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Have you looked at fuel cells. There are lost of educational fuel cell kits available. http://www.fuelcellstore.com/en/pc/viewCategories.asp?idCategory=12

More information http://en.wikipedia.org/wiki/Home_fuel_cell If you want to buy them now. http://www.fuelcellstore.com/ How Fuel cells work http://www.fuelcells.org/basics/types.html

Yes, you can subsidize a hydrogen vehicle down to whatever price you want for PR. Want to see what hydrogen vehicles cost unsubsidized? $7,700 a month corresponds to about $500k purchase price. And that's not just a radical case; bulk fuel cells cost over $10/W, and one horsepower is about 750W, so that's about $7,500 per horsepower; I'll let you do the math. Just for the fuel cell stack. And then we get into efficiency -- or more appropriately, the complete lack of it in hydrogen-fuelled vehicles. A fuel-cell vehicle takes 2-4 times as much energy as an EV per mile travelled. A H2 ICE takes 3-6 times as much. Then there's hydrogen itself; it really is a nasty substance. Not toxic, but ozone depleting, metal-embrittling, explosive in almost any fuel-air mixture, readily undergoes deflagration-to-detonation transitions, burns clear, leaks through almost anything, incredibly non-dense (i.e., expensive to store), and on and on down the line. Then there's storage density, which now is barely better than li-ion (hasn't advanced nearly as fast as battery tech), and the filling time for hydrogen vehicles has actually been *increasing* as they try to up the storage density, to the point where it takes longer to fill one of the latest generation of hydrogen vehicles than it does to charge titanate batteries, and nearly as long as it takes to charge phosphates and spinels. Then there's longevity, freezing, moving part count, fuel purity, and on and on... read the link I provided; there's a lot more in there.

In short, hydrogen is the perfect answer if you can spend someone else's money and want to do three times as much environmental damage for no real benefit but increased complexity and risk.

Fuel cells are not "a good thing". They're an incredibly expensive boondoggle that's been leaching money from electric vehicles. Let's compare and contrast FCVs with BEVs that use modern automotive li-ions (phosphates, stabilized spinels, titanates, etc).

They're roughly a third the efficiency of EVs. Even if you use cleantech to create the hydrogen, you're still talking three times the coastline covered in wind turbines, three times the desert land covered in solar, three times the rivers dammed for hydro, etc -- not good. Even if your electrolysis was near lossless, as a couple techs in the lab are proposing to do, they're still nearly twice as wasteful as EVs. Even hydrogen from natural gas reformation compared to EVs powered by natural gas power plants is *still* significantly more wasteful for fuel cells ((25% efficiency versus 35%).

Hydrogen is expensive; electricity is dirt cheap. Hydrogen is fundamentally always going to be more expensive because it's such a PITA to handle -- leaks through practically anything, embrittles metals, is corrosive, etc -- and not to mention, poses safety and environmental risks.

Safety? Autmotive li-ions can be abused to heck and back without starting a fire -- discharged to 0V, overcharged, punctured, etc; the electrolyte is generally flammable, but no moreso than gasoline. Hydrogen is an incredibly combustible substance -- burns in almost any fuel air mixture, very vigorously, with a very pale blue, hard to see flame; rapidly evolves deflagrations into detonations in atmospheric conditions; pools under overhangs; can be ignited with less than a tenth the ignition energy of gasoline; enters pipes and tubes and follows them to their destinations, pooling there; etc. Liquid hydrogen is even worse; it acts like a high explosive. Check out NASA's safety guidelines for dealing with hydrogen to get an idea of how much of a pain it is to handle.

Fuel cells are ridiculously expensive. Here, go shopping. A good chunk of that price is due to the price of platinum, one of the rarest elements on the planet, although things like Nafion membranes don't help the price, either. Getting fuel cells for $10/W would be an outstanding price. Your average car will need ~10kW to maintain highway speeds, and more for accel/decel, so you're looking at hundreds of thousands of dollars. Automotive li-ions, except for the titanates, are usually a little over $0.50/Wh in bulk, and are projected to significantly decline with mass production, since they're not raw materials costs limited. A couple tens of kilowatts (a couple hours of driving at highway speeds) means $10-20k currently, and significantly less in the near future. And to top it all off, the batteries last longer, too. Nafion membranes tend to wear out over time in fuel cells, giving them around five years or so in typical FCV usage (some techs are proposed to raise that). And there are other components to break, too -- fuel cells have moving parts (compressors, pumps, etc), support parts (heaters, etc), and so on. Automotive li-ions will generally last for thousands to even tens of thousands (in the case of the titanates) of cycles. We're talking decades. To give an idea of how durable they are, the Volt is going to come with a 10 year warranty on its battery pack, and all of the other upcoming EV/PHEV makers are similarly talking about very long warranties. They should last the life of the car.

