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posted by mrpg on Saturday May 06 2017, @10:33PM   Printer-friendly
from the cool-idea dept.

California utility augments 1,800 air conditioning units with “ice battery”

A Santa Barbara-based company called Ice Energy has partnered with NRG Energy to deliver 1,800 “ice batteries” to commercial and industrial buildings served by electric utility Southern California Edison (SCE). The units are expected to reduce air conditioning bills by up to 40 percent and eliminate 200,000 tons of CO2 over the next 20 years.

Ice Energy has been building ice-based cooling systems since the early 2000s. Much like pumped storage or compressed air “batteries,” Ice Energy essentially stores electricity by drawing power from the grid at non-peak times to freeze water in a special container. Then at peak times, when the cost of electricity is high and grid operators are struggling to keep up with demand, Ice Energy’s systems kick in and use that block of ice to cool the space that the air conditioning unit normally serves.


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  • (Score: 2) by requerdanos on Sunday May 07 2017, @01:46PM (1 child)

    by requerdanos (5997) Subscriber Badge on Sunday May 07 2017, @01:46PM (#505830) Journal

    A fair bit of California's electricity is from wind and solar, which are intermittent. If more electricity is being produced than is needed, the excess production goes to waste:

    On March 27[, 2016], a sunny day, some solar farms had to shut down because there was more power on the grid than Californians were using.

    ...These ice-making systems would instead do something useful with that electricity.

    Although that day was a Sunday and therefore classified as off-peak all day, most days, the summer off-peak use is going to be 11pm - 8am when the solar farms are already shut down. It seems to be basically an at-night system, which mostly rules out solar.

    Sources of electricity generation in CA [eia.gov] during the night-time seem to be Natural Gas, hydroelectric, nuclear, and renewables like wind, in that order.

    So what it seems is that, with solar off the table at night, a higher percentage of the energy available (by whatever margin) is going to be the creating-carbon-exhaust variety, and since the system can't be 100% efficient, it is going to use more overall energy than just running the air conditioner. (Instead of 'wasting energy'--if it's doing work it arguably isn't wasted--I should have said 'using more energy' above).

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  • (Score: 2) by butthurt on Sunday May 07 2017, @11:39PM

    by butthurt (6141) on Sunday May 07 2017, @11:39PM (#506059) Journal

    > [...] summer off-peak use is going to be 11pm - 8am [...] It seems to be basically an at-night system [...]

    The article says:

    What the utility gets in exchange for its discounts is control over when the IceBears are turned on and off [...]

    which seems to mean control over when the ice is melted. I see nothing that contradicts what you said; an earlier article says specifically that the units were intended to be run "at night"

    https://cleantechnica.com/2014/11/22/25-mw-ice-energy-storage-southern-california-edison/ [cleantechnica.com]

    Just as a conventional air conditioner can run during the day--albeit less efficiently than at night--these could run during the day if their controller had been designed to allow it. Again, I see nothing that says they were designed that way, which is too bad: solar energy used for freezing in the morning could lessen electric use in the afternoon and evening, when the load is highest in the summer:

    https://www.eia.gov/todayinenergy/detail.php?id=19111 [eia.gov]

    > [...] since the system can't be 100% efficient, it is going to use more overall energy than just running the air conditioner.

    You seem to disregard the last two paragraphs of my previous comment (#505638): cooling at night can be more efficient than cooling during the day; running a gas-fired (or coal or nuclear) power plant at full capacity around the clock is more efficient than using it for peaking. Overall energy ought to include the energy embodied in the natural gas. You seem to be considering just the electric energy used, which could be higher with the Ice Bear but not necessarily (because of the Carnot thing).