Re: Solar-hydrogen home power system?

From: Ray Drouillard (cosmicpam2_at_comcast.net)
Date: 10/21/04 

Date: Thu, 21 Oct 2004 00:22:27 -0400

In what way? Because I don't believe that hydrogen is economically
feasible right now? If you look at the top of the thread, you'll see
that my first post said exactly that.

I may agree with the conclusion, but I see a whole lot of bad science
used to prove the point. I am trying to correct the bad science. The
biggest blooper is the one where someone equated a hydrogen chemical
explosion with an H-bomb. That was a real howler.

Ray Drouillard

"Gymmy Bob" <nospamming@bite.me> wrote in message
news:jeGdnT953d4RkurcRVn-hA@golden.net...
> Sounds like a backpaddle for the "speak too soon foolish"
>
> "Ray Drouillard" <cosmicpam2@comcast.net> wrote in message
> news:2tofefF21iggsU1@uni-berlin.de...
> >
> > "Dan Bloomquist" <EXTRApublic21@lakeweb.com> wrote in message
> > news:4176DEE2.2040003@lakeweb.com...
> > >
> > >
> > > Ray Drouillard wrote:
> > > >
> > > >
> > > > 40% Is a whole lot better than the "less than none" that Don
> > Lancaster
> > > > keeps quoting. As a matter of fact, I'm beginning to believe
that
> > he
> > > > has the whole spiel stuck in a text file for quick addition to
his
> > > > prose.
> > >
> > > Capital cost needs to be considered. On the other hand, Mr.
Lancaster
> > > has wave his hands around about wind and PV being energy sinks.
Past
> > > research has shown otherwise.
> >
> > Capital cost is economics, not engineering.
> >
> > Effeciency is engineering, not economics.
> >
> > They can be related, but the person expressing that relationship
needs
> > to be explicit.
> >
> >
> > >
> > > I went and fetched Grahams post for you:
> > > > > This is it:
> > > > > 41 percent (of delta 'G' of hydrogen oxidation to water
vapour)
> > > > > for the fuel cell spec'd at
> > > > > http://www.ballard.com/resources/powergen/NexaSpec***.pdf .
> > > > >
> > > > > Raising specific power -- only 1.2 kW over 13 kg --
> > > > > to levels adequate for a car prime mover drops the
efficiency,
> > > > > I guess, by a third. Then there are inverter and motor
losses,
> > > > > and we're down to 20 percent.
> > >
> > > However, I don't agree to his 50% hit in the implementation. The
EV
> > side
> > > of the power train can easily do 85-90% net. There are source to
wheel
> > > traction systems that run 90% to 97% over most of thier
power/speed
> > range.
> >
> > Agreed.
> >
> > With 65%+ efficient fuel cells, and 90%+ motors, a vehicle can turn
> > hydrogen into motion very efficiently. The main bugaboo is storing
the
> > stuff (an issue that has been debated hotly in this thread).
> >
> > There are now 60%+ efficient methane-fuelled fuel cells. I know of
none
> > that are commercially available, unfortunately. If they do become
> > available, they would be ideal for running an ev because the methane
> > storage technology already exists. It still isn't as energy dense
as
> > gasoline, but it's a lot more dense than hydrogen. It also has the
safe
> > ty advantage of dissapating and floating away in the unlikely event
of a
> > pressure tank rupture.
> >
> > Thirdly, it's a real fuel -- not something that is derived from a
fuel.
> > It can be mined, or very easily created from biomass.
> >
> >
> > >
> > > >
> > > > I still want more details about that 40%. I'm hearing figures
> > anywhere
> > > > between 60% and 90% for both electrolysis and fuel cells. Where
is
> > the
> > > > hard data?
> > >
> > > Crunch the numbers for your self, on that PDF above for that
mighty
> > > pricey PEM unit, if you don't believe Graham.
> > >
> > > > Yes, I can google until I'm blue in the face and crippled
> > > > from carpel tunnels, but some of those quoting the efficiencies
> > ought to
> > > > have real data somewhere.
> > > >
> > > > If we have electrolysis going at 80% efficiency, and a 70%
efficient
> > > > fuel cell (just to throw in some reasonable numbers). you have a
> > total
> > > > efficiency of better than 50% (allowing for some modest storage
> > losses).
> > >
> > > Electricity to wheels. Electrolysis 80%, storage 90%, PEM 40%,
vehicle
> > > 85%. So you net 25% of your electrical input. There are EVs in
> > > production that net better than 50% now. Also, compare the capital
> > cost.
> > > Hydrogen, rough guess, will run some 5 to 8 times an EV commuter.
> >
> > It pretty well goes without saying that making hydrogen from grid
> > electricity is a no-win situation.
> >
> > As far as comparing a hydrogen system to a battery system -- well, I
> > expect the battery system to win when you consider efficiency. The
> > biggest obstacle for EV transportation is the lousy range of even
the
> > best vehicle. It would be worth it to some people to give up some
> > efficiency just to get more range.
> >
> > Getting back to the original post, though -- he was talking about a
> > totally fixed application. The electricity --> hydrogen -->
electricity
> > idea had occurred to me, too. I was pondering what to do with cheap
> > solar cells of those much-promised organic semiconductor cells
become
> > available at a reasonable price. At the time, I lived in the city,
and
> > was limited to the area of my (small) roof. Therefore, storage to
pick
> > up the slack in the winter would be a necessity. Since we also had
> > natural gas piped in, I planned on generating any additional
electricity
> > needed using a natural gas fuel cell. The waste heat would be used
to
> > heat the house.
> >
> > Now that we live on a nice ten acre parcel, I'm not nearly so
limited
> > when it comes to the area that I can cover with solar cells. That
