But there is already a powered glider, the icare, which uses solarcells to power an electric motor for take off and sustained cruise.

Take a look at the following websites:

Lange Flugzeugbau
Icare
Silent AE1

Conventional self launching gliders are already very sophisticated, but the engines they use, require a lot of maintenance and are sometimes not as reliable as you might wish. Well anyway, if the engine fails I land on a field, no problem there, ... that is if a field is in range. Electric engines should increase reliability quite a lot. Hopefully they are available soon.

Regards, Thomas.

Brief Lesson On Hydrogen Safety

[Self Bias Resistor]

What about the risk of explosion in a fuel cell? Hydrogen is very volatile - you need a really good system that prevents tampering, leakage, electrical activity outside the plane, and can withstand crashes. I'm thinking about the Hindenburg airship disaster here when making comparison at the moment. I'm not an expert on these things so I would really like to know how the gas used in the auxiliary unit would "burn" in comparison to hydrogen in the event of a disaster.

Flammable fuels are only explosive when it has mixed with air in a sufficient quantity to form a fuel-air mixture. This is different from volatility, which is a measure of how easily a compound turns into gaseous form (petrol/gasoline, for example, is quite volatile, as is ethanol). The fact is that Hydrogen is the lightest element on the periodic table and hence diffuses through leaks and openings much more quickly than, say volatile fumes from regular petrol or JP9 jet fuel (where the fumes consist of multiple gaseous hydrocarbons, which have greater molecular weights and are hence much heavier). This is why there is no gaseous Hydrogen in the Earth's atmosphere. The Hydrogen simply floats away into space.

If you were to be involved in an accident involving an aircraft equipped with a Hydrogen fuel cell, you'd find that the chief cause will not have been the Hydrogen. The combustion of the fuel used in the aircraft's engines (remembering that the Hydrogen fuel cell will be used as a backup device to generate air and power for the aircraft and not as a means of propulsion) would have caused the lion's share of the damage. The only noticeable effect the Hydrogen would have on the acccident is to perhaps allow the fire to burn a little longer (assuming that enough of the Hydrogen is still contained in the air and has not diffused into the atmosphere). When being used in fuel cells, Hydrogen chiefly stored as a compressed, possibly liquefied gas. Hydrogen can also be stored in certain metallic compounds (known as metallic hydrides, which hold the Hydrogen atoms in a similar way to amalgum containing Mercury) to increase energy densities. In the first case, the rapid diffusion of the Hydrogen gas would not cause a fire for the reasons outlined above. In the second case, the Hydrogen would not be released because it is still bound to the metallic hydrides. In either case, it is unlikely that the cause of the accident will be the Hydrogen fuel. Hydrogen has, in fact, been proven to be a safer fuel to handle than gasoline. The byproduct of the fuel cell is water vapour, so it's also much better for the environment.

Your comparison to the Hindenburg disaster is not really applicable in this case, as it was conclusively demonstrated that it was the Aluminium compounds in the paint on the Hindenburg that caused it to burst into flames and not the Hydrogen gas. The Hydrogen ignited later, burning much more slowly and for a lot longer and hence actually acted as a fuel that sustained the fire, as opposed to the agent that caused the ship to burst into flames in the first place (remembering that the ship still burned even though the outer material had been completely destroyed).

Did ANYONE bother to read the article?

[John Harrison]

From the article:

Fuel cells and electric motors will not replace jet engines on commercial transports, but they could one day replace gas turbine auxiliary power units. Auxiliary power units, which typically are located in the rear fuselage with exhaust ports through the tail, are coupled to generators and compressors to produce electricity and air for airplane systems while on the ground and for backup use in flight.

Let me repeat, they are NOT trying to use fuel cells to replace the jet engines. They are going to use them to replace auxilary power units, which simply produce electricity.

So basically, this entire discussion here on /. is about the wrong thing! Not only is it about the wrong thing, but the thing that has been announced isn't that big of a deal. These are not electric aircraft that they are producing!

So move along now, the really is nothing to see here.

congrats Boeing, you're SECOND

[mr.ska]

A fuel cell-powered airplane is being worked on. Admittedly, it's not an airliner, but it's still the same problems, just on a smaller scale.

EVWorld.com has the two-part story and interview with the plane's builder here (1) and here (2).

Solar Cells

[Spudley]

I've always thought that aircraft wings are one of the most obvious places to put solar cells. On a day-time flight, you're practically garuanteed maximum sunshine for the whole duration.

Even if you don't use it directly to power the engines, there's still plenty of electronics on your average aircraft that could use it.