Why all the excitement of fuel-cell vehicles?

[Mark R]

I appreciate the growing need to find an alternative energy form for transportation, but find the fuel-cell to be a rather uninspiring. If we use hydrogen, which is probably the most practical energy carrier then there are other ways of using it.

Fuel cells are bulky, weighty, highly inefficient and phenomenally expensive - a large proportion of the cost coming from the large quantities of precious metals needed for construction. Currently mass produced hydrogen fuel cells cost about $4k per horsepower - you know that little Honda concept car, it might be road legal, but Honda won't sell it, because they'd scare you off with the price tag. Of course that cost could be very significantly reduced by massive scale manufacture, but there is still the problem that current fuel cell technology needs about a 1/4-1/2 oz of platinum per horsepower.

Why then haven't the car manufacturer's opted for an alternative technology for hydrogen propulsion? - one that is easily manufactured in huge quantities, on current production lines; is mature and widely installed and can be built for about $40 per horsepower. I'm thinking of the conventional internal combustion engine as used in cars today - both Otto and Diesel variants. It's a very straight-forward conversion to modify a gasoline engine to run on hydrogen or other gaseous fuel - the modifications should be able to be retro-fitted by any compentent mechanic. I'm sure that given enough motivation the few obstacles in making a practical hydrogen diesel engine could soon be overcome. Of course, being powered by hydrogen means that a conventional engine, just like a fuel cell, will emit only harmless water in the exhaust.

Yes, burning the hydrogen is less efficient that a fuel cell - but it would be a viable technology to help build a hydrogen infrastructure, if that is what will be needed for the next century. Personally, I don't see fuel cells being a practical proposition for 15-20 years (but I would like to be surprised) but modified IC engines are viable now, all that is needed is a hydrogen supply.

Typical numbers pulled from various white papers suggest that a typical car has an efficiency of about 25-30% after drive-train losses. Ultra-high efficiency fuel cells manage about 60% - which after electronic and motor losses is probably down to about 45-50% at the wheels. Both could be improved to some extent with hybrid technology and regenerative braking. If you use an alcohol reforming fuel-cell (which uses liquid fuel) then efficiencies are even poorer - probably 45-50% for the cell alone - leaving pitifully little improvement over conventional technology.

So, why ignore H2-powered or alcohol powered conventional engines when fuel cells are likely to provide little benefit in terms of fuel consumption?

 

[spyordie007]

Found this off a search, things slip through the cracks very quickly in OT...

We at the AHANW promote using existing internal combustion engine technologies to burn hydrogen rather than fossil fuels as an interim (basically until fuel cells can be mass produced cheaply). For more information please check out our website (link in my signature).

While we are on the topic we are having a contest designing banner advertisements for our new online store and are giving away a FREE copy of the book "The Philosopher Mechanic." If you're interested the Philosopher Mechanic is a great read and it focuses on economically viable existing solutions. Check it out:
http://www.ahanw.org/forum/topic.asp?TOPIC_ID=372
/plug

-Erik

 

[Chaotic42]

1. How will you carry the Hydrogen? At room temperature, it would be very inefficient to carry hydrogen. Sure it's light, but you'd need a huge tank. If you compress it, you risk an even larger fire hazard. If you supercool it, you're talking about huge amounts of energy to keep it that cold.

2. Where would you get it from?

3. Hydrogen burns pretty hot, it seems like it would cause more wear and tear on the engine.


Anyway, I think Hydrogen will be the fuel of the future, but in what form I'm not sure. I read somewhere that four grams of helium contain as much energy as sixty tons of fuel oil can produce through current methods.

 

[silverpig]

Originally posted by: Chaotic42
1. How will you carry the Hydrogen? At room temperature, it would be very inefficient to carry hydrogen. Sure it's light, but you'd need a huge tank. If you compress it, you risk an even larger fire hazard. If you supercool it, you're talking about huge amounts of energy to keep it that cold.

2. Where would you get it from?

3. Hydrogen burns pretty hot, it seems like it would cause more wear and tear on the engine.


Anyway, I think Hydrogen will be the fuel of the future, but in what form I'm not sure. I read somewhere that four grams of helium contain as much energy as sixty tons of fuel oil can produce through current methods.

