Text 2184, 116 rader
Skriven 2006-06-08 11:46:00 av Robert E Starr JR (2630.babylon5)
Ärende: Re: Atheists: America's m
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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...

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

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.  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...

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...

Charlie
                                                                               
                       
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