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View Diary: Green Light!  Flywheel Energy Storage (228 comments)

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  •  Pumped hydro lumped in with coal? (14+ / 0-)

    The pumped hydro plants I have seen don't have any carbon output at all, or even any mechanism to create any. They're the same principle as a flywheel, just moving a mass to store energy.

    What they do is use excess electricity when it's not needed (such as from a breezy night at a wind farm) to pump water uphill, and during the day, when demand exceeds generating capacity, let the water flow downhill through a turbine to generate power.

    It would be nice if flywheels got smaller and more efficient; pumped hydro is damned cool, but not small or inexpensive.

    •  flywheels seem a better approach (8+ / 0-)

      Gravity-based mechanical storage is tied pretty severely to the amount of mass you can bring to bear on the problem. You can get much greater energy density in the flywheels. I like this solution a LOT.

      Why call it the "liberal media"? Because they think liberals are cowardly morons, and the media fits that description.

      by Orbital Mind Control Lasers on Tue Aug 10, 2010 at 10:31:21 AM PDT

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      •  They are both impressive (15+ / 0-)

        The promise I see in flywheels is that they can be scaled up or down, and placed very close to the load.

        Hell, I run a data center, and have an entire room full of big, expensive, rather nasty batteries - purely to keep me alive for the couple of minutes it takes the generators to come online.

        Being able to replace them with a sealed box would be an epic win.

        Pumped hydro works well at the bigger end of the scale. Put one next to a body of water, and you've got a nice buffer for a day hotter than expected, or less windy, or less sunny, and it has zero carbon footprint, and benefits areas with low oxygen content in the water.

        I hope someone from Liebert or MGE or APC is taking note. There are six "battery rooms" within a minute's walk of my desk. I am sure I'm not the only manager absolutely ready to write a check to replace a couple tons of lead/acid batteries with a flywheel system.

      •  Mass at what cost? (6+ / 0-)

        Hydro and compressed air use some pretty inexpensive and existing space for storage.  With flywheels you have to create and store that mass.

        Enough of this reality crap. I voted for MAGIC!!!

        by BobTrips on Tue Aug 10, 2010 at 10:48:19 AM PDT

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        •  It's not a one-size-fits-all (5+ / 0-)
          Recommended by:
          Andrew C White, wader, aaraujo, BobTrips, JeffW

          but I can very seriously see the benefits of a flywheel-type system, not only for power storage, but for improving stability and efficiency. A box the size of a dishwasher could house a flywheel big enough to have an impressive energy reserve.

        •  choose your tradeoffs (4+ / 0-)

          There's no simple "best" answer and we'll probably see some combination of all these things. Flywheels have the advantage of high storage density for mechanical, and high efficiency. Disadvantage is they're gyroscopic so they can't be used for large-scale storage on mobile platforms (ie cars, and don't quote the Porsche at me lest I get pedantic about it). Hydro is inexpensive and capable of big numbers, but requires enormous land resources to do it. Compressed air is portable but inefficient. The list goes on.

          For stationary base load stabilization, flywheels are a pretty awesome solution, actually.

          Why call it the "liberal media"? Because they think liberals are cowardly morons, and the media fits that description.

          by Orbital Mind Control Lasers on Tue Aug 10, 2010 at 11:28:51 AM PDT

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          •   I see a big problem with them (0+ / 0-)
            1.  What is the initial carbon cost to manufacture one?  What are they made of and where does the material come from?  Is it mined?  Recycled?
            1. Why do they only last 20 years?  I don't understand why they would only last 20 years- where does the friction occur that degrades them so quickly?

            No matter- I am a big fan of pumped hydro storage. It has been used for years and except for the initial carbon costs to build them they are virtually zero-polluting and dependable energy storage systems.

            •  Sometimes the 20 years is ... (4+ / 0-)

              "At least 20 years".

              And then there's the material fatigue that can destroy over time.

              Wind turbine towers and foundations are talked about in terms of a 20 year lifespan.  Some will last much longer, but because of the type of soil they are in some will fail due to the constant stressing.

              Being conservative the industry uses the short end of the lifespan.  If the numbers work at the short end then everything else is gravy.

