Archived posting to the Leica Users Group, 2006/01/30

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Subject: [Leica] RE: LUG Digest, Vol 31, Issue 218
From: william.mattheis at (Mattheis, William G CIV)
Date: Mon Jan 30 10:06:51 2006


On Jan 29, 2006, at 6:31 PM, Dennis Painter wrote:

> Economically viable energy sources may be here sooner than Detroit  
> thinks.

I often wonder where we will obtain the hydrogen required to power a fuel 
cell.  The amount of energy in the universe is fixed.  We can only convert 
it from one form to another.  What will we convert to hydrogen?  Water via 
electrolysis seems to be a good answer, but that requires the input of 
substantial amout of electrical power into the conversion process - - none 
of which are 100% efficient (neither is the operation of a fuel cell).  So 
we will lose energy in the hydrogen generation process, and we wiil lose 
more in the conversion of hydrogen and oxyen to water and electricity in the 
fuel cell - - very clean at the tail pipe, but a little short on efficiency 
with two losses to consider.  We can have a very clean "system" if we 
convert sunlight to generate hydrogen via hydrolysis to power the fuel cell, 
but solar cells require lots of space, are extremely expensive and extremely 
inefficient - - especially on cloudy days.  Oh, and you need lots of water 
for local generation.  So, while Phoenix, AZ would be an ideal locale to 
power solar cells, water may be more scarce that oil as a source of power 
for cars.  Then there is the issue of the energy that must be expended just 
to bottle (under very high pressures) the hydrogen gas generated - - opps, 
there goes some more energy expended.  Then, of course, we have to 
compressing air to collect and bottle the oxygen needed by a fuel cell.  
That will also require significant amounts of energy to power - - where will 
that power come from??  Oh, last best number I heard for solar cell 
conversion efficiency was about 18%, and that is in the latest state of the 
art stuff.  I'd like to see the math that suggests that fuel cells are/can 
be cost competitive with other sources in the near (5 to 10 years) term.  

I am not trying to rain on anyone's parade, but while I can see the fuel 
cell as one means of reducing car generated pollutants, it will not reduce 
our overall use of energy - - just change the form in which we use it.  Of 
course, if we can find a way to do a massive amount of hydrogen generation 
other than the two viable (sort of) processes I am aware of (hydrolysis and 
H+ ion stripping from existing hydrocarbons - - there is that oil and 
natural gas thing again), then we will have a very clean AND EFFICIENT way 
to do motor transportation.

My guess is that we could actually save more oil and reduce pollution faster 
if we just did the work required to make internal combustion engines a lot 
more efficient.  That just requires better heat management technologies like 
ceramic or ceramic coated combustion chambers/exhaust management systems.  
But then, that seems awfully hard when we could just replace piston driven 
internal combustion engines with turbines that (1) run on most anything that 
will burn, (2) do so with a lot fewer parts, (3) have very few repairs, (4) 
are more efficient, and have (5) high operating tempertures that help with 
exhaust issues (particularly unburned hydrocarbons).  Chrysler prototyped 
such a car in the late 1950s/early 1960s (ran 100 test cars around the US 
pretty successfully I believe - - except for some exhaust heat problems like 
scorched paint on tailgating cars I think) - - so it can be done.  Plus, the 
US Navy has clearly demonstrated that jet turbine power ships can be higher 
effective and efficient, and future improvements using a turbine to power an 
electric drive system are on their way.  Gas turbines are also great 
recyclers.  They will burn anything from used peanut oil to fingernail 
polish.  They will burn waste solvents, alcohol made from excess grain 
crops, used oil, l

I guess the path we take depends on what we are trying to achieve, "save 
oil" for the future, or have a cleaner environment by reducing the amount of 
hydrocarbons we burn.  The bottom line is that there is no free lunch.  
There is no such thing as "free energy."  We have to do "work" whether we 
are freeing energy from sources where it is "latent" such as oil, coal, 
hydorgen, etc., or converting it from one form, say sunlight, to another, 
like electricity stored in a battery.  And, as far I know, that work, i.e., 
every conversion process I am aware of, has issues related to efficiency, 
environmental impacts or other costs to society.

Of course, if we could just solve the problem of containing a fusion 
reaction that we have spent zillions of dollars researching we will have 
endless, non-poluting energy.  See, we have known the answer for a very long 
time, we just haven't solved the technical problems yet.  


Replies: Reply from abridge at (Adam Bridge) ([Leica] RE: LUG Digest, Vol 31, Issue 218)
Reply from jcyleung8 at (Joe Leung) ([Leica] RE: LUG Digest, Vol 31, Issue 218)