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posted by martyb on Friday January 23 2015, @06:15AM   Printer-friendly
from the bright-ideas dept.

The MIT Technology Review has an article on the problems faced by Hawaii in rolling out the large scale energy storage required to back solar power generation.

The prospect of cheaper, petroleum-free power has lured the Kauai Island Utility Cooperative (KIUC) to quintuple utility-scale solar capacity over the past year, building two 12-megawatt photovoltaic arrays. These facilities are the biggest and a significant contributor to the island’s 78-megawatt peak power supply. When the second plant comes online this summer, peak solar output on Kauai will approach 80 percent of power generation on some days, according to Brad Rockwell, the utility’s power supply manager.

That puts Kauai on the leading edge of solar power penetration, and KIUC has bruises to show for it. Power fluctuations from a first large plant installed in 2012 have already largely burned out the big batteries installed to keep solar from destabilizing the island’s grid.

The article looks at the problems experienced by the current power storage solution, and the proposals to deploy large scale Lithium Ion batteries in the next generation of solar plants.

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  • (Score: 2) by kaszz on Friday January 23 2015, @07:26AM

    by kaszz (4211) on Friday January 23 2015, @07:26AM (#137165) Journal

    Use Sodium-Sulfur battery [wikipedia.org] or make use of molten salt [wikipedia.org] for non-shine hours ..?

    I don't think Lithium batteries are suitable for this purpose.

    • (Score: 1, Informative) by Anonymous Coward on Friday January 23 2015, @12:22PM

      by Anonymous Coward on Friday January 23 2015, @12:22PM (#137215)

      > I don't think Lithium batteries are suitable for this purpose.

      Lithium is good as long as you stay away from the margins. If the battery bank is large enough that they can stay within the 25%-75% range they will get a lot of cycles out of it.

    • (Score: 2) by nitehawk214 on Friday January 23 2015, @03:27PM

      by nitehawk214 (1304) on Friday January 23 2015, @03:27PM (#137263)

      This is a photovoltaic system. They don't have a heat transfer loop.

      --
      "Don't you ever miss the days when you used to be nostalgic?" -Loiosh
  • (Score: 2, Interesting) by bradley13 on Friday January 23 2015, @08:14AM

    by bradley13 (3053) on Friday January 23 2015, @08:14AM (#137175) Homepage Journal

    This makes so little sense - just like so many other green boondoggles actually designed to line someone's pockets - that I smell a federal subsidy. A little research, and voila: here it is [energystorageexchange.org], or at least one part of it.

    --
    Everyone is somebody else's weirdo.
    • (Score: 1, Insightful) by Anonymous Coward on Friday January 23 2015, @12:27PM

      by Anonymous Coward on Friday January 23 2015, @12:27PM (#137217)

      > I smell a federal subsidy.

      Name one large-scale energy installation that does not have federal money behind it in one way or another.
      Hell, the panels on my roof got me a 30% federal tax credit, so even the small-scale installations have subsidies.
      Beware of drawing meaning from the ordinary, that's what conspiracy theorists do.

      • (Score: 4, Informative) by Thexalon on Friday January 23 2015, @04:02PM

        by Thexalon (636) on Friday January 23 2015, @04:02PM (#137277)

        Name one large-scale energy installation that does not have federal money behind it in one way or another.

        To expand on that very accurate point: Pretty much every major industry in the US has government support of some sort or another. To stick solely to the energy sector:
        - Oil: Ridiculously cheap access to public land and US waters. And easy access to eminent domain to force property owners to allow them to do, well, pretty much whatever they want. And overseas wars to secure foreign sources of oil at discount prices.
        - Coal: Like oil, ridiculously cheap access to public land. If they had to buy an easement from private owners to remove a mountaintop, coal would be much more expensive than it is. And somehow not having to pay out enormous amounts to treat black lung disease, which almost everybody who works in coal mines gets sooner or later.
        - Nuclear: The government is involved with just about every stage in the process, in part because they want to keep very close track of what happens to nuclear fuel.
        - Hydroelectric: Most of the largest dams are government projects.

        When pushing a new technological development, this kind of government support isn't necessarily a bad thing: It's how we ended up with the Internet, for example. The problem is that once the new technology is ubiquitous, the companies that were on the receiving end of the government support can now afford an army of well-heeled lobbyists to prevent the supports from going away when they are no longer useful.

