Text 2224, 240 rader
Skriven 2006-06-09 15:19:00 av Robert E Starr JR (2670.babylon5)
Ärende: Re: Atheists: America's m
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* * * This message was from Josh Hill to rec.arts.sf.tv.babylon5.m * * *
         * * * and has been forwarded to you by Lord Time * * *         
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On Thu, 8 Jun 2006 16:05:14 +0000 (UTC), Charlie Edmondson
<edmondson@ieee.org> wrote:

>Josh Hill wrote:
>
>
>> Well, here's the source for my figure, an excerpt from an article
>> published in Science by some researchers at Stanford:
>> 
>> "The unsubsidized near-term (<10 years) cost of producing hydrogen
>> from wind is estimated as follows (table S2) [direct electricity from
>> modern wind turbines in the presence of annual winds at speeds of >6.9
>> m/s, present over >20% of the United States]: cost, $0.03 to $0.05 per
>> kilowatt-hour (kWh); transmission cost, $3.45*10^-6 to $1.38*10^-5 per
>> kWh/km; transmission distances, 20 to 1500 km; internal combustion
>> engine efficiency, 0.16; HFCV efficiency, 0.43 to 0.46; electrolyzer
>> cost, $400 to $1000/kW; interest rate, 6 to 8%; electrolyzer energy
>> requirement, 53.4 kWh/kg of H2; fraction of time wind is available to
>> electrolyzer, 0.5 to 0.95; compressor cost, $0.7 to $1.34/kg of H2;
>> and storage cost, $0.31/kg of H2. The total is $3.0 to $7.4/kg of H2,
>> or $1.12 to $3.20/gallon of displaced gasoline/diesel, which compares
>> with the actual costs of U.S. gasoline and diesel in mid-March 2005 of
>> $2.06 and $2.19 respectively. Adding the reduction in health and
>> mortality costs from wind HFCV's of $0.29 to $1.80/gallon, which is
>> the externality cost of gasoline, gives a direct cost plus externality
>> cost of U.S. gasoline/diesel of $2.35 to $3.99/gallon, which exceeds
>> the mean cost of hydrogen from wind ($2.16/gallon) even if retail
>> hydrogen is marked up."
>> 
>> http://www.stanford.edu/~wcolella/pubs/SciencePubHyd.pdf
>> 
>> I haven't checked all the figures, but the ones with which I'm
>> familiar, e.g., the current cost of wind, seem accurate, and their
>> results seem consistent with the back-of-the-envelope calculations I
>> did a few years back.
>> 
>> And another source I've referred to (the table is much clearer in the
>> original and it has some interesting info in general, so you may want
>> to go to the URL rather than try to figure out my kludgey
>> transcription):
>> 
>> A. Current Technology with Grid Backup
>> A. Current Technology No Grid Backup
>> C. Future Technology with Grid Backup
>> D. Future Technology No Grid Backup
>>  
>> Average cost of electricity (cents/kWh)
>> 
>> A     6
>> B     6
>> C     4
>> D     4
>>  
>> Wind turbine capacity factor (%)
>> 
>> A     30
>> B     30
>> C     40
>> D     40
>>  
>> Hydrogen ($/kg)
>> 
>> A     6.64
>> B     10.69
>> C     3.38
>> D     2.86
>>  
>> Carbon emissions (kg C/kg H2)
>> 
>> A     3.35
>> B     0
>> C     2.48
>> D     0
>>  
>> http://darwin.nap.edu/books/0309091632/html/228.html
>> 
>> This last source appears to significantly overstate the cost of wind
>> using current technology, BTW: 3-5 cents/kW-hr is the figure I usually
>> see for current turbines, not the 4-5 cents they're assuming. And they
>> seem to be presupposing a lower capacity factor.
>> 
>> Care to poke holes in these figures?
>> 
>Would love to.  Unfortunately the first link is now to a pollution 
>reduction document, not a hydrogen production document, so I will have 
>to work from the figures you gave...
>
>First, ICE efficiencies are in the 30% range...

True, at least if we're talking about new vehicles.

>They found a source of really cheap electolysers, and some surplus 
>pressure tanks to store their hydrogen in.  NASA have a surplus sale?

I'd say it's a given that the price of electrolysis equipment will
drop with R&D and high production levels. It's been a low-demand
specialty item.

>Ok, so they took the low ICE efficiency, and the theoretically good HFC, 
>to get their $7 kg of H2 to be equal to three gallons of gasoline. 
>Usual conparison I have seen is 1 kg H2 roughly equal (in ideal 
>circumstances) to 1 gallon gas.

I've seen the same estimate, but I've no idea where it comes from or
how valid it is. Assuming for the moment that it's valid, it would
yield a near-term price for a gallon equivalent of H2 of $3.00 to
$7.50. Add the estimated externality cost of gasoline, $0.29 to
$1.80/gallon, to the current price of gasoline and one gets $3.18 to
$4.69. So even with the pessimistic efficiency figures, we aren't
really out of the ballpark.

