1. Joined
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    11 Oct '08 15:592 edits
    I have only just found out about a new type of battery which is a "sodium sulphur battery"(which I certainly never heard of before despite successfully completing a C&G in electronics) that could overcome one of the main problems with renewable energy such as wind and solar because it is a very compact way of storing a huge amount of energy. If you just put “sodium sulphur battery” into Google you will get several websites about it including:

    http://www.usatoday.com/tech/products/environment/2007-07-04-sodium-battery_N.htm

    http://thefraserdomain.typepad.com/energy/2008/03/sodium-sulfite.html

    And:

    http://www.mpoweruk.com/high_temp.htm

    Where it states these huge advantages of using this type of battery:

    “Since the mid 1960s much development work has been undertaken on batteries using Sodium for the negative electrodes. Sodium is attractive because of its high reduction potential of -2.71 Volts, its low weight, its non toxic nature, its relative abundance and ready availability and its low cost. All these factors offer the prospect of batteries with very high power and energy densities.”

    -but it also states a small catch:

    “Unfortunately in order to construct practical batteries using sodium electrodes, the sodium must be used in liquid form. Since the melting point of sodium is 98 °C this means that sodium based batteries must operate at high temperatures, typically in excess of 270 °C. This in turn brings problems of thermal management and safety and places more stringent requirements on the rest of the battery components.”

    -never the less, unless I am missing something here, I think this is still an extremely promising development!

    I think I have just become a "sodium sulphur battery fan"! 🙂
  2. Subscribersonhouse
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    11 Oct '08 16:52
    Originally posted by Andrew Hamilton
    I have only just found out about a new type of battery which is a "sodium sulphur battery"(which I certainly never heard of before despite successfully completing a C&G in electronics) that could overcome one of the main problems with renewable energy such as wind and solar because it is a very compact way of storing a huge amount of energy. If you j ...[text shortened]... mely promising development!

    I think I have just become a "sodium sulphur battery fan"! 🙂
    Did you run the numbers? 20 units capable of giving 50 Kw for 6 hours or so, and those 20 are the size of TWO SEMI TRAILERS full. So 10 is one trailer full, and the 20 weigh 60 TONS, ten come in at 30 tons so ONE comes in at 6,000 pounds. I don't know what kind of vehicle it could supply at that rate if you are thinking car. It doesn't sound particularly any more energy intensive than lead acid. If you could get that down to 600 pounds and still have 50 Kw for 6 hours you could have a fully powered car driving at least 360 miles but at 6000 pounds, it is only useful for substations.
  3. Subscribersonhouse
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    11 Oct '08 18:27
    Originally posted by sonhouse
    Did you run the numbers? 20 units capable of giving 50 Kw for 6 hours or so, and those 20 are the size of TWO SEMI TRAILERS full. So 10 is one trailer full, and the 20 weigh 60 TONS, ten come in at 30 tons so ONE comes in at 6,000 pounds. I don't know what kind of vehicle it could supply at that rate if you are thinking car. It doesn't sound particularly an ...[text shortened]... powered car driving at least 360 miles but at 6000 pounds, it is only useful for substations.
    I was thinking about that, suppose for some unknown reason you built a car with a 6000 pound capable tank. First you have one with a sulpher battery and it gives 50 Kw for 6 or 7 hours, enough to go from Philly to Boston maybe. Now suppose you substitute that batter with plain old gasoline or diesel. How many miles would you get out of that? I would use the old adage, a pint's a pound the world around. So 8 pounds roughly is a gallon. So 8000 pounds would be 1000 gallons give or take and 6000 pounds would be 3/4ths of that so 750 gallons. Now my van gets about 18 mpg and hold about 16 gallons so I get about 260 odd miles per tank.
    So 160 gallons gives me 2600 miles, 1600 gallons 26,000 miles, half of that is 800 gallons so about 12,000 miles or so per 750 gallons for my van. Now some cars get three times that gas milage so maybe that 750 gallons will take some cars 25000 miles or more. Sounds like they need to do a little more homework to get that ratio up a bit. Right now it's about 70 to one or thereabouts in favor of gasoline, just taking driving miles into account. Not talking about environmental effects, just straight miles per tank/pound.
  4. Joined
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    11 Oct '08 19:32
    Originally posted by sonhouse
    Did you run the numbers? 20 units capable of giving 50 Kw for 6 hours or so, and those 20 are the size of TWO SEMI TRAILERS full. So 10 is one trailer full, and the 20 weigh 60 TONS, ten come in at 30 tons so ONE comes in at 6,000 pounds. I don't know what kind of vehicle it could supply at that rate if you are thinking car. It doesn't sound particularly an ...[text shortened]... powered car driving at least 360 miles but at 6000 pounds, it is only useful for substations.
    …I don't know what kind of vehicle it could supply at that rate if you are thinking car..….

