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Joined 11 months ago
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Cake day: June 3rd, 2024

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  • We’ve got some large scale batteries in SA (funnily enough one of our first was built by Elon, with his ‘$100mil for 100MW in 100 days’ promise, which largely held- this was pre mask-off though) and it’s now a lot better than in was in 2016.

    We’ve also got more power generating here, so less variable dependence on interstate links (which go back to Brown Coal powered Victoria, yuck)

    I’m not implying there is a problem with their grid though, just stating a small problem can cascade very quickly in an AC grid, it doesn’t take a lot especially when a lot of us in the western world have been belt tightening for the last 10-15 years (less available backup capacity)


  • 10 seconds of rotational momentum stored in turbines, such that if there is a skew in the balance of electrical supply:demand it will ‘sap’ that rotational momentum before the frequency starts starts dropping. Once that energy is depleted frequency will drop, in SA 1hz (from 50hz) is enough to trigger UFLS (‘Ultra fast load shedding’ - not fast enough for .6s momentum though) which will start dropping parts of the grid to try and keep at least part of it alive (restarting from a black system takes a lot longer than sequentially just adding de-energised parts back)

    ‘large spinny things’ - These don’t need to be big generators, they they can just be dyanmos (or better we start to move to a DC grid and just use capacitor banks.)


  • That’s all it takes some times if conditions are bad inside a grid.

    This is one of the unfortunate downsides to moving form ‘large spinny things’ in coal generation to tiny integrated circuits generating the rotational momentum needed in an AC system. We had a similar issue in South Australia in 2016, complete black system after a number of events but of the two biggest preventable causes, one was simply the loss of rotational momentum in the system, in 1995 is used in be close to 10s, in 2016 it was less than .6s

    We need to start rethinking the grid for the future, we can’t keep coal/gas but we also can’t keep a grid completely reliant on momentum for short term ride through.