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Electrolysis + fuel cell as ultimate battery.

Discussion in 'Home Power and Microgeneration' started by Pike, Aug 12, 2003.

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  1. Pike

    Pike Guest

    I've been visiting and scanning this group for a couple years now, and
    haven't run across any thing about electrolysing water when there is excess
    power from from PV and wind generation systems. I think this may be a very
    effective high-return form of storage even if you just store the H2 and O2
    in membranes and burn it, perhaps use it for welding, or ultimately for
    powering a fuel-cell, (I don't know if there are any consumer priced fuel
    cells available yet. I imagine that an electrolysis cell would be fairly
    easy to make for a home tinkerer, but a fuel-cell would have to be
    commercially produced, but the thought almost inlimited storage seems quite
    exciting- I realise thought that storing hydrogen in a bag could be
    dangerous and that compression introduces a whole new level of cost, but
    still it seems like the best way to save summer sun for a rainy day. PS. You
    could fill your zeppelin go cruising and then turn it into home power,
    (don't take the kids)
     
  2. ....

    Well, if you have been reading this group for a while then you know that
    PV is one of the very most expensive ways to generate electricity there
    is. Wind is better but at the home size it's still expensive.

    Since these forms of generating electricity are so expensive, it turns
    out that people rarely buy more than they need. Some systems are even
    designed with a gas/diesel/veggie-oil generator to produce enough energy
    for periodic shortfalls.

    So what do people do with their excess power? Well, most of them simply
    don't have excess power. Others adjust their power use based on how much
    they have. I.e. they weld during the summer and watch less TV in the
    winter.

    Have you looked at the numbers of how much H2/O2 you can generate from a
    kWh of electricity? How much the equipment would cost? How much the tank
    for storing it would cost? How much extra power a typical home-power
    setup is going to be generating? Are you so sure it would be worth it?

    Anthony
     
  3. Pike

    Pike Guest

    You're points are well-taken but I still think that hydrogen is a good way
    of storing volatile energy, It is presently a cheap commodity when extracted
    from natural gas, but in closed systems, such as Nasa space vehicles,
    hydrogen and fuel cells were the most elegant and efficient storage mediums
    available. Now I realise that lifting lead acid batteries into earth orbit
    would have been a ridiculous proposition, but now 40 years later I would
    think that this technology is ripe for terrestrial use. I have assumed that
    the conversion from electrical to hydrogen back to electrical is as least as
    efficient as lead-acid storage and I'm looking forward to any further
    insights.
     
  4. Well, my points were simple. It's possible but very, very expensive.
    How expensive? How efficient? I don't know. I haven't done the numbers.
    I suspect that it's so expensive and that only folks like NASA can
    afford to play with the technology.

    It may be lots cheaper simply to buy more lead acid batteries.

    Anthony
     
  5. Murray got that about right, although it seems to me I have heard it to be
    more like 60/40 for electrolysis/fuel cell efficiency. But the advantage of
    the fuel cell is important too. The battery stores all it's energy in the
    lead compounds inside the battery and available for large demands right this
    second, which is great when you start your car, but a real pain when a cell
    shorts out explosively. The fuel cell may be extremely expensive compared to
    the battery for a given load current. But, the fuel cell gas storage, even
    adding something for the tank, is cheaper and a lot lighter for the total
    energy demanded. I had thought there were some large load leveling
    applications that were still trying to figure out how to use fuel cells, but
    where they really shine is where you have very long duration stand alone
    operation at modest power levels. In this case, the battery bank is way too
    expensive, and the fuel storage tank is not forced to be small and portable.
    Space station, perhaps? If you live above the arctic circle and need to use
    solar power for all your needs (as in you are on perma frost and 500 miles
    from the nearest road, power line or gas pipe), you might want a fuel cell
    system. Either that or a couple hundred gallons of fuel oil brought in by
    helicopter.
     
  6. D.A.Kopf

    D.A.Kopf Guest

    A storage battery likes to reach full charge frequently, with the
    disadvantages that the charging efficiency drops and excess generation
    capacity is wasted. In the absence of a reverse feed grid tie, the
    fuel cell could be a competitive dump for excess power and long-term
    storage. It might allow for a smaller battery that would last longer,
    making a hybrid system more efficient overall.
     
  7. Pike

    Pike Guest

    Anthony, GM and Daimler-Chrysler are furiously working on fuel-cell powered
    cars , Even laptop makers are experimenting with methanol-fed fuel cell
    batteries, but if so resigned to lead-acid. Well, then have fun.
     
  8. Pike

    Pike Guest

    Thanks for that insight Murray, I really didn't know that there was that
    much loss (thermal?), guess that pretty much makes cells useless for home
    system storage.
     