    You misunderstand -neither I nor anyone else as far as I am aware is proposing to use it to power vehicles! -the idea here is to just use it to store energy from renewables for the mains electric supply (the national grid) -sorry, I should have made that clear in my first post.

    -I think even this battery might be rather impractical for vehicles -not least because all that sulphur in the battery would have to be first heated up to over 200C even before you can even start to get it going! (that would take extra time and energy) -but at least storing all the energy for mains electric from only renewables would be a huge improvement!

    -having said that, it has just occurred to me that it could be used for the very large but slow moving cargo ships -I am guessing the high weight-to-power ratio would probably not pose a significant problem there.
  5. Subscribersonhouse
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    11 Oct '08 21:45
    Originally posted by Andrew Hamilton
    [b]…I don't know what kind of vehicle it could supply at that rate if you are thinking car..….

    You misunderstand -neither I nor anyone else as far as I am aware is proposing to use it to power vehicles! -the idea here is to just use it to store energy from renewables for the mains electric supply (the national grid) -sorry, I should have made ...[text shortened]... am guessing the high weight-to-power ratio would probably not pose a significant problem there.[/b]
    But look at the numbers I just generated, even on a ship, the amount of energy stored per pound or per cubic foot is something like 70 times greater for diesel or gasoline so I don't think we will be seeing them in ships any time soon. Also think about the pollution problem of a crackup at sea, 200 degree C suphur spilling out of a battery the size of semitrucks...
  6. Joined
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    12 Oct '08 08:411 edit
    Originally posted by sonhouse
    But look at the numbers I just generated, even on a ship, the amount of energy stored per pound or per cubic foot is something like 70 times greater for diesel or gasoline so I don't think we will be seeing them in ships any time soon. Also think about the pollution problem of a crackup at sea, 200 degree C suphur spilling out of a battery the size of semitrucks...
    Even if you are right in thinking it isn’t practical for ships (and I am not saying your are not) -these batteries would still be the practical answer for storage of energy from renewables for the mains electric supply allowing perhaps 100% of the electricity for the mains electricity to come from renewables!
    -this would be a wonderful and huge step forward -don’t you think?
  7. Subscribersonhouse
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    12 Oct '08 13:172 edits
    Originally posted by Andrew Hamilton
    Even if you are right in thinking it isn’t practical for ships (and I am not saying your are not) -these batteries would still be the practical answer for storage of energy from renewables for the mains electric supply allowing perhaps 100% of the electricity for the mains electricity to come from renewables!
    -this would be a wonderful and huge step forward -don’t you think?
    u
    Well it could be, for that use, but the bottom line may come a few years down the line when they find out how reliable such a system is overall. For instance, if some contamination issue causes say, aluminum, or something to start plating out in the wrong place, it can ruin it, and there may be issues with the maximum # of charge/discharge cycles. It's just that any new technology has to be tested to find the weak spots as well as the strong points. Which is not to say this is a good technology, it's just that a lot of newly minted technologies ends up with a soft underbelly of hidden failure modes.
    There are other technologies each with its own strengths and weaknesses. Flywheel storage, for instance. It is a matter of how strong can you make the flywheel, and newer carbon nanotube fibers are theoretically 100 times stronger than steel. Right now flywheels are good enough to run some busses. The idea is to put a well balanced, VERY well balanced, flywheel supported by a magnetic bearing in a vacuum where external magnetic fields penetrate the housing and cause it to spin up but it can go from a motor mode to a generator mode with the flip of a switch or controlling electronics. The nice thing about that technology is there are no nasty chemicals involved, it can run at room temperature or high temps or low temps, pretty much temperature independent up to a point and very simple mechanically, one moving part. I think if you got a bunch of them, say each one a meter by a meter by half meter high, just a number off the top of my head, for each one, you can see if you filled that aforementioned two trailers full, you may have at least the same amount of energy storage and no pollution problems. I am not specifically pushing for that technology, no axe to grind there, just pointing out there are other ways to go to get the same results. Right now, the flywheel technology has advanced to the point where a wheel about half to a meter in diameter can be kept in one piece even though it is spinning at 100,000+ RPM. I think they are pushing to get the max up to 500,000 RPM, all things being equal, it stores energy at the square of the RPM's so 500 K V 100 K would give the 500K version 25 times the energy storage density of the 100K version so you can see the potential for improvement to be made there. Going for more modest improvements, say from 100 K to 110 K gives you not 10% improvement but 20%. Going to 200 K gives not twice the capacity but 4 times the capacity and so forth so it's a technology with a lot of promise.
  8. Joined
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    12 Oct '08 15:591 edit
    Originally posted by sonhouse
    Well it could be, for that use, but the bottom line may come a few years down the line when they find out how reliable such a system is overall. For instance, if some contamination issue causes say, aluminum, or something to start plating out in the wrong place, it can ruin it, and there may be issues with the maximum # of charge/discharge cycles. It's just e capacity but 4 times the capacity and so forth so it's a technology with a lot of promise.
    …Well it could be, for that use, but the bottom line may come a few years down the line when they find out how reliable such a system is overall.
    .. .….