That's if you use the helium for fusion... Something we can do in bombs, with gigawatt pulsed lasers, megawatt tokamak magnetic constrictors, and perhaps a very few other methods. What the kicker is, is these aren't even at break even point yet (you use more energy to get the reaction going than you get out of it), although we're getting close.

 

[TitanDiddly]

I like the idea of Hydrogen ICE.

1. How will you carry the Hydrogen? At room temperature, it would be very inefficient to carry hydrogen. Sure it's light, but you'd need a huge tank. If you compress it, you risk an even larger fire hazard.

They compress it to 20k PSI or higher. "

Explosion!?!

No more risk/danger than a gas tank. Their words, not mine.

 

[ClueLis]

Originally posted by: Chaotic42
1. How will you carry the Hydrogen? At room temperature, it would be very inefficient to carry hydrogen. Sure it's light, but you'd need a huge tank. If you compress it, you risk an even larger fire hazard. If you supercool it, you're talking about huge amounts of energy to keep it that cold.

Hydrogen is often stored in liquid metal hydride tanks, which chemically store th hydrogen to keep pressures at a reasonable level. Also, the fire hazard isn't that bad while it is in the tank.

2. Where would you get it from?

There are multiple processes being looked at for obtaining hydrogen. One is using a reformer, which would rip hydrogen atoms off to use as gas. An electrolyzer breaks water (which is the end product of the fuel cell anyway) into hydrogen and oxygen. Both of these methods require external energy, which would have to be supplied by a solar cell or some other source.
Another option is using using methanol instead of hydrogen, and adding a rubidium catalyst to the platinum already there.

3. Hydrogen burns pretty hot, it seems like it would cause more wear and tear on the engine.

You are using much less hydrogen than you would in an internal combustion engine, so the heat is virtually a nonfactor. Some types of fuel cells actually need to be heated to extreme temperatures to work, while other can operate at near room temperatures.

Anyway, I think Hydrogen will be the fuel of the future, but in what form I'm not sure. I read somewhere that four grams of helium contain as much energy as sixty tons of fuel oil can produce through current methods.

I believe that's fusion energy, not the type of redox reaction seen in fuel cells.

 

[ClueLis]

Originally posted by: Mark R
I appreciate the growing need to find an alternative energy form for transportation, but find the fuel-cell to be a rather uninspiring. If we use hydrogen, which is probably the most practical energy carrier then there are other ways of using it.

Fuel cells are bulky, weighty, highly inefficient and phenomenally expensive - a large proportion of the cost coming from the large quantities of precious metals needed for construction. Currently mass produced hydrogen fuel cells cost about $4k per horsepower - you know that little Honda concept car, it might be road legal, but Honda won't sell it, because they'd scare you off with the price tag. Of course that cost could be very significantly reduced by massive scale manufacture, but there is still the problem that current fuel cell technology needs about a 1/4-1/2 oz of platinum per horsepower.

This is the biggest problem in fuel cells right now. If someone could find a cheaper catalyst, everything would be solved. Unfortunately, that isn't proving easy.

Why then haven't the car manufacturer's opted for an alternative technology for hydrogen propulsion? - one that is easily manufactured in huge quantities, on current production lines; is mature and widely installed and can be built for about $40 per horsepower. I'm thinking of the conventional internal combustion engine as used in cars today - both Otto and Diesel variants. It's a very straight-forward conversion to modify a gasoline engine to run on hydrogen or other gaseous fuel - the modifications should be able to be retro-fitted by any compentent mechanic. I'm sure that given enough motivation the few obstacles in making a practical hydrogen diesel engine could soon be overcome. Of course, being powered by hydrogen means that a conventional engine, just like a fuel cell, will emit only harmless water in the exhaust.

Yes, burning the hydrogen is less efficient that a fuel cell - but it would be a viable technology to help build a hydrogen infrastructure, if that is what will be needed for the next century. Personally, I don't see fuel cells being a practical proposition for 15-20 years (but I would like to be surprised) but modified IC engines are viable now, all that is needed is a hydrogen supply.

