California's Grid May Soon Store Energy In Giant Ice Packs 

California's Grid May Soon Store Energy in Giant Ice Packs

California wants better batteries, which is why the electric company Southern California Edison is planning a set of, let's say, unconventional energy storage solutions, including huge 450-gallon ice packs. Why? It all has to do with a little-known problem with California's wind-reliant electric grid.

Wind turbines, you see, spin merrily into the night, generating surplus power even when there aren't enough people awake to use it. That's why electricity is often cheaper at night. Sometimes, the situation gets so absurd that the price of electricity actually drops below zero and becomes negative. The most obvious solution is to store that energy until demand is up again, but building batteries with hundreds of megawatts of capacity — enough to power millions of lightbulbs — is a tall task.

Recently, the New York Times reports, Southern California Edison held a competition to figure how to keep up after retiring a nuclear generator and natural gas units. Instead of constructing many new power plans, the electric company decided to build better batteries, including what will be the largest lithium battery in the world.

California's Grid May Soon Store Energy in Giant Ice Packs

Credit: Ice Energy

Even more intriguing, though, is the Ice Bear system, which uses ice for air conditioning. (AC is, of course, a huge strain on the electric grid in the hot California summer.) The Ice Bear system freezes water inside 450-gallon rooftop tanks using excess energy during the night. As the ice melts during the day, it's used to cool air that is pumped down inside for air conditioning.

The Ice Bear system has been used at a relatively small scale for a few years, but this will be its real test for scaling up. The contract with Southern California Edison is bigger than all of its others combined. If electric grids are ever going to become more reliant on wind and solar farms — which can't just shove more fossil fuel into the furnace (like coal or power plants) when electricity demand is up in the afternoon — we'll need bigger and better batteries. Maybe even those made of ice. [New York Times]

Top image: Wind turbines in California. AP Photo/Rich Pedroncelli

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    Am I missing something here. They want to make a huge battery but then they talk about using ice for air-conditioning. Then to cap it off, the story says they need bigger and better batteries, maybe even ones made out of ice. Sorry, I don't see the correlation.

      Yep you're missing a 'connection'... Grade school science gives the answer

      A battery is a store of a Potential Chemical Energy, using Nickel, sodium, lithium etc

      This article is about di-hydroxide batteries, or H2O, as it defrosts (as a battery discharges energy) it releases the energy into the building in the form of heat exchange.. I'd be willing to guess though there is some form of metal, or sodium, used as a catalyst to enable melting to occur evenly.

        The way I read it, it's simple make ice at night to cool the building in the day. The same as heating water at night on cheaper electricity rates. It not battery per say, it thermal storage.

          lol thermal storage is still just another name for a battery type though CPE's wiki covers thermal storage

          It's a fairly ambiguous definition though, for instance a chilly bin could fit them term

      The storage of energy is in the form of ice, though not so much like a battery but rather you off set the use of electricity in the form of air conditioners during the day. That way the energy generated at night does not get wasted.

      An interesting idea, though I wonder what they'd do in the winter. Does the system have scope to store energy in the form of heated water and use that for heating?

        I think cooling is more of an issue in California, but that would also be an interesting thing to look into. The main problem is that liquid doesn't hold it's heat very well so it'd probably end up all going very quickly in the morning, instead of being balanced out through the day. But then again, that's when people use a lot of electricity trying to get the temperature up to a base level. Maintaining it would use much less electricity.

    Why no just store the excess energy kinetically. They do this in places where they have hydro dams where they have too much power. The damn buys some power back from the grid at real cheap prices to pump water back up to the top of the dam.

    The US' new aircraft carrier will have a kinetic energy storage system consisting of big rotating disks, that can store 100MJ of energy. Why not have a bunch of these to store energy at night to be released during the day?

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