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Energy Storage Problem

Discussion in 'Home Power and Microgeneration' started by Pal, Jan 25, 2006.

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  1. Pal

    Pal Guest

    About 18 months ago, I went as part of a volunteer work party, to one of
    the islands in Vanuatu to help repair cyclone damage to a local high school.

    Shortly before we arrived, their primary energy source (a diesel
    generator) died beyond economic repair. Another group back here in
    Australia started a fund raising effort to get them a new gen set, which
    resulted in a new one being installed about six months ago.

    Problem is, the new one is five or six times the capacity of the old
    one, and their diesel costs have skyrocketed.

    As the school is primarily for teaching boys carpentry skills (although
    they do also have all the general classes one would expect), my
    suggestion was that another fund raising effort should target getting a
    big compressor, and an air storage tank, and a bunch of air driven tools
    for the carpentry workshop, so that their excess electricity generation
    currently being wasted in electric heaters so they don't under-load the
    generator, can be stored for productive use as required. Maybe the
    product of their workshop (furniture or building frames etc.)could even
    be sold to the local community to fund the diesel costs.

    What other suggestions do you guys have? A friend of mine is the
    Director of an Australian overseas aid organisation that has done a lot
    of work in Vanuatu, and I'd love to pass onto him the best of your ideas
    as well as my own...

    By way of background:

    The school has ocean on one side and jungle on the other. The entire
    island is the result of volcanic activity, and the volcanoe is still
    active although quite some distance away (20 miles or so as the crow
    flies). The climate is tropical, mostly moderate, with only a few
    degrees variation between the wet and dry seasons.

    They also have extensive PV lighting that was funded as foreign aid from
    the Japaneese government, but most it doesn't work as there is no local
    servicing capability, and the nearest capable technician to too
    expensive to bring to the island.

    The Vanuatu government pays the teacher's wages, but doesn't provide
    anything for maintenance or infrastructure costs, all of which the
    school has to arrange itself - mostly by foreign donations.


  2. sno

    sno Guest

    Do they have fairly constant wind....waves....??

    Any stream close....??

    Cannot speak to the compressed air idea....

    Do you have any idea of their actual KW usage....??

    With battery storage they could run the generator at maximum efficiency
    to charge the batteries....and then use them to provide the power when
    needed....may be able to run generator few hours each day....

    However batteries are expensive...but maybe you could get them
    and you would need controller, etc......

    The problem with all locations such as you describe it the maintenance/
    upkeep problem....with no one knowledgeable on site, as you mention,
    things tend to break down and not be repaired....

    thank you for listening to my thoughts....sno
    Seen it all, done it all, can't remember most of it

    This tag line is generated by:

    SLTG (Silly Little Tag Generator)
  3. Pal

    Pal Guest

    I only spent a couple of weeks there, but it was fairly calm most of the
    time. Obviously, it does get more blowy from time to time, hence the
    cyclone damage I was there to repair...
    No streams...
    My thoughts were focussed on maximising the usefullnes of what they now
    have rather than replacing it with an alternative. The school's
    (volunteer)maintenance man is trained as a motor mechanic, and so seems
    to be quite competent with the diesel gen set. He had repaired the old
    one many times, but didn't have the equipment to rewind the armature...
    I did have it in my head, but am struggling to remember which cerebral
    file I put it in. :) Not large is the basic answer. While I was there,
    they were using a small portable generator borrowed from a local church
    - I think (may be wrong) it was a 3kW unit(?) at 240v. Their pattern of
    use was to run it for a couple of hours after dusk to drive lighting,
    predominantly of the fluorescent kind. I'd guestimate they had about 50
    38w tubes across the campus. They also ran it during the day when either
    the staff wanted to use office equipment (photocopier and/or a
    computer), or when the computer class was being run (they had 4 pc's -
    around the p3 vintage)
    Your point about the batteries being expensive is right on, especially
    when you add freight, which is a killer on just about everything in
    these remote island communities.
    They do have knowledgable people on site, just not knowledgable in the
    more "High Tech" areas like electronics. Also, to the local mind, paying
    for maintenance is seen as a salesman's attempted dirty trick. In their
    culture, you make something (mostly from bamboo that you get for free
    from the jungle), and use it till it breaks, then make another one! Why
    would you waste time fixing an old one when you can make a new one with
    the same or even less effort?! It's a hard cycle to break.

    In part, that's why I wanted to look at low tech energy storage ideas.

    They have access to just about enough tech savvy to keep the gen set up
    and running (and could probably manage a compressor on the same basis),
    but had problems with the fluro lights - most of which only needed tubes
    and/or starters which they had in their storeroom! PV is clearly beyond
    their skills, and I suspect that battery maintenance wouldn't happen
    either. They have carpentry skills in spades, and enough nouse to figure
    out just about anything that remains in the realms of that which you can
    touch and see.