Typical numbers pulled from various white papers suggest that a typical car has an efficiency of about 25-30% after drive-train losses. Ultra-high efficiency fuel cells manage about 60% - which after electronic and motor losses is probably down to about 45-50% at the wheels. Both could be improved to some extent with hybrid technology and regenerative braking. If you use an alcohol reforming fuel-cell (which uses liquid fuel) then efficiencies are even poorer - probably 45-50% for the cell alone - leaving pitifully little improvement over conventional technology.

So, why ignore H2-powered or alcohol powered conventional engines when fuel cells are likely to provide little benefit in terms of fuel consumption?

I definitely wouldn't ignore them, but fuel cell effiency is still higher, and of great enough benefit that people might see it worthwhile completely redesigning the system.

 

[Chaotic42]

Originally posted by: ClueLis
I believe that's fusion energy, not the type of redox reaction seen in fuel cells.

Yeah, it is. I was just trying to show how much farther we have to go.

 

[spyordie007]

Although I'd rather you post the questions in our forum I'll answer these ones quickly since they are pretty easy.

1. How will you carry the Hydrogen? At room temperature, it would be very inefficient to carry hydrogen. Sure it's light, but you'd need a huge tank. If you compress it, you risk an even larger fire hazard. If you supercool it, you're talking about huge amounts of energy to keep it that cold.

Actually while compressed it is not a fire hazard because there is no oxygen (which is why NASA has to carry so much oxygen along with their hydrogen rocket fuel).

2. Where would you get it from?

There are 2 common ways of getting Hydrogen, Electrolosys and BioMass decomposition.

In electrolosis electrical energy is used to split water into hydrogen and oxygen gas (the oxygen gas is actually worth much more than the hydrogen if kept clean/pure). The caveot to this method is that you cant claim it is "clean" unless the electricity is coming from a "clean" source.

With biomass you can get hydrogen a couple of way, the simplest (yet least efficient and least clean) is to allow regular decomposition to yield methane gas and than run it through a reformer. You have other *better* options however they become more complex such as using specially engineered bacteria for the decomposition you can litterally have hydrogen gas released rather than methane, this is complex though since it requires a very sterile enviroment. You can also subject the regular run-of-the-mill bacteria to a specific series of electric bursts and it will produce hydrogen, the disadvantage to this is that it requires you provide the electric power from somewhere. The neat thing about any biomass method is that you can refine other materials out of the "leftovers" (fertilizers, carbon for manufacturing, etc.).

3. Hydrogen burns pretty hot, it seems like it would cause more wear and tear on the engine.

Yes it does burn hotter than gasoline however it burns quicker and cleaner so the heat dissapates much quicker. As per our research internal combustion engines that run off of Hydrogen will last much longer than those run off of gasoline because there are no carbon deposits that remain in the engine compartment from the burning of the fuel.

Anyway, I think Hydrogen will be the fuel of the future, but in what form I'm not sure. I read somewhere that four grams of helium contain as much energy as sixty tons of fuel oil can produce through current methods.

I'm not sure if you meant to say Hydrogen or not; helium in its natural state is inert. Whichever the case it doesnt much matter because if you are comparing 4 grams to 60 tons you are probably refering to nucular fusion which is not something I support.

Also as I said before we've got some great books on it, if you are capable of producing a banner advertisement you've got a chance at getting one FREE too

-Erik

 

[silverpig]

Why are you against fusion?

And hydrogen, whether compressed or not is always a fire hazard. Sure there's no oxygen in the tank, but there's a whole ton of it in the air we breathe. Get a leak in the tank or lines, and a spark and you're fvcked.

 

[Chaotic42]

Originally posted by: spyordie007
Actually while compressed it is not a fire hazard because there is no oxygen (which is why NASA has to carry so much oxygen along with their hydrogen rocket fuel).

Well, I'm thinking about when a car wreck breaches the Hydrogen tank.

Yes it does burn hotter than gasoline however it burns quicker and cleaner so the heat dissapates much quicker. As per our research internal combustion engines that run off of Hydrogen will last much longer than those run off of gasoline because there are no carbon deposits that remain in the engine compartment from the burning of the fuel.

That's cool.

I'm not sure if you meant to say Hydrogen or not; helium in its natural state is inert. Whichever the case it doesnt much matter because if you are comparing 4 grams to 60 tons you are probably refering to nucular fusion which is not something I support.