And there are many opportunities to cut the cost, some of them, like
reductions in the cost of electrolysis, mentioned in my second
reference. For example, a plug-in hybrid fuel cell vehicle could on
average derive more than half of its energy directly from the power
grid, lowering the price of fuel to approximately ($1.00 + $7.50) / 2
= $4.25 per gallon equivalent worst case and ($1.00 + $4.00) /2 =
$2.50 best.

I'm not suggesting that this will happen, just that there's plenty of
wiggle room to bring down the effective cost of clean hydrogen. The
estimates in the second source suggest that the cost could drop as low
as $2.86/kg for H2 from wind, which would be cheaper than the actual
cost of burning gasoline.

>Other than those fudges, a reasonable 
>estimate of what it could cost. Still assumes you can get those cheap 
>fuel cells and electrolysers that someone should start building Real 
>Soon Now...

Not something I'd worry about, since the cost of fuel cells has been
plummeting. Laboratory prototypes are already almost cheap enough in
mass production, and in a couple of years they will be. Think LCD's.

>Sorry Josh, it is another academic exercise where, when I get to set the 
>conditions, I get the conclusions I want.  When I start seeing permit 
>requests for the H2 generation stations here in DHS, I will believe this 
>has a future.  When I see GM or Volvo or ANYONE announcing in THIS YEARS 
>car lineup an H2 fuel cell car, I will believe it.  Until then, it is 
>all marketing speak and PR.  I am sorry you are so gullible...

We engineers are a funny bunch, convinced that we can do in one year
what takes three when we're working on something ourselves, convinced
that it will take thirty years to do what takes one when we're not.

For example, I remember vividly a panel discussion at the Audio
Engineering Society about the applicability of the then-new laser
videodisk recording technology to audio. To a man, the experts thought
it would have none. "I suppose you could record 24 hours of music,"
said one guy.

A year later, Sony and Philips introduced the Compact Disk.

I've seen this again and again.

There were the arguments I had a few years later with film guys in the
early days of HDTV research: "HDTV will replace film." "No,
impossible, it will never happen."

Then there was the time I was on a panel myself during the drive to
upgrade NTSC and suggested that it might make sense to replace analog
broadcast TV with an all-digital system based on teleconferencing
technology. Stunned silence ensues. Then, about a year later, General
Instruments submits a proposal to the FCC that does exactly that, uses
Huffman coding, DCT, and the like for over-the-air digital
transmission, and it becomes the basis of our current broadcast
system.

Or all those debates with the mainframe guys 20 years ago: "The PC
will replace the mainframe in all but a few applications." "Nah,
impossible."

You say you want to see permit requests for H2 generating stations and
that you want to see the cars available before you believe it's
practical. But from what I seen, commercialization often lags behind
the R&D effort by many years and so doesn't have much predictive
utility.

Forex, Blumlein was making stereo motion picture soundtracks in the
1930's and Bell Labs 33 RPM, 45-45 groove electrical stereo recordings
stamped on vinyl, but the public was still playing shellac 78's with
cactus needles. The LP wasn't introduced to the public until IIRC
1948, and the stereo LP until IIRC 1958, and the stereo movie until
perhaps 1972, 40 years later.

At the opposite extreme, a technical paradigm shift things can move so
rapidly from the laboratory to production that there's practically no
warning. So commercialization isn't a very good guide in that case
either.

What you can do I've found is look at the current state of technology,
the rapidity with which improvements are being made, and the
theoretical impediments, if any, to the goal. Laboratory developments
that represent a paradigm shift tend to proceed rapidly at about the
time of the shift. After that, progress slows down, becomes asymptotic
with regard to the theoretical limits.

I feel confident that I can predict with a more than fair chance of
being right that the reduction in the price of fuel cells will
continue to the point at which they're cost-competitive with gasoline
engines. Why? Because there's no theoretical impediment to it, because
we're much earlier in the research curve than we are with batteries --
fuel cells were invented in the 19th century, but it's only in recent
years that significant sums have been invested in their development --
and mostly because we're only a hair's breath away from achieving the
goal, after having made geometric progress over a number of years. To
think otherwise in the absence of a fundamental limit (the amount of
precious metal required, say) would be like saying that the price of
LCD's won't continue to drop.

And everything else pretty much follows from economical fuel cells.
With the exception of the storage problem, the other impediments to
FCV development are pretty trivial. And as far as I can tell, hydride
storage isn't as far from practicality as you suggest -- more like a
tough but doable R&D push. I can't be sure of that, of course, but
even if it hit basic limits, hydride storage isn't critical path, just
a highly desirable way to avoid range or design compromises.

So my sense is that we're much where we were with respect to FCV's
that light bulb researchers were back in the days when they were
looking for alternatives to platinum filaments and about to discover
carbonized thread. Which is to say somewhere between good and great. I
can't prove it, of course, but I've found that this sort of assessment
has worked pretty well in the past.

-- 
Josh

"I'm not going to play like I've been a person who's spent hours involved with
foreign policy.
I am who I am." - George W. Bush
                                                                            
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