I drove some distance next to a Fuel Cell Toyota last night and was quite surprised by the amount of water exiting the tailpipe.

Not so much at slow speeds, where the output was just a few drops, but at highway speeds where it was like that little trickle of water you get when you just don't quite turn off the sink fawcett properly (know what I mean?).

I've said in casual conversation before, with never having seen a fuel cell vehicle in operation, that with everybody driving them we'd probably have treacherously wet freeways most of the time. This observation has done nothing to dissuade me from that prediction (though I admit it might be a little hysterial). I also mulled about what impact there may be on atmospheric humidity.

And what a waste of a valuable resource. There surely must be a way of recovering these emissions?

1 kg of hydrogen produces 8.94 kg of water.

1 kg of hydrogen produces 8.94 kg of water.

So what would that be in gallons?

So what would that be in gallons?

Depends on the pressure the hydrogen is under. 1 kg = 2.2 lbs. That is why you see storage tanks rated at psi. At 1 atm (STP) 1 kg of hydrogen is 22.4 L or 5.9 gal. So it all depends on the pressure at which the hydrogen is stored and in some systems, the hydrogen is stored in a solid, so it becomes even more complicated.

So what would that be in gallons?

But at STP, for water, 8.94 kg = 315.34922 ounces = 2.46366578 US gallons

Now that's a trick question. So I will have to assume water temperature of let us say, just starting to boil, but in full liquid state, at normal sea level atmospheric pressure, then the volume would be about 2.5 gallons.

Now that's a trick question. So I will have to assume water temperature of let us say, just starting to boil, but in full liquid state, at normal sea level atmospheric pressure, then the volume would be about 2.5 gallons.

That's what I thought, but didn't have enough confidence in my calculations to blurt it out.

That is an awful lot of water being expelled then, huh?

That's what I thought, but didn't have enough confidence in my calculations to blurt it out.

That is an awful lot of water being expelled then, huh?

Yes. And it should be considered near pure, should be good enough to drink if the tubes are not made of toxic metals or plastics (and their linings) and the input air is not dirty. At least, the water can be filtered easily. And you can drink it in case you find yourself standed.

I imagine that dry climates like California and Arizona would welcome the water, as they will be the first states to get fuel cell vehicles.

I imagine that dry climates like California and Arizona would welcome the water, as they will be the first states to get fuel cell vehicles.

Precisely. And to think that bottled water is even the world's greatest product scam. Maybe you can market your "assembled" pure water...

Then the only other question I have is how long it would take the average fuel cell car to consume said amount of hydrodgen.

I think the published range of the FCX Clarity is around 270 miles. Do we have any idea of the tank volume? I tried a Google search, but came up empty.

Tank volume will depend on temperature and pressure. I posted a reply here somewhere where it gives the dimension of a 2-kg capacity Kevlar tank that holds hydrogen. That type of tank is also used by Jetfighters and they jettison it from 36,000 ft or whatever height they are cruising, and then retrieve it back from the ground, undamaged. So it is a very safe tank. It may take a while before I find that post.

You won't be able to store your water in winter climates, so it will be poured out of the tailpipe. Cars are designed to drive on ice, and as long as drivers recognize that cold weather means driving as if ice could be anywhere, there is no problem. I've driven in CA when a rare occasion for icy streets occurred, and it was nuts. It's all about awareness and experience.

Tank volume will depend on temperature and pressure.

I think they were talking about 5000psi for the Clarity tank, if that helps any.

Found some GM figures on this very site for the fuel cell SUVs being used in Project Driveway -

"The SUVs......can store up to 4.2 kg of hydrogen, which will give 150 miles of range."

So let's generalize that these things are expelling up to a gallon of water for every 15 miles travelled. That means on my commute I would be expelling 4 gallons of water per day!

I would be ashamed of myself if I didn't figure out some way to utilize that. I feel shame now, just sitting her thinking about wasting it!

Just a word for Oregon... We might not even notice ;) because our roads are wet 8 months out of the year as it is. No problem out here.

Just a word for Oregon... We might not even notice ;) because our roads are wet 8 months out of the year as it is. No problem out here.

We need all the water that we can get!

Joe, drying up in California heat.....:(
and fires!!!!