makes
> > it more feasible to get enough area covered to produce a day's worth
of
> > electricity on even the shortest day. That cuts the storage
> > requirements considerably -- both in quantity and time. Hydrogen
> > wouldn't be necessary at all.
> >
> > Of course, all of the above depends greatly upon the much-promised
cheap
> > solar cells, as well as the availability of relatively inexpensive
fuel
> > cells.
> >
> > Then, of course, there are things like inverters and/or DC
appliances.
> > The ceiling fans would have to be ripped out and sold. I would also
> > have to find something to replace the compact fluorescent lamps that
we
> > have used to replace almost every incandescent light in the house.
I
> > would probably use regular red, yellow, green, and blue LEDs in
fixtures
> > that allow the light to mix because that is more efficient than
using
> > white LEDs (for very good quantum physics reasons).
> >
> > Incidentally, the cheapest way to save energy right now is to
replace
> > all your incandescent lights with fluorescent lighting. Soon, LED
> > lighting will be more available.
> >
> > So, my next realistic step is to make a digester to turn organic
garbage
> > into methane. I don't expect to find an affordable methane fuel
cell
> > any time soon, so if I get more methane than I can burn in my
appliances
> > and vehicles, I'll use it to fuel a standard CNG generater, and use
the
> > waste heat to heat the house. Lots of research has to be done
before
> > getting anywhere near that far, though.
> >
> >
> >
> > >
> > > >
> > > > If you want to compress the hydrogen to store it, and if the
energy
> > cost
> > > > of that is significant, you can recover some of the energy by
using
> > an
> > > > 'air engine' to decompress the hydrogen before it is fed into
the
> > fuel
> > > > cell.
> > >
> > > Capital cost and energy density.
> > >
> > > >
> > > > Also, in a solar energy system, you are going to be getting more
> > energy
> > > > in the summer than in the winter. That means that you will be
using
> > the
> > > > fuel cell in the winter if your solar array is sized such that
you
> > need
> > > > to store power in the summer for use in the winter. In that
case,
> > the
> > > > heat that is generated by the fuel cell can be used to heat the
> > house.
> > > > In that way, you can use 100% of the energy that you have stored
in
> > your
> > > > hydrogen tanks. Any inefficiencies end up heating the house, or
> > maybe
> > > > even cooking the meals (depending on how 'retentive' you want to
be
> > when
> > > > designing the system)
> > >
> > > It will never ever make sense to use hydrogen in a terrestrial
> > > application. Just run some numbers and compare them to the
> > alternatives
> > > that are presently applied.
> >
> > I won't argue that point. Before I buy the equipment needed to
> > generate, store, and use hydrogen, I will build a big water tower
and
> > use my excess energy to pump the water uphill, and use a turbine or
> > water wheel to get the energy back. As a bonus, I'll also have
either a
> > swimming pool or a fishing pond.
> >
> > I might argue with the people who are scared to death of hydrogen,
or
> > those who say "less than zero", but I have already throught through
the
> > hydrogen-as-a-fuel situation to have a good handle on what it would
take
> > to make that practical. On a large scale, off-shore nuclear energy
> > would make it a good option. On a small scale, it would take a very
> > specific set of conditions to make it worthwhile.
> >
> >
> > >
> > > >
> > > > Certainly, the cost of photovoltaics makes the system
uneconomical
> > now.
> > > > But, this is rec.arts.sf.science, so speculation of future
advances
> > in
> > > > the art are definitely on topic.
> > >
> > > Sure, we could see thin film at a buck a watt. Still not cheap.
I've
> > > been reading about it for years and I still don't see it
happening.
> >
> > I'm talking about organic semiconductors, which may very well be
made
> > very cheaply. Still, I'll believe it when I see it. I'm hopeful,
but
> > far from convinced.
> >
> >
> >
> > > > If I could go out and buy a bunch of plastic sheeting that
converts
> > > > light into electricity with an efficiency of about 8% for a few
> > cents a
> > > > watt, what would I do with it? Putting it on the roof would be
a
> > good
> > > > start. Storing power in batteries short-term for use at night
would
> > > > also be a good idea. In fact, I can save on the cost of an
inverter
> > if
> > > > I use a bunch of batteries in series and store it at 180V, then
just
> > use
> > > > some MOSFETs to generate a pseudo sine wave output -- no
> > up-converting
> > > > switching regulator, no muss, no fuss.
> > >
> > > As a past poster would say, 'If we only had some ham, we could
have
> > ham
> > > and eggs, if we only had some eggs...'
> > >
> > > Inverters are $.50/watt, off the shelf. No muss, no fuss.
> >
> > They will probably be cheaper once electric cars come more into
> > production. Right now, high-power switching transistors and fast
> > high-power diodes keep the prices up.
> >
> > >
> > > Qusetion, why hydrogen?
> >
> > Because it's cool?
> >
> > Remember, I'm not advocating the hydrogen solution. I have thought
it
> > through, and share the conclusion of some or the people I am arguing
> > with. I don't share their reasoning, however.
> >
> >
> > Ray Drouillard
> >
> >
> >
> > >
> > > >
> > > > Ray Drouillard
> > >
> > > Best, Dan.
> > >
> > > --
> > > http://lakeweb.net
> > > http://ReserveAnalyst.com
> > > No EXTRA stuff for email.
> > >
> >
> >
>
>