As for range, it's roughly a draw. 200-250 miles is a typical range for a FCV that costs hundreds of thous

A large fuel cell stack will cost you around $10 a watt (smaller ones are more expensive per watt). Let's say that some big fuel cell manufacturer and can afford to sell them in bulk for $5 a watt. Well, go check out your breaker box. How many watts is it rated for -- 30kW? 50kW? 100kW? That's hundreds of thousands of dollars worth of fuel cells alone. Not exactly affordable. Even if you were to use a battery or capacitor buffer so that you only need to be able to provide a fraction of that, it's still priced way out of any semblance of affordability. Of course, you don't *have* to use fuel cells. You could use a H2 ICE or turbine. But then your efficiency is *even lower*.

Batteries are really the only realistic option in the foreseeable future.

http://www.fuelcellstore.com/ Sells units for 50k!!! See http://www.fuelcellstore.com/cgi-bin/fuelweb/view= NavPage/cat=31

http://www.fuelcellstore.com/ Sells units for 50k!!! See http://www.fuelcellstore.com/cgi-bin/fuelweb/view= NavPage/cat=31

In more rural ares people tend to store a lot of propane and sometimes gasoline (but usually diesel in these cases, and diesel is fairly safe, you can put a fire out by throwing diesel on it(depending)). Even in some not so rural areas tanks like this 250 gallon one are not at all uncommon. Granted you don't see much of that manner of thing in the burbs or in cities but a comparable hydride tank is much much smaller, in fact it's about the size of a 20 gallon gasoline tank.

Given that the hydrogen is stored in a metal hydride, yes, it is far safer to store the hydrogen in large quantities than it is to store gas in your car. You cannot ignite a metal hydride, even if the tank was ruptured and completely compromised.

So, I will go telling you that, because it's true. But, the price is indeed a bit daunting.

Look up (MCEL) Millenium Cell, They've been doing this for awhile. I believe the chemistry for this has been around a while too lazy to look it up tho. Platinum Catylitic mesh, and Borohydride The fuelcellstore has a nice little generator --G

I always thought this was cool, when I saw it like 3 1/2 years ago

In World Solar Congress 2006 in Orlando Fuel Cell Store was selling hydrogen powered cars with a solar panel that can 'extract' hydrogen from pure H20. Here's the link to all models avaiable: http://www.fuelcellstore.com/cgi-bin/fuelweb/view= NavPage/cat=14 C2

Yea, all I searched for was "mea", but not "dmfc." The least expensive dmfc is indeed $69.50.

http://www.fuelcellstore.com/cgi-bin/fuelweb/view= SearchResults/command=LogSearch?searchfor=dmfc

here's the link, from the same website:
http://www.fuelcellstore.com/cgi-bin/fuelweb/view= Item/cat=/product=302

and here's the search result that yielded it:
http://www.fuelcellstore.com/cgi-bin/fuelweb/view= SearchResults/command=LogSearch?searchfor=mea

here's the link, from the same website:
http://www.fuelcellstore.com/cgi-bin/fuelweb/view= Item/cat=/product=302

and here's the search result that yielded it:
http://www.fuelcellstore.com/cgi-bin/fuelweb/view= SearchResults/command=LogSearch?searchfor=mea

Where'd you get $47.50? Looking at the site recommended in TFA, the part (here) costs $69.50.

well, just open google, type in "UPS Fuel cell" and thell me you haven't seen them ...

I haven't seen them. The products you're pointing to, and I could find only one place selling them, cost $20k! That does not support any assertion of technology we'll see in cell phones tomorrow. Hell, that's not even cost effective compared to a battery backup or a gas generator at the same level. When they can replace my $120 desktop UPS, then we might be able to start talking about fuel cell phones in a year or two.

OK, burn coal or gasoline and the nitrogen stays in the air and doesn't chemically combine with anything. If you don't burn it in air....

But if the air gets hot (like in any thermal engine), some nitrogen reacts with some oxygen and you get some NOx. And hydrogen is pretty much the same or somewhat worse than gasoline with respect to this property depending on how you look at it.

If you look at the autoignition temperatures (the lowest temperature a fuel will burn) hydrogen's is 530 C. And the autoignition temperature of gasoline is about 260 C. So you can make gasoline produce much less NOx than hydrogen with some effort.

Hydrogen's flame temperature is 2045 C in air. Gasoline's is 2197 C, almost the same. This is the worst case temperature for the two. Sloppy engines will probably put out about the same NOx.

(Info from http://www.fuelcellstore.com/information/hydrogen_ safety.html,
http://www.hut.fi/Units/AES/projects/renew/fuelcel l/posters/hydrogen.html and http://hypertextbook.com/facts/2003/ShaniChristoph er.shtml.)

Fuel cells don't store electricity, they produce it. The electricity we're talking about storing here is produces by wind turbines. How would you get this electricity into a fuel cell? It's not like you can just run a fuel cell backwards --> apply electricity to it and get hydrogen out and store the energy chemcially until needed.

Really? this must be a figment of my imagination then. How silly of me.

No, which is still a long way from a fuel cell one of these.

Actually there are fywheel energy systems around.

But for the small home user, they are not practical. Also, something spinning that fast with that much mass makes me quite nervous.

Most people do not live near a creek and do not have space for a water reservoir storage system. This is probably the case here as he is wanting to use photovoltaics.

This is why everybody is clamoring to get a fuel cell to work.

He could use the excess energy to generate hydrogen and feed it to a fuel cell later to use as he needs.

