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  • #31
    We have had remote shutdown of heating loads etc for the last 70 years or so but in no way is it third world power, it is however cheaper power. We have our domestic hot water on remote control but we could have other loads too. Irrigation pumps, stored hot mass home heating, pool heating etc.

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    • #32
      An interesting talk from electrical engineers on renewable energy. Especially solar and wind.



      Andrew Dodson - Issues Integrating Renewables @ TEAC6


      Its on youtube.

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      • #33
        Aren't we cynical????
        the plant I'm talking about were both privately owned, not tied for grid peak support per-se, but solely for profit... pumping a lake out of a 1000 foot hole burning 'free' off peak power, and getting a little bit back when sellable- just seemed a terribly inefficient way to store a little (even if normally wasted) power...surely theres got to be a better way...

        in europe many homes have a 'trombe wall' thermal passive solar heating- using simple mass damping works very well, no moving parts or conversion losses at all... I still think a flywheel or capacitor could be a far more efficient alternative to the heavy losses associated with pumping air or water- but what do i know-I'm just a tinkerer...
        Last edited by tc429; 05-04-2015, 10:09 PM.

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        • #34
          Pumping water can be much more efficient than air, which incurs throttling losses all over the place. I don't have figures for the efficiency at Taum Sauk, but if it didn't make good sense, the powerco would not have rebuilt the place, or built it to begin with..

          Originally posted by The Artful Bodger View Post
          We have had remote shutdown of heating loads etc for the last 70 years or so but in no way is it third world power, it is however cheaper power. We have our domestic hot water on remote control but we could have other loads too. Irrigation pumps, stored hot mass home heating, pool heating etc.
          If it sticks with those, OK. What I've been seeing is a LOT of things covertly or overtly equipped with the remote control.

          As for third world power, IIRC there were rolling blackouts in LA or some such place in the relatively recent past....

          our entire house has passive temperature stabilization, it's a brick house, with plaster walls inside. many many tons of "stone", and takes typically 3 days to heat up or cool off to ambient temps unless actively heated. (we don't use A/C)
          Last edited by J Tiers; 05-04-2015, 11:41 PM.
          CNC machines only go through the motions.

          Ideas expressed may be mine, or from anyone else in the universe.
          Not responsible for clerical errors. Or those made by lay people either.
          Number formats and units may be chosen at random depending on what day it is.
          I reserve the right to use a number system with any integer base without prior notice.
          Generalizations are understood to be "often" true, but not true in every case.

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          • #35
            Are you sure those are remote control not monitoring devices?

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            • #36
              Originally posted by The Artful Bodger View Post
              Are you sure those are remote control not monitoring devices?
              Got your tinfoil hat on today so "they" don't stop you from mentioning that?

              http://zapatopi.net/afdb/

              I assume they are shutoffs, they are described as being "smart grid enabled". The water heaters are explicitly "smart grid enabled" and have shutoffs, so I would expect that other devices using the same descriptive language are the same.

              It seems pretty invasive, especially for very small loads. For large industrial users I can see it, but it would take a huge number of water heaters to make much difference.

              It takes 500 2 kw loads to make up 1 megawatt, which is about half the power of a regular rail locomotive. Possibly 250 water heaters, depending.

              By contrast, one wind farm can be 50 to 100 mW. A short term drop to half power in one such would require shedding a load of many thousands of water heaters, especially since not all would be "on" at the time.

              Seems like a lot of work. Also seems like aiming at consumers instead of the real target.... Similar to focusing on cars and ignoring huge power plants and large industries as far as carbon emission and pollution. (Oh, wait, who has all the money?)
              CNC machines only go through the motions.

              Ideas expressed may be mine, or from anyone else in the universe.
              Not responsible for clerical errors. Or those made by lay people either.
              Number formats and units may be chosen at random depending on what day it is.
              I reserve the right to use a number system with any integer base without prior notice.
              Generalizations are understood to be "often" true, but not true in every case.

              Comment


              • #37
                As Artful has pointed out, NZ has had load management in place for a vey long time primarily via domestic water heaters. Yes.,., it take a lot of 4-5KW water heaters to make much difference, but... due to the lack of piped gas, NZ primarily heated domestic water via electricity; maybe a million heaters? When I was there it was called "ripple control" - 500hz or so (?) control signal was superimposed on the mains to turn the loads on and off by substation or local region. Works very well.

                And not just NZ : it's in several much larger population counties : http://en.wikipedia.org/wiki/Load_management. The UK example cited states 5GW is night "storage" heaters.
                Last edited by lakeside53; 05-05-2015, 12:36 PM.

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                • #38
                  This has been a good discussion I will add a little insight to some of this. In North America we have several Agencies that have oversight of the electrical Grid. WECC in the West that is where I work ERCOT in Texas and a half dozen in the East. Each company is connected to the Grid and they are responsible for Frequency and voltage and a specified amount of spinning reserve. Spinning reserve is basically more energy than what you are using to cover sudden outages. Each balancing area has schedule of power to supply or use this is a dynamic system the interconnections helps everyone connected to absorb changes to the system.

                  Wind generation has to be held to less than roughly 20% of total generation on line at any given time due to wind being somewhat unpredictable. The problem is the fastest generation sources usually take at a minimum of 20 minutes to bring up most plants much more time.