    Whatever is chosen, I think it has to be physical - like compressed air,
    or water in a header tank (although the only plentiful water is from the
    ocean - full of salt and choral spawn - fresh water is in short supply)

    Thanks for taking the time to think about it...


  4. sno

    sno Guest

    With plentiful bamboo...(dried bamboo has about the same btu
    content as dried oak) might be possible for them to run
    something like a steam generator.....rather then diesel....
    but do not know of any low power units.....would be inexpensive
    to run using bamboo as fuel....and is rather simple tech...your
    diesel mech should/would have no problem understanding....

    I imagine you showed someone how to replace the tubes and starters
    on the not know if there are any good enough led
    lights out their yet that could replace them....their long life could
    be an advantage.....and even with high costs their shipping cost would
    be low.....and would be an almost one time thing....

    thank you for listening to my thoughts.....sno
    Seen it all, done it all, can't remember most of it

    This tag line is generated by:

    SLTG (Silly Little Tag Generator)
  5. RF Dude

    RF Dude Guest

    Folks in this group have mentioned that diesel engines are fairly linear in
    the fuel vs load that they consume. While the "wet-stacking" issue with a
    lightly loaded diesel might eventually bite, I wonder just how often the
    diesel can be loaded up *fully* to keep the issue in check? Certainly
    keeping the diesel genny artificially loaded (partially) with heaters on an
    ongoing basis is wasteful of the fuel and now part of the problem you are
    trying to solve.

    Would the economy of diesel engine size/fuel consumption issue go away if
    they didn't use the heaters but were able to fully load up the genny say
    once per week for an hour?

    RF Dude
  6. Steve Spence

    Steve Spence Guest

    I'm interested in how folks get their diesels to "wet stack". I have a
    68 hp Detroit with a 12.5kw gen head, and typically max out at 8kw
    loads, so I'm well below the magic 40% load number. A prime applicant
    for wet stacking, but have never observed the phenomena ....

    Maybe it's because we use veggie oil and not diesel. There is no
    carbonization on our injectors.
  7. Wet Stacking is more an issue of lack of Engine Operating Tempreture
    than underloading. With the proper thermastats, and effectivly designed
    cooling systems, wet stacking shouldn't be a problem. Ever wonder how
    those diesel trucks can sit idling, at the TruckStops for hours on end
    and not have a problem? It is because they are operating at Designed
    Operating Tempreture.

    Bruce in alaska
  8. Pal

    Pal Guest

    It is pretty much a paradise yes, (but for the mosquitos that give you
    malaria, and the numbalut plant that makes your skin burn if you
    accidentally touch it!) and in spite of the economic limitations, the
    locals are really happy people, and can't do enough for you!

    Only about 5 - 10% of the population of Vanuatu participate in the
    economy at all. Most have their family / village garden in the middle of
    the jungle and grow what ever they need, and trade with surrounding
    villages for whatever they cant grow or make.

    On the outer islands, such as the one where the school is located, there
    are no towns at all, and virtually no employment opportunities (at least
    not in the sence that we would understand them). The school trains boys
    in carpentry because that is the primary skill required in their
    existing village way of life.

    I was one of two electricians in the work party, and we did spend a lot
    of time giving one of the graduating carpenters who showed an interest,
    as much knowledge as we could about electricity while we were there
    (focusing mainly on lighting, since that's what they have). The school
    principle mentioned to us that the student in question was being
    considered for a staff position at the school. Once I got home, I also
    posted him all my old text books on the subject, in the hope that it may
    lead to a new subject of study at the school.

    There are no electrical regulations or licencing requirements outside of
    the two towns (Port Vila, and Loganville), so basically anyone who can
    get hold of a generator can do whatever they like with it. Some of the
    results of this are truely frightening! I thought that if all the
    capenters (who are the only tradespeople most villages would ever see)
    had at least some idea of how to do electrical things safely it would
    have to improve the situation.

    As the economy on the island is based mostly on trade, the stuff they
    could make at the school would have to be traded for whatever the locals
    had in excess, which could then be taken as a bulk lot by some of the
    students to the produce markets in Loganville (on the nearest island)
    where they could be sold, and the cash used to buy whatever they needed.
  9. Pal

    Pal Guest

    Crops (in the commercial sence) are coconut. There are dozens of
    varieties of cocnut, and it is used to produce a dazzling array of
    different produce. Also they grow beef cattle. Beef, Copra (main product
    of coconut), and Tourism are Vanuatu's main income sources.

    As for what CAN grow there, I would be surprised if anything couldn't.
    The soil is so fertile, and the climate so good... I literally saw fence
    posts that had taken root and sent out shoots - No I'm not joking - I
    can post photos if anyone is interested...