Fuel cells are available, but they are beset with problems. They are expensive because many use rare metals as catalysts. They have limited lifetimes, needing repalcement every couple of years, making them very uneconomical at today's prices.

So while fuel cells may be the ideal, he may be stuck with batteries.

The EGen product on fuelcellstore is good way to get a H2 source (just start with NaBH4 and water) :-
http://www.fuelcellstore.com/cgi-bin/fuelweb/view= item/cat=3/subcat=17/product=353


It creates loads of hydrogen too.

For this homebrew effort, I personally think that the "sacraficial anode" type of fuel cell is one that could be done most easily. In these types of fuel cells, a metal anode is decomposed in an electrolyte solution, and it is this decomposition that is used to convey the charges, thus creating the voltage potential. First, take a look at this link. This is from the fuel cell store website which was mentioned by the submitter. This link show a product that the store carries which is a sacraficial anode fuel cell. The anode in this case is magnesium-based, the electrolyte is salt water. The cathode is a so-called "diffusion cathode", which performs an oxygen-interface with the surrounding air, via a semi-permeable membrane. This membrane is such that oxygen is allowed in, but the salt water inside stays inside.

Now, this company that supplies this cell to the fuel-cell store gives a good explanation of what is going on. However, it is different from what I remember. I remember that they used to sell a different such fuel cell - one in which the sacraficial anode was alluminium, not magnesium. I can't remember what the chemical reaction was, but it was nearly identical to what goes on with the magnesium based cell. Seeing this, I realized that such a homebrew cell might be possible.

The question is, what to use for materials? Here's the answer I have come up with:

1. Get a piece of PVC pipe with an end cap. Drill a bunch of holes in it, in a pattern of some sort. The more holes, the better, but make sure it is left structurally sound. Install the end cap.

2. Construct a cardboard tube such that its diameter is approximately 1-2mm less than the inside diameter of the PVC pipe.

3. Around this cardboard tube wrap a single layer of stainless steel mesh cloth. Around this wrap a single layer of polyethylene or polypropylene plastic.

4. Slide this inside the PVC pipe. This is your diffusion cathode.

5. In the center of another end cap, attach an alluminium rod. This is your anode.

6. Fill the pipe with a mostly saturated-salt water solution. Insert alluminium rod and cap. The rod should not touch the sides, but instead should hang down the middle of the pipe. Keep the pipe vertical, leave room for air circulation.

7. Profit?

Now, I don't know if this will work. I have not tried it. But I think somewhere in it is gem of truth on how a homebrew fuel cell could be made. The hardest (and most expensive) portion of a fuel cell is the membrane. I think something like cling wrap or plastic freezer could supply the membrane - some kind of plastic that "breaths", and lets air through.

So, could a homebrew fuel cell be made? Try it, and see!

Hydrogen is not that explosive. In many ways a hydrogen powered vehicle would be safer than a gasoline powered vehicle. Since hydrogen is a gas, it tends not to stick around in one place once it leaks. It also tends to be less volatile than gasoline. Check out this page.

Most people assume that hydrogen is disproportionately dangerous because of the Hindenburg disaster. The fact is that if gasoline powered engines were invented today, gasoline is volatile enough that they would be considered too unsafe to be approved.

When hydrogen approaches levels of 4% concentration in the atmosphere, the possibility of it igniting increases greatly. A concentration level of 4% for hydrogen does not seem that high, but when compared to gasoline, which is 1%, hydrogen offers a significantly lower risk of explosion. Gasoline becomes volatile at a concentration 4 times lower than that of hydrogen.

It's common to store hydrogen in a tank of metal hydride chips. The tank doesn't have to be as strong, and cyrogenic temperatures aren't required. It's also far safer; if damaged, the hydrogen comes out slowly as the hydrides outgas, so at worst you get a fire, not an explosion.

you can buy a fuel cell kit at
the fuel cell store

They claim that 81W are waiting to be harvested from a sleeping human. This is incorrect, due to Carnot's law (a thermodynamic law). Basically if we have a heat source at Th (the body) and a heat sink at Tl (the environment) the maximum possible efficiency is

1- Tl/Th

All temperatures must be in Kelvin (or Rankine). So for a human at 37C = 310K, with an environment at room temperature 20C = 293K, the best efficiency is

1 - 293/310 = 5.5%

If they can get 3% efficiency with current materials, they're already doing extremely well. At this efficiency a sleeping human, putting of 81W of heat, can only provide

81W * 5.5% = 4.4W

of usable energy. It's true that 4.4W can power a fair bit of energy-efficient technology, but they're starting with a lot less available energy than they claimed in the article.

Here, why don't you buy one. This little demo unit is about the size of a clock radio and consists of a solar cell that generates the hydrogen, and then a fuel cell that uses that hydrogen to run a little electric motor.

The same people have all sorts of other little fuel cell toys, but they ain't cheap.

Here, why don't you buy one. This little demo unit is about the size of a clock radio and consists of a solar cell that generates the hydrogen, and then a fuel cell that uses that hydrogen to run a little electric motor.

The same people have all sorts of other little fuel cell toys, but they ain't cheap.