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  • I agree with most of what jflorey2 says about nuclear power, but worry about reliability and cost. The next few reactors built may go a long way towards reassuring doubters on those scores.

    As for "small amounts of storage" helping peaker plants be more efficient, I meant "20 minutes of storage", which is how much longer it takes to start up a combined cycle peaker vs. a simple cycle one. That's small relative to the 8 or 24 hours of storage needed for other applications.
    17kw. I like science, but I'm no expert.

    Comment


    • Originally posted by DanKegel View Post
      Let's look at our points of agreement, and see if we can expand them. Starting with load shifting:



      Aluminum smelting seems like a great example. After looking a bit at the literature, I see various discussions about the desired level of heat loss from the sides, bottom, and top of aluminum electrolysis cells. There has been a lot of trial and error over the years learning how to optimize the cells. It's not unlikely that, given proper incentives, industry could gradually reduce heat loss significantly. That would take many years, but since industry is always trying to reduce operating costs, it's kind of already underway.
      We have a couple decades to ramp down our co2 emissions to zero, which is enough time for industry to adjust -- assuming we set clear targets and incentives.

      But there are nimbler sectors. For instance, demand-management-capable heating and cooling equipment is already practical and being deployed in small numbers. http://ladwp.com/powerirp shows LADWP's 2015 plan included 200 to 500 MW of demand management by 2026. I'd bet you a beer that number will increase in their 2016 plan.

      How much do you think load shifting can help in the next ten years?
      Dan: It looks to ne like you know little to nothing about aluminum smelting. Process heat loss has been reduced about as far as is practical, reasonable, cost effective given available and likely future technology and methods. The pots operate at ~ 900-1,000 C. The pot liners/insulation reduce heat loss and external surfaces temps. to levels safe for personnel. More reduction is of a minor advantage and not worth it. Simple physics- in this case heat transfer. Probably 90 % of the heat loss has already been eliminated - if not by economics then practicality. If that's not enough, rest assured OSHA has effectively mandated temps. for safety reasons. To snag, say, 90 % of the existing and remaining heat loss would be quite impractical from a handling and process standpoint, not necessary and not cost effective using any reasonable and possible insulating materials. Additionally, the insulation is already quite robust for another and unrelated reason: cheap insurance. If power fails and pot contents cool and harden, it's very costly. Adequate or even over-robust insulation provides a bit more time after power outage before things solidify, with time of the essense in such situations.

      Aluminum production is, by its very nature, more energy intense than, say, steel production (except for steel made with electric furnaces - mostly using scrap for low grade steel like car bodies, etc.) mostly because AL production uses electricity as a heat source rather than direct use of fossil fuel. Electricity, because of its low entropy, requires about 2-3 Watts of heat equivalent fossil fuel energy (say 8 or 9 BTU), to produce about one Watt of electrical energy (about 3.4 BTU). That's where most of the energy cost originates. That, and other metallurgical reasons, means it takes about 4 or more times as much energy to produce AL, as steel. That's the way the process works and why aluminum plants were and still are located close to hydro plants - about the cheapest source of electricity production available. If aluminum could be made using fossil fuel as the direct energy source instead of first turning the fossil fuel energy into electrical energy, the energy budget to make AL would be less. The process heat loss is really peanuts in spite of what you may think you know.

      As for CO2 production and AL smelting - that's not the biggest problem, although polyaromatic hydrocarbons (C and H only) of some concern as the anodes are consumed - but that's not CO2. Perfluorocarbons and hydrogen fluoride as gases, and sodium and aluminum fluorides are of major concern.

      To me, and IMO only, another example where you're a loose cannon and spout off because you may have read some crackbrain's wet dream. I'd suggest you do your homework and get it right. You're out of your knowledge depth.

      Comment


      • Originally posted by J.P.M. View Post
        Process heat loss has been reduced about as far as is practical, reasonable, cost effective given available and likely future technology and methods.
        From what I read, heat loss from the bottom of the cell is pretty low, but there's significant loss from the sides and the top; reducing those is possible, but the heat leakage has some benefits for the operation of the cell, so a lot of innovation would be required to keep the cell producing properly without that heat loss. Innovation requires lots of expensive R&D (and trial and error), so it won't happen unless there's a financial incentive. One possible big incentive is that an aluminum smelter that could quickly manage its energy demand could bid on demand markets and get paid quite a bit for ramping down during peak fossil fuel demand hours. And lower heat loss would make it easier to do that.

        About co2 production - http://climate.columbia.edu/files/20...-Factsheet.pdf shows that about half of the co2 in aluminum production is indirect, from the energy used to run electrolysis (though that depends on where the electricity comes from, of course). That's the co2 emissions I'm mostly thinking of. If the smelter is run on solar and wind 90% of the time, it'll cause much lower emissions.
        17kw. I like science, but I'm no expert.

        Comment


        • Originally posted by DanKegel View Post

          From what I read, heat loss from the bottom of the cell is pretty low, but there's significant loss from the sides and the top; reducing those is possible, but the heat leakage has some benefits for the operation of the cell, so a lot of innovation would be required to keep the cell producing properly without that heat loss. Innovation requires lots of expensive R&D (and trial and error), so it won't happen unless there's a financial incentive. One possible big incentive is that an aluminum smelter that could quickly manage its energy demand could bid on demand markets and get paid quite a bit for ramping down during peak fossil fuel demand hours. And lower heat loss would make it easier to do that.