        --
        The only thing that stops a bad guy with a compiler is a good guy with a compiler.
    • (Score: 3, Informative) by DeathMonkey on Friday January 23 2015, @07:19PM

      by DeathMonkey (1380) on Friday January 23 2015, @07:19PM (#137387) Journal

      This makes so little sense - just like so many other green boondoggles...
       
      The Kōloa array generates electricity at a cost of about 11 cents per kilowatt hour compared to about 23 cents for electricity created by burning oil. This will help KIUC meet its goal of reducing the average residential bill by at least 10 percent over the next 10 years.
        reference [kiuc.coop]
       
      Some boondoggle...
       
        ...actually designed to line someone's pockets ...
       
      These are that pockets that will be lined:
      Kauai Island Utility Cooperative (KIUC) is a not-for-profit generation, transmission and distribution cooperative owned and controlled by the members it serves.
        reference [kiuc.coop]

  • (Score: 1) by anubi on Friday January 23 2015, @08:41AM

    by anubi (2828) on Friday January 23 2015, @08:41AM (#137180) Journal

    I propose to store any excess electrical energy by changing the phase of water from liquid to ice.

    Do this during the day when power is available. Size refrigeration compressors to be able to make ice at whatever rate the excess power will allow.

    Then use this ice first thing for all cooling needs, whether it is for air conditioning or industrial refrigeration.

    ( Chilled water loops and small circulating pumps ).

    There are quite a few ways for storing energy. Batteries are just one of them.

    Being a lot of that energy is going to be used for thermal management, then store that energy in an ice bank, as its really hard to wear water out by repeatedly freezing and thawing it, but a helluva lot of energy can be stored by doing this.

    Batteries are an awful expensive way to store energy destined for thermal management anyway, might as well convert to thermal while you have the excess energy then store as a thermal phase change.

    Save the electricity for things like lighting, fans, or circulating pumps. The elephant in the room - the compressor - has already been fed by the panels in the heat of the day.

    I have been experimenting with this technology and it sure looks promising.

    In an industrial environment, I find propane gas ( the very same stuff you burn in your barbeque ) is also an excellent refrigerant, matter of fact its well known for its thermodynamics and has already been assigned a refrigerant number: R-290.

    Danfoss has done a lot of research on using R290 and has a quite informative .PDF of it here... [europa.eu]

    Propane has some really nice thermodynamic and chemical properties - yet most people burn the stuff as a fuel.

    Think they would need any help implementing such a thing?

    --
    "Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
    • (Score: 2) by nitehawk214 on Friday January 23 2015, @03:48PM

      by nitehawk214 (1304) on Friday January 23 2015, @03:48PM (#137271)

      Interesting, but I was always under the impression that refrigeration was inefficient. Wouldn't it be best to try to store the energy in the most efficient way possible?

      --
      "Don't you ever miss the days when you used to be nostalgic?" -Loiosh
  • (Score: 0) by Anonymous Coward on Friday January 23 2015, @02:20PM

    by Anonymous Coward on Friday January 23 2015, @02:20PM (#137241)

    One can store about 100kW of energy in a water heater tank. People should invest in well insulated electric water heater tanks and heat water mostly when there's excess of solar production (control signal provided by the utility company via internet, fm radio, etc.).

    • (Score: 0) by Anonymous Coward on Friday January 23 2015, @11:04PM

      by Anonymous Coward on Friday January 23 2015, @11:04PM (#137463)

      Really, only 100 kW ? I can store 1000000 kW in mine. But only for a few microseconds...

      Power and Energy. Learn the difference.

    • (Score: 2) by HiThere on Saturday January 24 2015, @12:42AM

      by HiThere (866) Subscriber Badge on Saturday January 24 2015, @12:42AM (#137490) Journal

      I think they'd do better using compressed air storage. As this is an island, they've got plenty of water to apply pressure. All you need is a big piston chamber (or a lot of small ones). Force the air down, which compresses it. To extract the power use the air pressure to spin a turbine. (To make this a bit more efficient you can also burn a bit of gas to heat the air as it enters the turbine, but this isn't necessary if that's too expensive.)