    But they have been researching it from the 1960’s (and surely that means they must have been testing it for some time now) and they started using it right now!

    … For instance, if some contamination issue causes say, aluminium, or something to start plating out in the wrong place, it can ruin it, and there may be issues with the maximum # of charge/discharge cycles. It's just that any new technology has to be tested to find the weak spots as well as the strong points.
    ..….


    But surely they have been testing it for some time now -after all, they have already been manufacturing some WORKING sodium-sulphur batteries for some time now -have you seen the picture of the giant one at:
    http://www.usatoday.com/tech/products/environment/2007-07-04-sodium-battery_N.htm ?


    …flywheel supported by a magnetic bearing in a vacuum where external magnetic fields penetrate the housing and cause it to spin up but it can go from a motor mode to a generator mode with the flip of a switch or controlling electronics. The nice thing about that technology is there are no nasty chemicals involved,


    I agree that is a major advantage and I think flywheel storage will definitely also be one of the answer some day in the future -but sulphur is also non-toxic and, although there are obvious safety issues with the hot-sulphur there are also safety issues with the flywheel storage -suppose there is a mechanical failure while the flywheel is fully charged -perhaps as a result of an accident such as something hitting it or violently jolting it -all that tremendous energy stored as angular momentum would suddenly be released with broken fragments flying all over the place at high velocities with potential deadly effect! -don’t get me wrong, I think that risk can be reasonably managed just like with that of the hot-sulphur.

    Now don’t get me wrong, I am all for flywheel research and development -especially as, as I understand it, there have been some significant improvements in the technology recently. But, right now, as I understand it, those advanced flywheels don’t come cheap which is why I guess industry isn’t apparently showing any rush or enthusiasm right now to store energy for the mains electric grid using flywheels. But, on the other hand, it is my understanding that sodium-sulphur batteries are not only cheap but available virtually NOW! -so that research and development has basically beaten the research and development into flywheels to store energy for the mains electric grid and should be available very much sooner which is why I am so enthusiastic about sodium-sulphur batteries (even though they are not perfect) for time is off the essence here because we really urgently need economically viable answers NOW to reduce our dependency on fossil fuels (even if those answers are far from perfect) and not, say, in 30 or 40 years time -at least that is the way I see things.
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    12 Oct '08 16:22
    I just noticed somebody had posted this comment at:
    http://www.usatoday.com/tech/products/environment/2007-07-04-sodium-battery_N.htm