              Enough of this reality crap. I voted for MAGIC!!!

              by BobTrips on Tue Aug 10, 2010 at 12:04:00 PM PDT

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            •  20 years to major overhaul (2+ / 0-)
              Recommended by:
              Andrew C White, mataliandy

              A lot of the installation - foundations, buildings, etc will last much longer than 20 years and won't need to be replaced.

              But after 20 years at 50,000 RPM, which is NOT quick wear, the bearings will be worn and there may well be stress fractures in the flywheel structure.  These components would need to be replaced, but they're not a large percentage of the overall carbon footprint or system mass.

              And in any rate they'll pay for themselves in terms of C02.

            •  No real problem (2+ / 0-)
              Recommended by:
              Andrew C White, BobTrips

              Most are made of steel plus one or more other metals or alloys. Steel and many alloys can be melted down and reprocessed for reuse.

              It's a wheel, it has bearings. That's where the friction is.

              In addition, the high rate of speed at which they spin causes metal fatigue. Over time (say, about 20 years), after the huge centrifugal forces have been working on the metal for a long enough time, some the atoms in the metal will have flowed a sufficient number of nanometers from where they started to create stress fractures, making the flywheel brittle. At that point the flywheel needs to be replaced.

              Here's a cutaway drawing of one.

              It's pretty simple technology.

              Beware the everyday brutality of the averted gaze.

              by mataliandy on Tue Aug 10, 2010 at 03:37:36 PM PDT

              [ Parent ]

        •  Pumped hydro... (3+ / 0-)
          Recommended by:
          mataliandy, NYFM, aaraujo

          ...needs a difference in height for the resevoirs. Compressed air needs a place for the tanks, just like a place for the flywheels. Just sayin'...

          Float like a manhole cover, sting like a sash weight! Clean Coal Is A Clinker!

          by JeffW on Tue Aug 10, 2010 at 11:40:07 AM PDT

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          •  We've got the resevoirs, we've got the "tanks"... (4+ / 0-)

            We've got something like 80,000 existing dams in the US.  We use only 2,500 for power generation and only a handful for pump-up storage.

            A study of existing dams on federal land found roughly 15% of existing dams to be usable for power generation.  They had adequate flow and height and were close enough to existing transmission lines.

            Link...

            The study did not count the number of existing dams which could be used for power storage but did say that the number was higher than that for power generation.  Which is exactly what one would expect.  A dam with good head and distance to transmission might get ruled out for power generation because it did not have adequate water coming in the 'short end' to keep power going day in and day out.

            So, shall we say 20+% of 80,000 dams might serve as pump-up sites?   A very rough estimate of 16,000 existing dams just waiting to be put into use?

            --

            Compressive air (CAES) needs to go underground.  No reason to build tanks like are used at the Macintosh CAES facility in Alabama.

            Here's good article on utility sized storage which includes a map of all the caverns, salt domes, aquiers, etc. that could be used for CAES.  

            Link...

            BTW, PG&E (CA utility company) is in the process of building a new CAES facility and one is underway in Iowa.  Another CA utility is building a pump-up and others are planned for Utah.

            Enough of this reality crap. I voted for MAGIC!!!

            by BobTrips on Tue Aug 10, 2010 at 11:59:47 AM PDT

            [ Parent ]

          •  Also environmental concerns. (2+ / 0-)
            Recommended by:
            mataliandy, JeffW

            There's a limited amount you can change the reservoir volume without causing damage to the ecosystem of the reservoir.  Pumping large volumes of water can also disturb the water temperature equilibrium and cause silting problems.

            •  We've got a lot of dams... (1+ / 0-)
              Recommended by:
              NYFM

              Those used for power generation and irrigation change elevation quite a bit throughout the year.

              At least for those dams with which I'm familiar - TN/NC area back east and CA out west - the shorelines have no 'ecosystems'.  They might grow a bit of annual grass as they go down, but largely there's no soil.  Between high and low water is pretty much a dead zone.

              A constant level reservoir used for pump-up would be something like a fresh water stream that experienced multiple tidal fluctuations per day.

              Enough of this reality crap. I voted for MAGIC!!!

              by BobTrips on Tue Aug 10, 2010 at 05:26:29 PM PDT

              [ Parent ]

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