      --
      Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
  • (Score: 0) by Anonymous Coward on Friday January 23 2015, @03:07PM

    by Anonymous Coward on Friday January 23 2015, @03:07PM (#137256)

    nothing beats a ton of spinning copper wire for frequency regulation.
    from article it is not known if the batteries feed directly into the AC grid or how.
    the ton of spinning copper should be driven by the batteries instead.

    in a thermic powerplant a shaft connects the mechanical "turbine" to the ton of spinning copper -aka- generator.
    obviously ten thousand solar inverter are "a good thing" but they only work if their is a "heart-beat" on the grid and like mentioned above, nothing provides a better "heart-beat" then spinning copper ...

    as for what constitutes a "battery", it could also be toxic liquid graviton infused di-hydrogen-oxid or even just solo-hydrogen as a gas all by itself.
    with hydrogen then fuel-cells spring to mind but these are direct current and need electronics to convert to AC, thus not qualifying as a stable "heartbeat" source.

    i think 80% peak isn't enough but rather expand to 400% peak and solar-inverters that can limit output and then letting some pump lift some water (ocean water?) to +100 meters and also making hydrogen.

    chemical lead-ion-whatever-batteries and a AC grid are a lost cause, unless driving a DC motor which via mechanical shaft drives "a ton of copper".

    +100m gravitational di-hydrogen-oxid and solo hydrogen can be converter "directly" into copper-heartbeat-AC without need of converting from DC.

  • (Score: 0) by Anonymous Coward on Friday January 23 2015, @06:24PM

    by Anonymous Coward on Friday January 23 2015, @06:24PM (#137359)

    If there's one thing that I think of with Hawaii, its the potential for geothermal energy. No need for storage and plenty of capacity... well, on some islands I suppose. Are all the islands "hot"?

    • (Score: 3, Informative) by urza9814 on Friday January 23 2015, @08:07PM

      by urza9814 (3954) on Friday January 23 2015, @08:07PM (#137399) Journal

      If there's one thing that I think of with Hawaii, its the potential for geothermal energy. No need for storage and plenty of capacity... well, on some islands I suppose. Are all the islands "hot"?

      IIRC, only one of the islands is really "hot" -- the way the chain forms is the tectonic plate moves across a single hotspot, so a mountain builds above that spot until it moves out of the way, then it erodes back into the sea. So the big island is certainly hot, but the rest may not be.

  • (Score: 0) by Anonymous Coward on Saturday January 24 2015, @07:59AM

    by Anonymous Coward on Saturday January 24 2015, @07:59AM (#137571)

    At some point, the grid needs to be DC. This removes all synchronization and phase issues, which enables simple distributed generation and removes a huge vulnerability in the current AC grid. Because of the synchronization issues and how it is managed, networked controllers have the ability to reverse the polarity and destroy equipment.

    Why was the power grid not built with DC to begin with? Because raising the DC voltage for distribution and lowering it for consumption was terrible with the technology of the time. Often, instead of raising and lowering the voltage, the amount of copper was increased, making it more expensive. Transformers were cheaper and better, but they only work with AC. Wall warts lowered the voltage too using the same technology, except they lower the voltage a step further.

    Notice your wall warts getting lighter? To improve efficiency and cut costs, we replaced the transformer with solid state electronics. Data centers are now switching to DC mains to remove an unnecessary conversion step between the battery and mains voltage. Because computer power supplies do not assume that the mains is AC, you can feed them DC just as easily. Most solid state wall warts can also consume mains DC without any modification.

    To improve the efficiently in larger motors, solid state circuits are used to convert the mains AC into DC and then into 3 phase AC. If they started with DC to begin with (by removing that AC to DC step), they would be more efficient if the power source is DC.

    Heating elements, of course, do not care if the current is AC or DC.

    It seems that all major appliances are going to become DC compatible as a means of increasing efficiently. The transformer is going away and we are getting better at raising and lowering DC voltage using solid state electronics with higher voltages.

    Now that data centers are built with DC mains, we need to scale that technology up for utility DC distribution, and up again for utility DC transmission. If we adopt more PV solar and use smaller and distributed natural gas generators, we eliminate the need for expensive, unnecessary, and vulnerable extra high voltage lines. This also makes it far simpler for each building to contribute power back into the grid, either from a PV solar array during the day, or selling back power from excess electric car battery capacity during the night.

  • (Score: 1) by anti-NAT on Tuesday January 27 2015, @02:10AM

    by anti-NAT (4232) on Tuesday January 27 2015, @02:10AM (#138394)

    but it seems the world is full of fools.