[Grovenet] FYI, from this week's E-Skeptic

[David Morelli]

I appreciate the suggestion that we will need to change our  
transportation system.  That will have consequences on our eating  
habits and our residential living patterns, as well as our employment  
patterns.  And we need to start the process because the change will  
come.  Possibly our only option may be to exercise some choice in the  
degree to which we are prepared.
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I have a quibble in the description of Hydrogen as an energy carrier  
not an energy source.  If it is true ( which is a semantic issue )  
then petroleum resources are only "energy carriers" not energy  
sources as well.  The fact that they carry ancient solar energy to  
the present doesn't change the fact that they only contain ancient  
solar energy.  Because it is made about the same time it is consumed,  
hydrogen has the benefit of transparency in the energy carrier  
question, while the time lag between creation and consumption causes  
otherwise well versed people refer to petroleum as an energy source.

Depending upon how the lines are drawn, nuclear energy could be  
called the sole source of energy upon the earth.  Nuclear fission in  
the earth's core for the geothermal sources, and nuclear fusion in  
the sun for the other sources.  Or the lines could be drawn so that  
gravity is the sole source, since it is the force that produces  
tides, generates the pressures necessary for stellar nuclear fusion,  
and it is stellar gravitational collapse that forms the elements that  
are available for nuclear fission.

Hum, shall we call Uranium an energy carrier?  After all, it started  
as hydrogen before gravitational energy created it a few Billion  
years ago.

David

On Mar 16, 2008, at 7:29 PM, Gregory Gritton wrote:

> Hi all,
>
> Many people place a lot of hope in the "Hydrogen economy"
> without realizing what it really is.  The article does well
> to point out that Hydrogen is an energy carrier, not a source,
> and that it isn't a very efficient energy carrier.
>
> However, while the general message of the article makes sense,
> it does contain a number of irrelevancies and at least one
> inaccuracy that make things seem even worse than they are.
>
> The inaccuracy is simple.  The article mentions 220,000 miles
> of natural gas pipelines costing $1 million/mile.
> It gives a figure of $200 trillion or more for duplicating
> that for hydrogen.  But, if you do they math, they are off
> by 3 orders of magnitude.  The cost would be $200 billion.
> (Still a huge sum, but not absolutely impossible.)
> This is the only error I noticed due to the fact that it
> was so glaring, but if there was this one, there may be others.
>
> The irrelevancies are a little trickier.
>
> One common way to rate energy usage is on efficiency.
> This works well for a single energy source.  For example,
> it is valid to compare the efficiency for propelling a car
> of burning oil in an internal combustion engine, like we
> do now, to burning oil in a power plant to generate
> electricity and propelling a car with the electricity,
> or producing hydrogen from oil and propelling the car
> with hydrogen.
>
> Efficiency comparisons work less well when comparing
> different energy sources.  If the sources are fuels
> like oil or coal, there is some sense, since both could
> be burned in similar power plants, that ought to have
> comparable thermal efficiencies.  But, comparing the
> efficiency of burning oil to extracting the energy from
> the wind or the sun is nonsense.  The fact that wind
> turbines are only 30-40% efficient at extracting energy
> from the wind has no relationship too the efficiency
> of burning oil, nor does the 9% efficiency of solar cells.
> Oil is ultimately derived from solar, so one might as
> well compare the efficiency of creating oil from the sun,
> vs. solar panels.  Measured in that way, the solar panels
> are quite a bit more efficient.
>
> While the article exaggerates some of the problems,
> one theme it doesn't discuss much, that it could have,
> is the underlying assumption that we will all continue
> to drive cars in the same way we do now as world oil
> production levels off and then declines.  Switching
> to electric vehicles (or hydrogen powered ones) would
> require a massive increase in our electrical generation
> capacity.
>
> An alternative might be improved public transportation
> networks as exist in Europe, where thousands of miles
> of electrified railroads exist.  Even after accounting
> for electrical generation losses, European railroads
> use less than 1/2 the energy per passenger mail than our
> cars do.  (Raw energy usage is less than 1/6th.)
>
> Developing such a network would require both a significant
> expenditure as well as revising regulations that currently
> prohibit light weight trains in the US.  Even so, it would
> be far smarter than to try to fight over the ever decreasing
> oil reserves that exist in the world, or to pin all our
> hopes on a mythical hydrogen economy.
>
> Sincerely,
>
> Greg Gritton
>
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