Yeah, I was referring to the nuclear fusion of 4 grams of helium, compared to the burning of 60 tons of oil. Sorry if I was unclear.

Why don't you support nuclear fusion?

 

[spyordie007]

Not that I have a serious problemwith nuclear fusion, just that it's not something I know or support in my actions. The biggest problem I've seen with any nuclear power is that the final energy output has never been enough to offset the overall costs (I'm refering to all costs, production, insurance, labor, enviromental, cleanup, containment etc., not just input/output costs).

And hydrogen, whether compressed or not is always a fire hazard. Sure there's no oxygen in the tank, but there's a whole ton of it in the air we breathe. Get a leak in the tank or lines, and a spark and you're fvcked.

Yes definetly I agree. Hydrogen is a fuel, it contains energy and it burns.

The neat thing about hydrogen fires/leaks of the nature you're explaining is that they are far less serious than those with gasoline. Think about your tank full of gasoline, if it ignites you have a nasty bomb that explodes out in all directions.

Because hydrogen is so much less dense then the atmosphere and you need it mixed with oxygen before it will burn what you end up with in a hydrogen fire is a flame that starts 20 feet up and moves esentially in a single direction (straight up). This is one of the reasons I consider hydrogen safer than gasoline.

In many ways hydrogen gas acts like natural gas, we've got some great videos that we use for learning materials about the safety of natural gas in automobiles.

-Erik

 

[spyordie007]

ugg, somebody just pointed out to me that the contest was posted to an area on our forums that was not publicly accessable. I've fixed it so you guys can get to it.

-Erik

 

[Analog]

Anybody for cold fusion?

 

[Chaotic42]

Originally posted by: spyordie007
Not that I have a serious problemwith nuclear fusion, just that it's not something I know or support in my actions. The biggest problem I've seen with any nuclear power is that the final energy output has never been enough to offset the overall costs (I'm refering to all costs, production, insurance, labor, enviromental, cleanup, containment etc., not just input/output costs).

Well, that's nuclear fission. I don't think that nuclear fusion has been achieved at all by humans yet, but I could be wrong.

flame that starts 20 feet up and moves esentially in a single direction (straight up). This is one of the reasons I consider hydrogen safer than gasoline.

Unless you end up on top of a car in a wreck.

I'm not trying to put it down, I'm just playing devil's advocate.

 

[The Stigenator]

i will responsd to the thread later on..

 

[Chaotic42]

Originally posted by: spyordie007
ugg, somebody just pointed out to me that the contest was posted to an area on our forums that was not publicly accessable. I've fixed it so you guys can get to it.

-Erik

I might just enter it. When I get back from getting dinner, I'm going to pick your site apart for the delicious information within.

 

[Chaotic42]

Originally posted by: The_good_guy
i will responsd to the thread later on..

We don't respond to threats.

 

[silverpig]

Originally posted by: Chaotic42

Originally posted by: spyordie007
Not that I have a serious problemwith nuclear fusion, just that it's not something I know or support in my actions. The biggest problem I've seen with any nuclear power is that the final energy output has never been enough to offset the overall costs (I'm refering to all costs, production, insurance, labor, enviromental, cleanup, containment etc., not just input/output costs).

Well, that's nuclear fission. I don't think that nuclear fusion has been achieved at all by humans yet, but I could be wrong.

flame that starts 20 feet up and moves esentially in a single direction (straight up). This is one of the reasons I consider hydrogen safer than gasoline.

Unless you end up on top of a car in a wreck.

I'm not trying to put it down, I'm just playing devil's advocate.

Fusion has been achieved many times. The H-bomb refers to hydrogen bomb. That's fusion of deuterium (hydrogen 2) and tritium (hydrogen 3). Furthermore, controlled fusion reactions happen all the time, but are very inefficient.

 

[spyordie007]

Well, that's nuclear fission. I don't think that nuclear fusion has been achieved at all by humans yet, but I could be wrong.

err no fusion is what I meant, fission is where you put energy in and create matter...
http://www.jet.efda.org/pages/content/fusion1.html

Unless you end up on top of a car in a wreck.

If you're car is on top of a 20 foot tall wreak I think you've got more to worry about than the fuel used by the car on the bottom.