    “Energy storage is an important tool in the utilities toolbox. In addition to the NGK and compressed air experiments, VRB Power Systems has a large energy storage device based on "flow battery" technology. The system is fully proven and commercial, with an installation in PacifiCorp territory since 2003, many installations in Japan, and a planed 2 MW, 6 hour storage facility planned at a windfarm in Ireland. The technology is much less expensive than sodium sulphur - about $400 to $600 per kWhr - does not require the extensive engineering for safety of the NaS, and has a proven longer life with many more charge cycles and a bit better efficiency.”

    Note the “The technology is much less expensive than sodium sulphur” part -that is the bit that I am most interested in although there are obvious other parts of interest there. I tried to find other websites that would confirm this but so far I have failed -can anyone give me a link that would give confirmation of what this person is saying?
  10. Subscribersonhouse
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    12 Oct '08 18:19
    Originally posted by Andrew Hamilton
    I just noticed somebody had posted this comment at:
    http://www.usatoday.com/tech/products/environment/2007-07-04-sodium-battery_N.htm

    “Energy storage is an important tool in the utilities toolbox. In addition to the NGK and compressed air experiments, VRB Power Systems has a large energy storage device based on "flow battery" technology. The syst ...[text shortened]... failed -can anyone give me a link that would give confirmation of what this person is saying?
    V
    When it uses actual figures, you can do some arithmetic. They didn't say how much sulphur costs, the whole battery, it looks like the 50 Kw unit will provide 50 Kw for about 6 hours which would be 300 Kwhr, now if the 'flow battery is $500 for one kilowatt hour, and sulphur is several times that, say 3X just to pick a #, then it would be on the order of 1500 bucks per Kwhr, then the 300 Kwhr unit would cost about a half million bucks per, so the 20 units they mentioned might be 10 megabucks.
    I wonder what regular lead/acid batteries would cost on a Kwhr basis. I think the regular Kmart/Sears battery at say, 80 bucks, stores about 1 Kw but only for say 15 min, just a guess here, but that would be about 0.25 Kwhr for 80 bucks and therefore 250 odd bucks per Kwhr. Of course the power storage dudes would probably want marine deep discharge batteries which would probably double the price so 500 bucks/Kwhr, not far off the 'flow battery' technology, whatever that is but still cheaper than sulphur. Now Sulphur would no doubt have lead acid beat on weight, probably 1/3 the weight and would not have to worry about lead disposal so each one has its pluses and minuses. One problem with lead acid batteries I see with larger installs is dealing with acid fumes that seep out of the cells in spite of better seals of the last few years. I saw the damage that does to electronics in the vacinity so that is a definite downside. The Lithium Ion battery has a lot more energy density than lead/acid but costs what, 3 times lead/acid? They come with their own brand of problems too, like exploding and such. I don't think there is any kind of storage technology that is totally risk free. Maybe underground compressed air, that seems logical too, pump air into an existing totally underground cave and line it with plastic or foam or something similar then just pump air at a 1000 PSI or thereabouts and if you have a cave a few hundred meters across, say 200 meters cubed, which can be parsed out in a long skinny cave or a cube, it wouldn't matter, then you have with those spec's, 80 million cubic meters of air storage. If that was compressed at 1000 PSI, sounds like a lot of KWhrs of storage to me, don't know the math for that, you have any idea of the KWhr V pressure V volume formula?
    That kind of a system would certainly not be transportable, being stuck to an existing cave but I bet it would be cheap.
  11. Subscribersonhouse
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    12 Oct '08 19:59
    I was rethinking the lead acid battery vis a vis the kwhr storage. They are rated in terms of amps for a certain amount of time, 10 minutes? To be able to crank out say, 900 amps, for 10 minutes, so lets go with that.
    Now 900 amps times 13 volts is close to 12,000 watts for 10 minutes and divide that by six gives you kwhr, which is 2 Kwhr, some 8 times what I said in the last post so the cost would be a lot less. Still have problems with acid vapor, oliums I assume.
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