[oclug] [OT] Solar / Renewable Power Generation
bb at L8R.net
Mon Aug 12 17:16:19 EDT 2002
On Mon, 12 Aug 2002 15:57:32 -0400 (EDT)
Jon Earle <je_linux at kronos.honk.org> wrote:
> On Mon, 12 Aug 2002, David F. Skoll wrote:
> > On Mon, 12 Aug 2002, Jon Earle wrote:
> > > Without even
> > > figuring all the costs for mounting structures, wiring, inverters,
> > > controllers and anything else I'd need, I think the above would be
> > > horrifying expensive to build.
> > I'm sure I read somewhere it takes several years (maybe 10) for solar
> > cells to generate enough electricity to equal the energy expended to
> > manufacture them. (You have to melt silicon to make solar cells, and
> > that takes lots of heat.) So I'm not sure solar cells are much good.
> > Other alternatives (wind, fuel cells, solar energy via water heating
> > rather than photoelectricity) are probably far more practical.
> Wind is interesting, but from what I've read so far, only about 30-40%
> efficient (I believe the best efficiency that can be realized is 59%).
> Fuel cells are probably going to be the way things are done. And while
> they're nifty, they're just not as fun as a big windmill or a field of
> glittering PV cells. :) I'd still have to buy propane however, which
> means I'm still joined at the hip to an energy company.
Fuel cells are initially designed to run off of hydrogen, not propane.
They can (and are mostly now) be fitted with devices that sift the
hydrogen out of the propane, allowing you to use it for power.
I am not sure why you are staying away from hydrogen as a power system.
Nothing, and I repeat nothing, is more efficient as a battery than
splitting H20, and storing the resulting hydrogen. Ballard fuel cells are
_incredibly_ efficient, with an astonishing 85%+ of the energy being
converted to electricity. Generators and other combustion engines are in
the 10-20% range, with 80% _loss_ to friction and heat.
My understanding is that the Calgary based Xogen should have their all in
one tap_water_to_hydrogen unit available soon. It is designed to work in
the home, plug into a tap, and produces hydrogen when power is applied.
All that is needed at that point is a compressor and a tank to store the
hydrogen. Draw it off as needed, and the fuel cell produces the power.
If you (for some horrible reason) run out of reserves, you can use propane
as a fallback to power your house.
You can use whatever you want to produce the initial power, but unless you
have _some_ sort of battery system, you will be throwing it away.
Batteries are pathetic when it comes to power loss, slow power drain, and
limited capacity. It is conceivable for you to have a large enough
hydrogen tank allowing you to store excess power from solar cells during
the summer, and burn the excess in the winter.
There are lots of sites about the above and I strongly suggest you look at
them. After all, who wants to put together something using 50 year old
technology, that is very lossy and will be replaced by something that is
much more efficient shortly.
As to the aforementioned study named by David, I would be very hesitant to
look at anything negative about alternate power systems. This doesn't
mean it is incorrect, but we are all aware of the intense campaign against
alternate power systems. There are some big bucks involved, which is why
it has taken so long for hydrogen power to get as far as it has. I recall
a similar article, but no math was presented as proof of the findings.
> Interesting point about the manufacture of PV cells... that would help
> explain why they are expensive.
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