-Erik

 

[spyordie007]

Originally posted by: Chaotic42
When I get back from getting dinner, I'm going to pick your site apart for the delicious information within.

Please do.

 

[silverpig]

Originally posted by: spyordie007

Well, that's nuclear fission. I don't think that nuclear fusion has been achieved at all by humans yet, but I could be wrong.

err no fusion is what I meant, fission is where you put energy in and create matter...
http://www.jet.efda.org/pages/content/fusion1.html

Unless you end up on top of a car in a wreck.

If you're car is on top of a 20 foot tall wreak I think you've got more to worry about than the fuel used by the car on the bottom.

-Erik

No it's not. Fission is where you split a heavy nucleus, getting two lighter nuclei and energy. Fusion is the combination of two light nuclei to form a heavier nucleus along with energy.

 

[h2powerman]

And hydrogen, whether compressed or not is always a fire hazard. Sure there's no oxygen in the tank, but there's a whole ton of it in the air we breathe. Get a leak in the tank or lines, and a spark and you're fvcked.

Actually this isn't entirely true. Hydrogen is a flamable gas and should be treated with respect. This said many of the tanks that are legal by DOT have been installed with internal and exterior valves, some even with flame arestors built in which in both cases help to prevent the tank from igniting or exploding, even in the case of a upside down vehicle. All tanks that are DOT certified also have static charge grounding devices for the tanks. So as you can see even with the high pressure, the natural ability that h2 has of being safe, it is nice to have multiple redundancy to keep the public from hurting themselves. Myself included. []

For more information please check out www.ahanw.org. Thanks!

 

[Regs]

Well if a fuel cell exploded you would likely be vaporized in a instant. But if a gas tank exploded you have a higher chance of burning alive in a horrible grizzly death.

 

[Lizardman]

Originally posted by: Mark R
I appreciate the growing need to find an alternative energy form for transportation, but find the fuel-cell to be a rather uninspiring. If we use hydrogen, which is probably the most practical energy carrier then there are other ways of using it.

Fuel cells are bulky, weighty, highly inefficient and phenomenally expensive -

Older fuel cells yes, new ones are much better. They are much light, cheaper and more efficient. The platium catalyst that the newer fuel cells use is atomized so they have to use very little of it for a typical PEMFC (Proton Exchange membrane). I don't think your esitmate of 4K per horsepower estimate is very accurate. A modern fuel cell designed for a car can output 75kW ~ 100hp. Which according to your estimate would be 400K just for the fuel cell.

FCs are much simpler to make than an IC engine. They are just a stack of repeating components.


FCs are silent which is a big plus. (just thought i would add that in)

Why then haven't the car manufacturer's opted for an alternative technology for hydrogen propulsion? - one that is easily manufactured in huge quantities, on current production lines; is mature and widely installed and can be built for about $40 per horsepower. I'm thinking of the conventional internal combustion engine as used in cars today - both Otto and Diesel variants. It's a very straight-forward conversion to modify a gasoline engine to run on hydrogen or other gaseous fuel - the modifications should be able to be retro-fitted by any compentent mechanic. I'm sure that given enough motivation the few obstacles in making a practical hydrogen diesel engine could soon be overcome. Of course, being powered by hydrogen means that a conventional engine, just like a fuel cell, will emit only harmless water in the exhaust.

Yes, burning the hydrogen is less efficient that a fuel cell - but it would be a viable technology to help build a hydrogen infrastructure, if that is what will be needed for the next century. Personally, I don't see fuel cells being a practical proposition for 15-20 years (but I would like to be surprised) but modified IC engines are viable now, all that is needed is a hydrogen supply.

Typical numbers pulled from various white papers suggest that a typical car has an efficiency of about 25-30% after drive-train losses. Ultra-high efficiency fuel cells manage about 60% - which after electronic and motor losses is probably down to about 45-50% at the wheels. Both could be improved to some extent with hybrid technology and regenerative braking. If you use an alcohol reforming fuel-cell (which uses liquid fuel) then efficiencies are even poorer - probably 45-50% for the cell alone - leaving pitifully little improvement over conventional technology.

So, why ignore H2-powered or alcohol powered conventional engines when fuel cells are likely to provide little benefit in terms of fuel consumption?