                  During off peak times usually the middle of the night there is excess power available these pumping plants help keep voltage from going too high. There are many different devices on the system that either boost or reduce voltage. Long high voltage lines that are lightly loaded act like a capacitor and raise voltage. They don’t like taking these lines out of service because of making the system less able to take some other outage like a loss of another line or generation source or path.

                  Nuclear plants are probably the slowest to make generation output changes having a pumping plant in the system to use this excess power during non-peak times makes sense pump water during off peak to help regulate this excess energy and then generate power with the stored water during peak energy times.

                  Solar is a more predictable energy source than wind. A few years ago Texas came really close to black out due to having too much of their generation from wind and the wind suddenly stopped blowing sending them into a load shed situation.

                  A smart grid makes sense being able to switch off non-essential loads in case of a disturbance in the grid to stop cascading outages.

                  I am a NERC certified transmission operator for my company and operate a portion of the system. I posted this information from memory I am not an expert in explaining how everything works but I have a pretty good grasp on the big picture and how each device and line works in relation to the system.

                  We are continually trained and tested to operate in order to keep our operator license up to date.

                  I can see where people might think pumping water to use later to generate looks inefficient and you are right but because there is excess energy during off peak times that can't just be shut down easily and brought back up it makes sense. We use Shunt reactors as well as other devices to lower voltage they act like a big toaster and that energy is just being used for no use so pumping water rather than using one of these reactive devices makes more sense when you look at it that way. Charging a battery or any other use of this excess power just makes sense to me.

                  The reactive devices capacitors to raise reactors to lower are also used to make power flow in the direction we want it to go as well a phase shifting transformers. The system is very dynamic and is always changing.

                  Mike
                  Last edited by gundog; 05-05-2015, 12:41 PM.

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                  • #39
                    Originally posted by gundog View Post
                    Long high voltage lines that are lightly loaded act like a capacitor and raise voltage. They don’t like taking these lines out of service because of making the system less able to take some other outage like a loss of another line or generation source or path.
                    Mike
                    Mike, what is the voltage in kV of the highest voltage transmission line in use in the US today? Any plans that you know of for even higher voltage lines? I'm sure there has to be a point of diminishing returns, where the physical size of the tower and the cost of exotic material in the insulator string exceed any benefit.

                    Is the true failing of the grid in the US, the interconnects and the inability to send the power efficiently with minimal loss from where it's generated to where it's needed in peek load situations?

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                    • #40
                      Originally posted by gundog View Post
                      Nuclear plants are probably the slowest to make generation output changes having a pumping plant in the system to use this excess power during non-peak times makes sense pump water during off peak to help regulate this excess energy and then generate power with the stored water during peak energy times.
                      If I'm reading the wiki citation above correctly, that's what the UK does - uses domestic night storage heaters to provide 5GW load for the nuclear excess.

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                      • #41
                        Originally posted by Rosco-P View Post
                        Mike, what is the voltage in kV of the highest voltage transmission line in use in the US today? Any plans that you know of for even higher voltage lines? I'm sure there has to be a point of diminishing returns, where the physical size of the tower and the cost of exotic material in the insulator string exceed any benefit.

                        Is the true failing of the grid in the US, the interconnects and the inability to send the power efficiently with minimal loss from where it's generated to where it's needed in peek load situations?
                        The largest I know of is an East West 750Kv DC line. The largest my company has is 500 Kv AC lines. I worked 20 years as a lineman before a back injury forced me into this gig and I was one of a few who performed 500 Kv barehand work. Do a google search on barehand transmission work you may find it interesting.

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                        • #42
                          Originally posted by gundog View Post
                          The largest I know of is an East West 750Kv DC line. The largest my company has is 500 Kv AC lines. I worked 20 years as a lineman before a back injury forced me into this gig and I was one of a few who performed 500 Kv barehand work. Do a google search on barehand transmission work you may find it interesting.
                          The first electric utility I worked for Pacific Gas and Electric in California has a system like this do a google search for the Helms Project it is a very intersting read PG&E won some engineering awards for that.

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                          • #43
                            Here is a link to a storage system using electric locomotives on an 8 mile incline. They can cycle several load trains to the top and store them on sidings until the need for electricity arises. They claim they can spool up in 5 to 10 minutes.

                            http://www.aresnorthamerica.com/arti...to-store-power

                            Edit: here is a video clip I found interesting on the actual deployment of the loads.

                            https://vimeo.com/48344799
                            Last edited by Ironwoodsmith; 05-05-2015, 03:39 PM.

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                            • #44
                              I assume they are shutoffs, they are described as being "smart grid enabled".
                              They might be shutoffs and may be able to be use for grid levelling but are you sure these devices are not being added to new appliances as an enticement to the purchaser? For example, you put dinner in the oven before leaving for the day and turn it on from your smart phone when starting on the way home or maybe more importantly turn it off if you are delayed.

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                              • #45
                                That's the "internet of things".... a different animal. Maybe they have that too.

                                And maybe the "promised" smart grid enabled stuff will not be out quite as soon as expected.... maybe someone decided it might not be as smart as it seemed. Who knows what wheezes lurk in the hearts of men?
                                CNC machines only go through the motions.

                                Ideas expressed may be mine, or from anyone else in the universe.
                                Not responsible for clerical errors. Or those made by lay people either.
                                Number formats and units may be chosen at random depending on what day it is.
                                I reserve the right to use a number system with any integer base without prior notice.
                                Generalizations are understood to be "often" true, but not true in every case.

                                Comment

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