Re: Atheists: America's most distrusted minority

Josh Hill wrote:
On Tue, 6 Jun 2006 20:34:56 +0000 (UTC), Charlie Edmondson
<edmondson@xxxxxxxx> wrote:


Josh Hill wrote:


We engineers are genuinely excited about it, because it gives every
sign of doing just what it's supposed to -- serve as a pollution-free
energy carrier and a virtually unlimited source of clean nuclear
power.


Hi Josh,
Sorry, you have bought into the hype, not the reality.

Fuel cells ain't cheap, and with the present technologies, never will be. Again, try to actually buy one, esp. one for a vehicle application. If you ain't GM or the government, you ain't gonna even get a call back from the sales agent!


But that's because those fuel cells are still in the laboratory.
They'll have to be mass produced for the price to come down.

To put it in perspective, the fuel cells used by NASA in the 70's cost
about $600,000 per kW. The price of fuel cells today is about $4,500
per kW, a spectacular drop. SECA hopes to bring that down to $400 per
kW by the end of the decade, and according to their website, GE and
Delphi have already brought the costs of the stack down to $294 per kW
and $254 per kW respectively:

http://www.netl.doe.gov/seca/

That's damn cheap! But you can't yet buy one at your local fuel cell
shop.


All these great technology demonstrations, with a range of XXX miles, are mainly marketing speak on those range estimates. The truth is, batteries have a lot better energy storage density than even LH2, and is a whole lot cheaper.


The energy density of compressed H2 and if things pan out metal
hydride storage is sufficient to give a fuel cell car range comparable
to a gasoline vehicle. And fuel cell vehicles can be refilled like a
conventional car, whereas battery-powered vehicles have to be
recharged, which limits their effective range.

Battery technology has been improving slowly in recent years, whereas
fuel cell technology has been improving rapidly. So fuel cells are
expected to become significantly cheaper than batteries within two or
three years. Conversely, batteries are still too heavy and/or
expensive to be the primary power source for a vehicle with the range,
performance, reliability, and cost of a gasoline-powered car: as
things stand, we're a few years away from even a practical plug-in
hybrid. That equation may well change some day, but as things now
stand it seems many years off.

I wouldn't be surprised though if vehicles combine batteries and fuel
cells, though, with the batteries used to store the energy from
regenerative brakes and perhaps for local travel where their
efficiency advantage outweighs their higher capacity cost.

(Another way of looking at it: fuel cells are actually very similar to
batteries, but since the fuel is supplied externally, they need only
be sized to provide x kW, whereas (non-flow) batteries have to sized
to store the energy. So fuel cells have an intrinsic cost advantage,
which depending on specifics may or may not outweigh the efficiency
advantage of batteries.)


And, using a long carbon chains to store the hydrogen is better yet... 8-)


Heh, yes, until the world melts and we get nuked by Iran . . .


And finally, you still gotta get the hydrogen in the first place. If you have electricity from wind, nuke, or any other source, and you want a car, use batteries. You don't want to waste 70% of it creating and using hydrogen.


No, but look at it this way:

Midrange estimate of the cost of a gallon equivalent of hydrogen from
wind: $2.20

Estimate of the cost of a gallon equivalent of off-peak electricity
from a battery charged from the grid (in a plug-in hybrid, but I'll
assume the figure for all-electric cars is similar): $1.00

So the power for the battery option is cheaper -- until you include
the cost of the batteries! When you do, the battery option becomes
more expensive for anything but local travel. (I'm assuming that both
batteries and fuel cell technology continues at its current and
projected rate.) Thus the economics favor the vehicle with a fuel
cell, or, quite likely, a battery and a fuel cell.

Also, the hydrogen could be made more cheaply from natural gas -- I've
chosen the cleanest option, wind and electrolysis. To be truly fair,
one would have to compare wind and electrolysis with wind and
batteries, in which case one has the penalty of grid storage, which
adds to the cost of the electricity.


By the way, all that 'market speak' about fuel cells being more efficient than and ICE are just that, MS (i.e. BS!) They are basically saying "We COULD be that efficient, some day blah blah blah" when in reality, the actual difference, at theoretical best, would be like 2-5%, and the ICEs are getting more efficient a lot faster than the fuel cells are.


Where did you get your figures? I found an article that purported to
minimize the difference:

http://www.evworld.com/view.cfm?section=article&storyid=730

but at a first reading it makes at least two bad assumptions, one by
comparing the highest efficiency ICE's with current fuel cells rather
than those that will be produced, the other by assuming that the H2
will be compressed rather than stored in hydrides.


Now, if you are talking going to high efficiency diesels, you have an argument! You just can't buy them in California... :-(


From what I've been reading, you'll be able to, eventually. And they'd
be great with biodiesel. But I doubt that anyone's going to want to
drive anything with an ICE once fuel cell cars hit the market -- hell,
I suspect that would be true even if the fuel cell vehicles cost more,
because they'll be more comfortable and stylish than anything on the
road and they'll give your old sedan the performance of a Porsche . .
..

Hi Josh,
Guess we will just have to agree to disagree. You have been reading propoganda produced by the proponents for hydrogen, and I have been reading propoganda produced by the opponents, although mine was generally written by engineers with engineering analysis, and the pro-hydrogen pieces are typically written by professional writers speaking to researchers - hype aplenty... 8-)

And, there are theoretical limits on the fuel cells and the electrolysers, which we are a long way from even approaching. When we get close, that will be when the fuel cells are 3-5% better than an ICE. Beware when you hear someone talk about the efficiency of one part of the system, such as just the fuel cell, and compare it to the entire system, such as an ICE. Also, take care when they mention botton cycling, and such 'efficiency boosters' as they will have little place in vehicle applications. That is where you take the waste heat from the unit, and use it for something else. Except for heating your car interior in winter, there is little use for the waste heat in a mobile application.

And take a better look at the reality of those metal hydride storage tanks. The only place I have seriously seen them considered is in a submarine, and even there, it is a demonstation vehicle. They weigh A LOT, don't hold that much hydrogen, require high temperatures to function, and are therefore a nice research project but have little hope of being in your garage!

Also, you spoke of grid storage ADDING to the cost of electricity. Have you seriously priced the alternatives? That $2 a gallon equivalent for wind-h2 is serious fantasy. Really.

Charlie

.

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