  9. Steve Spence

    Steve Spence Guest

    it's cheaper to sell back to the utility. typically there isn't any excess
    .........
     
  10. Guest

    (when you top-post, it makes it impossible to quote your response in
    context. Please consider not doing that.)

    What you read is one person's viewpoint, not necessarily The Way
    Things Really Are. Yes, strictly electric cars aren't profitable
    right now, but the hybrid-electric cars may very well be. Even if
    they're not profitable, we can learn from them & get the experience
    needed to determine if a purely electric car ever will be workable.

    In the meantime, a logical next step might be to go with a biofuel-
    powered hybrid electric car...biodiesel in to the engine, turn
    the generator, drive the car. Gets us going towards less dependance
    on foreign oil, gives our farmers a market for their products, and
    maybe we'll learn how to make an electric car that doesn't need to
    be subsidized in the process.

    Dave Hinz
     
  11. Pike

    Pike Guest

    Another well-informed contribution, but your extreme condescention
    compromises the value of your insights. I hope that this tendency doesn't
    have too negative an effect on your personal life. Good luck.
     
  12. This is a top post. It stands by itself, with any reference a new reader may
    need below (this is technically the same as foot notes and the like in a
    book) Anyone following the thread has already read the prior posts and will
    not appreciate having them over referenced. In this case the post is short,
    and I have not truncated it.

    This is a bottom post. Great for these short epistles where the final EMail
    can stand on it's own.

    I do apologize for being more annoyed by folks leaving long multiple post
    letters above their short replies. I am dyslexic and it is hard enough to
    read without forcing me to scan some vast verbiage I have already read. You
    might recall that a thread is already a history. You do not need to capture
    the thread but merely refer to the prior post (by name of poster, subject,
    or a clip out of the document) and rely on the thread for the rest of the
    details.

    Top, bottom, mid, and no posting is good/bad/indifferent, depending on the
    content of the referenced posts and the post being prepared. I suggest using
    the net to communicate and forget the formal disapproval of top posts. I
    have seen the bottom post abused much worse than the top post.
     
  13. Guest

    Then why did you not trim that which it does not need?
    It's also available using their newsreader.
    Usenet is not a book.
    If it can stand on its own, then there is no need to quote anything for
    context.
    A lot of top-posters lump everything else into bottom-posting, and confuse it
    with "not trimming out anything at all due to lazyness".
    So, is an interspersed response such as this one a problem to read?
    Then why quote at all, let alone on the bottom?
    I could quote articles & RFC's such as http://www.caliburn.nl/topposting.html
    or http://www.cs.tut.fi/~jkorpela/usenet/brox.html which has a bunch more
    links, but it's probably not worth the bother. I think the biggest problem
    with a top-posted message is this: where is one expected to put the
    response to that? On top again, like making a wedding cake upside-down?