    However, as most of Vanuatu is made up of small volcanic islands, there
    are very few "hundred acre" lots that can be used for anything, and all
    of what is, is tied up with strict ownership rules governed by a network
    of village Chiefs who's word is law in their individual domains. Chief's
    will grant rights to garden a small plot of the village's jungle, but
    generally it is intended to support a village resident's family, not
    engage in a commercial activity.

    Biodiesel, sounds like a huge idea though. I know virtually nothing
    about it... Can it be created from any waste crop material? My thinking
    is directed to coconut milk, which is usefull at some points in the
    cocnuts life cycle, but when copra is harvested, is just a waste product...
  10. Pal

    Pal Guest

    I had though of a simmilar idea. Runing power cables from the school
    into the neighbouring village to run some communal lighting in return
    for maybe excess fruit and vegies to feed the students (it is a "live
    in" school). But then, given the skill levels at the moment, perhaps not
    such a good idea - it would be bad form to accidentally electocute an
    upstanding member of a neighbouring community.

    To the best of my knowledge (which is not perfect in this regard) none
    of the local villages have any generators. There is a Hospital a few
    miles away which I would assume has the right generator for its needs,
    there is a Church up the hill that has a small portable generator (the
    one they borrowed while I was there), and the airstip about 30 miles
    away has one to run their radios and the like. That's it so far as I
    know. Even the one and only Restaurant in the local village where our
    entire group had a celebration meal just before we came home, was lit by
    a single hurricane lantern.
  11. Pal

    Pal Guest

    That's what I love about this ng! There is always somebody who knows a
    lot more about any subject than I do.

    If a propper design can eliminate the need to load the gen set up, then
    that could be a fine short term solution to the issue, dropping their
    diesel consumption back to the old levels.

    I will make some enquiries and see if I can get the brand and model, so
    the design can be assessed. Perhaps that "you have to load it up" advise
    they got was generic rather than specific to their case?
  12. Pal

    Pal Guest

    Another excellent question...

    Subject to Bruce's comment in this thread, I would also like an answer
    on this point. It has the potential to make the short term issues
    disappear all together.
  13. Steve Spence

    Steve Spence Guest

    Take a gander at We document our off-grid
    home running a wvo powered generator as our prime power unit.
  14. Steve Spence

    Steve Spence Guest

    It's not the most prolific, and it isn't the best.
  15. Steve Spence

    Steve Spence Guest

    There was no mention of an island in your post.

    Try a little less snipping so folks know what you are talking about.
  16. Pal

    Pal Guest

    Sorry, I'm not sure how I gave the impression that there was electric
    power tools involved. To the best of my knowledge, they have and use
    only manual hand tools.

    My original suggestion was to use excess electricity to compress air -
    with a view to introducing air powered tools to the workshop. This would
    have little benefit in terms of teaching skills with wide application
    (at least in the current situation), but would enable a higher rate of
    production in their workshop, feeding into more product for a new
    cottage industry to fund the diesel in the first place.
  17. Pal

    Pal Guest

    :) This sounds really promising.

    I'll package up all this info I can find on the subject (thanks for the
    links) and get it into the hands of the people who make decisions for
    this community.

    Although, I have no knowledge of them, I believe there are a number of
    other communities around the islands who would also like the idea of
    producing their own bio-diesel...
  18. Pal

    Pal Guest

    The school already takes in students from right across Vanuatu, not just
    the local area. To the best of my knowledge, it is "the" place for
    trainee carpenters who can't afford to study in the capital. Their other
    specialty, is a general office / secretarial course for girls. Both
    courses do include most of the other general subjects one would expect
    of a high school education. The cultural and economic situation in their
    country just means that it is a little more of a blend of what I would
    know as a high school, and a technical college or trade school.

    It is also a residential school. There are four long dormitories (2 for
    boys and 2 for girls). I didn't see inside the girls dorms, but the boys
    were pretty primitive conditions. Both walls were lined with double
    bunks less than an arms length apart, made entirely of bamboo. No
    matresses at all, just woven palm frond bases, and very few had any sort
    of blanket or sheet. A couple had mosqitoe netting but most didn't, and
    since the windows were just open holes in the walls, I have no idea how
    they aviod plagues of malaria.

    Interestingly, during the recent volcanoe alert you may have heard about
    on the world news, the school was housing a large section of the general
    population of the island of Ambae. It was one of two sites deemed safe
    (ie. less risky) by local authorities, and hundreds of village folk
    camped out there until the mountain settled down again. I guess, if the
    volcanoe had blown up, they would have had at least some time to
    evacuate by boat from their location.
  19. Steve Thomas

    Steve Thomas Guest

    If you are thinking of using storage batteries, industrial lift truck
    batteries may be a good choice. It depends on local availability, but
    usually they are cheaper than other deep cycle batteries due to their higher
    volume of production. They are also tough and designed for relatively high
    rates of charge and discharge.
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