          About co2 production - http://climate.columbia.edu/files/20...-Factsheet.pdf shows that about half of the co2 in aluminum production is indirect, from the energy used to run electrolysis (though that depends on where the electricity comes from, of course). That's the co2 emissions I'm mostly thinking of. If the smelter is run on solar and wind 90% of the time, it'll cause much lower emissions.
          Dan, you keep making uninformed statements in areas where you are ignorant.

          The smelting of AL is a continuous process. As such, ramping electricity demand is effectively impossible or at least very impractical. Scheduling continuous output in blocks of hundreds or thousands of hrs. may be possible for a smelter. However, market demands, as a way of getting a lower price for slack periods won't work well because market demand, as can be seen from T.O.U. rates, as an example, are a bit more volatile time wise. Dedicated, company owned generating facilities as are sometimes used would make that argument moot anyway.

          There are no benefits to selective heat loss and few are possible anyway. The heat loss through the anode and cathode is mostly independent of temp. and thus pretty constant in a practical sense. Because high temp. insulation is mostly a matter of finding materials with low and stable thermal conductivity at relatively high temps. (unlike low temp. insulating materials which mostly rely on using air's low thermal conductivity and prevent its movement via natural convection), things have not changed a whole lot over the years. Hope springs eternal and research continues, but I wouldn't hold my breath waiting for someone finding something more practical and cheaper than current kiln lining/firebrick materials.

          There are some advantages and efficiency gains to be realized by increasing the current and lowering the voltage applied to the cell, which seems to be a better way to save energy, provided the increased current load can be considered during design and managed. The simplified story, as it turns out, is that the pot energy (heat) loss is, among other things, f(pot applied voltage - voltage required to produce AL). In effect, the bigger the difference between the two voltages, the less efficient is the process. That inefficiency is expressed as waste heat- that is, higher temperatures. So, like many other things dealing with energy, not needing the energy in the first place- in this case by reducing the excess applied voltage - is always better, more efficient and cheaper.
          Last edited by J.P.M.; 12-06-2016, 06:35 PM. Reason: Spelling.

          Comment


          • JPM you are a smart man, so are the moderators with their hands tied up. You can connect the dots. This thread was started about a year ago by Vertiass or something like that. It had one purpose, to start a chit storm with make believe science the kind Dan endorses. In fact it got the OP banned. Now Dan has picked up the slack and keeping it going. In fact every thread Dan starts is intended to start trouble using the same VooDoo Science.

            Dan is easy to find in the net. He has been banned from many forums. Makes one wonder.
            MSEE, PE

            Comment


            • Originally posted by Sunking View Post
              JPM you are a smart man, so are the moderators with their hands tied up. You can connect the dots. This thread was started about a year ago by Vertiass or something like that. It had one purpose, to start a chit storm with make believe science the kind Dan endorses. In fact it got the OP banned. Now Dan has picked up the slack and keeping it going. In fact every thread Dan starts is intended to start trouble using the same VooDoo Science.

              Dan is easy to find in the net. He has been banned from many forums. Makes one wonder.
              I believe I understand what's going on. It's mostly, and down at the bottom line, about revenue.

              Since I seem to recall Dan K. had something to do with it, I suppose I'll wind up the same way Russ did, but I'll keep calling B.S. when I see/smell it, from Dan or elsewhere and take my chances. Otherwise, sooner or later, if I roll over to what I consider Dan's type of loose cannon damage, keep my pie hole shut and go along to get along, sooner rather than later, I wind up a moral idiot.

              I don't usually wear it on my sleeve, but R.E. is important to me, solar in particular. A fast analogy that may serve to describe how I feel: The actions of Dan and his ilk give me a lot of the same feelings I might have toward a strip joint owner that employed my beautiful but vulnerable and naïve daughter as a stripper or private dancer, and even kept the tips.

              I'll stay civil, call balls and strikes and take my chances.

              What the owners/admin. think about my mental spoor, even being as civil as I usually try to be while still being honest and hopefully technically accurate, is out of my control. I'm sensitive to and certainly understand their predicament - if it can be called that. However, and whatever its called, I see it as theirs, and, while I don't see it as a predicament, I see a clear path forward. Any shackles, if they exist at all, are of their own doing and in their own mind. In the end, their forum, their table/game/rules.

              Add: FWIW on smarts, I believe most folks are about equally smart, or dumb I guess. I'm just lucky.
              Last edited by J.P.M.; 12-06-2016, 06:46 PM. Reason: Added add.

              Comment


              • Originally posted by Sunking View Post
                Dan is easy to find in the net. He has been banned from many forums. Makes one wonder.
                ? Which ones? I don't recall being banned.

                I have to say, the continual baseless attacks on my character by Sunking and J.P.M. are amazing in their virulence.

                That the mods allow those attacks to continue gives me pause. I guess the mods, collectively, must agree with Sunking and J.P.M. If that's not the case, please let me know.
                Last edited by DanKegel; 12-06-2016, 07:09 PM.
                17kw. I like science, but I'm no expert.

                Comment


                • Hello, where to start

                  The majority of people who come to this forum dont know squat about solar or energy production, so should we ban everyone??
                  J.P.M dont speak on behalf of the forum owners "I believe I know whats going on" ...tripe, and If you dont like it dont let the door hit you on the ass on the way out.
                  SK, that goes for you too, what proof have you that dan is here to make trouble, he may be naive and silly but he is never rude. Its OK to be wrong about things, its called debating an issue.
                  Dan, stop posting every bit of pie in the sky crap that you come across, perhaps a bit of research first.

                  I am doing what perhaps I should have done long ago and closing this thread.

                  P.S of the complaints I get from users on this site all three of you are the main culprits.
                  S.K..."is rude"
                  J.P.M ...."is condescending"
                  Dan..."is full of crap"

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