    ?yaw taht etirw ot tnaw uoy dluow yhw ,sdrawkcab klat t'nod uoY
     
  14. Strange comments. Ok, I will respond, though I probably should not and will
    I am sure be misunderstood.

    until the following was produced:
    The reference to top post I intended to apply only to the top posted
    portion, not to the rest, and a top post typically includes some "suitable"
    reference, usually excerpted from the prior post or posts. Or did you
    believe that the entire section was unnecessary?
    Oh, but it is. Bundle up the posts, throw out the garbage, and you would
    have a book. A book is a communication device, perhaps one might view it as
    a nonreal time usenet. But I find the carefully thought out presentation of
    ideas to maximize the readers understanding in a book to be extreemly
    instructive for preparation of a series of short discussions on a topic, as
    we encounter here. This is a discussion, and each discussion element has all
    the features of a serial letter, and a letter is a very short book. If it
    works for a book, it should work for a post, for the same reasons. In any
    case, I personally see no reason not to use aspects from the book, or in my
    personal experience, from the scientific paper, to make my posts more
    understandable to the reader. As in poetry, some times you break the hell
    out of the rules to achieve the right effect. You can slavishly follow the
    rules, or seek to be both understood and perhaps entertaining. Purpose over
    form, eh?
    Sorry. The last sentince presumed that you would understand that it
    presented cause and effect. I did not truncate because post short. Or was
    there something else that your "Because?" referes to?
    You are overdrawing the "stand on it's own" concept. A "wrong" comment
    stands on it's own when the context is included. If the relativly short, or
    truncated, prior post or posts provides that context, then it is a part of
    the post and not just a superfluous context. I meant that it stands on it's
    own because the reader will not have to refer to prior letters to understand
    the context. I did not mean to imply that it did not carry any quotations in
    order to achieve that goal. Of course one could summarize the prior context,
    at the risk of putting words in other folks mouths, a favorite of those who
    use polemics to win arguments, but not at all polite.
    I just hate it when I find my screen full of a prior letter with nothing to
    read. So, now if I dare to top post because I prefer to read shorter posts,
    I get the name "top-poster" and the character of confusing bottom posters
    with bottom dwellers? Polemics. Am I a top-poster? This is mid-posted. Is
    that just an anomaly? Do I top post because no one has ever pointed out to
    me that it is bad form? Don't be silly. I just like to top post when I feel
    like it. A top poster could be motivated by lazyness as well as a bottom
    poster, I guess. But if they were, in the one case, I read a line and I am
    done, while in the other case, I read, spin my little mouse buttons, read,
    spin ..., and finally find a word or two, or just give up in disgust.
    Considering the cost, I suggest bottom posting only for very experienced
    posters with a good command of the media.
    Yes. It is very time consuming at my slow rate of recognition. What is
    written had better be good to be worth it. A single word here and there,
    like "wrong", "not even wrong", etc., just wets the apetite and leaves me
    hungry for substance.
    Sequence. When we talk at the cracker barrel, every speaker has a set time
    slot. We all know who said what when. Here, a series of responses may be
    read hours or days out of sequence. You would never puzzle out who I was
    responding to without a reference. I can assume you did read the prior post,
    but I cannot assume you read the one I am responding to imediatly before my
    response.
    Cute. Post on bottom, then post again on bottom. This makes the fresh stuff
    further and further away from where the post opens, unless I write a post
    reader that opens at the bottom? Frankly I think your "biggest problem" with
    top posted is exactly the same as it's best advantage, and your upside down
    wedding cake analogy has no merit. In my, and I expect most folks, readers,
    the top post is on screen when the message is selected. A bottom post
    requires the liberal use of the scroll bar. The wedding cake is right side
    up. The last part assembled is at the top. With bottom posting, you lift the
    cake and insert the new layer at the bottom. You can't tell upside down from
    right side up.
     
  15. Dave, I agree with you completely about the top posting, but after
    reading this thread I found myself singing "The Impossible Dream".

    I'm glad someone's fighting the good fight and, hey, tilting at
    windmills is probably a good cardiovascular workout. <g>

    R,
    Tom Q.


    A: Because it puts the answer before the question.

    Q: Why is it frowned upon?

    A: Top posting.

    Q: What form of posting to newsgroups is generally frowned upon?
     
  16. Guest

    Well, on most technically oriented groups, it's the norm rather than the
    exception, and it's not difficult to impart a clue into the few who don't
    notice that they are doing it. Usually if they actually go read the
    articles, it works. It's kind of a "Oh, of course, why didn't I
    realize that before" when it finally comes to you - speaking from
    experience.
    Yuppers.

    Dave Hinz
     
  17. On the subject of top posting. I do maintain a continuing professional
    communication with customers. I did notice that I very rarely bottom post
    such technical communication. Do you? Why does this not apply to the Net?
     
  18. Guest

    Do you often interact with technical journals? This is a conversation,
    not a book.
    No, but let's go with that. How does contexting work in that,
    er, context?
    Precisely. Lazy. Takes a few seconds per paragraph, though.
    No, again, you're complaining about people who don't bother to trim,
    not about setting a context. Set enough context, not too much, and it
    works great.
    Much of it is a "What the hell is he talking about now?" reaction;
    if there's a sentence or three of context, great. If not, then it's
    a break in reading, go dig down & see what it's about, then back up
    to the comment. Disruptive.
    I wonder if you could use a newsreader that color-codes the included
    quotes by how deep it is? I don't know what OS you're on, but I'm
    sure it's out there.
    How about:

    "Regarding Dr. Phillips' theory of electron hole migration, I have an
    issue regarding his statement about the temperature of the medium being
    unimportant in the rate of migration. Here is my description of how
    this effect is incorrectly described:" etc.

    You set the context, and then add your point, right?
    If one intersperses comments, it's not all at the bottom. If it is,
    it's almost as bad as all on the top, because what of the 17 pages of
    stuff does that paragrah respond to?
    Then I'm done with this topic. If you can't be bothered to spend
    5 minutes on it, I'm wasting my time.
     
  19. Steve Spence

    Steve Spence Guest

    I often lose interest in wading through the previously posted material to
    get to a two line response at the bottom. So I skip the message and go on,
    and your carefully crafted words of wisdom get lost in the ether .....

    Catch me with something interesting in the top 3 sentences, or lose me. The
    background material is below, as my news server expires messages frequently.

    --
    Steve Spence
    www.green-trust.org
    until the following was produced:
     
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