Solar pushes Qld network peak into evening in G20 heat

Here is an interesting graph that showed what happened with the electricity load in south east Queensland at the height of the heatwave that hit Brisbane and surrounds during the final day of the G20 meeting.

Being a Sunday, there was not a lot of commercial and industrial load, but the residential load was heavy as households fired up the air-conditioning. (Queensland has more than 90 per cent penetration of air-con, and about 25 per cent penetration of rooftop solar).

This graph is remarkable because it shows what nearly 900MW of rooftop solar capacity on the Energex network in south-east Queensland does to the peak – instead of being around 4pm it is pushed to 7pm. Both the height and the length of the peak is changed. South Australia, the other state with as much solar, has also recorded similar changes, much to the approval of the grid operator.

That has changed the equation for those generators that used to rely on big peaks – and very high prices – to provide a big slice of their annual revenue (some 25 per cent in just 36 hours of peak power according to some calculations).

But it also highlights the challenge to the grid. Solar detracts from energy consumed, and while it is succeeding in delaying the absolute peak, it is not removing it. Once it can do that – presumably with the assistance of battery storage installed by either the household or the grid operator – then the equation will change dramatically, and servicing the peaks will no longer be the massive cost burden that it has in the past, and still is.

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Comments

6 responses to “Solar pushes Qld network peak into evening in G20 heat”

  1. john Avatar
    john

    Peak which has shifted to late afternoon-evening just where the use of storage will be of most use, is coming.
    I feel even at $800 a KwH that it is a payable situation that beats bank interest

    1. suthnsun Avatar
      suthnsun

      They want more than bank interest (justifiably ) but your point stands, the amount of storage required per consuming unit is very small and the peak would be quashed. Throw in some intelligent demand response and thermal storage and the peak will not be an issue. In the old days( before ‘gold plating’ and ‘robust networks’) the peaks were survived over far longer periods with far less equipment. As long as vulnerable points get a chance to dissipate heat overnight it’s hard to see how the system will ever be stressed again.. who will foot the bill for the overcapitalisation ?

      1. john Avatar
        john

        The end user has and is paying for the overcapitalisation.
        Energex being in SEQ area has mostly urban clients who turn on the ac and cook dinner and have a shower between 4 and 9 pm
        I feel they will move to supply storage so they have an ongoing business plan.

  2. SolarPowerBen Avatar
    SolarPowerBen

    The title of this article is very misleading. A proper discription of what’s happening would be to say: Solar PV can cut back the peak if it occurs during periods of sunshine. If the total power consumption of the community is higher than the cutback effect of solar PV the resulting peak may occur after sunshine hours.

    This is very nicely shown on page 27/28 of the Energex Distribution Annual Planning Report 2013/14 – 2017/18 (https://www.energex.com.au/__data/assets/pdf_file/0003/167304/DAPR-2013-14-to-2017-18-Volume1.pdf)

    Also, to say that “Solar detracts from energy consumed” is misleading too. It is not Solar, but the net feed in tariff (fit) as opposed a gross fit. In a gross fit system all network operators can gather data about all power produced and consumed, in a net fit system that is not the case because power consumed in a solar PV place needs to be drawn from the PV system before more power may be imported. this hides the exact circumstances, whether a high consumption event is taking place during times of high production or a low consumption during an e.g. cloudy moment.

    The graph above including accompanied text suggests that Solar PV actually shifts power peaks while consumption volume remains equal. What actually happened is that consumption has risen strongly and the comparatively small rise in Solar PV can’t completely compensate, certainly not after sunset.

    Lastly, to suggest (in the graph) that Solar PV power generation is directly linked to outside air temperature is simply false.

    Overall, however, a great case for power storage at the location of power production!

    1. Matthew Wright Avatar
      Matthew Wright

      Solar is actually clipping the peak after sunset. That’s because it is pre-cooling all the equipment by running it at lower utilisation. It really heats up when it is getting towards capacity limits. In fact the equipment ratings are really just thermal ratings.

  3. WA David Avatar
    WA David

    It is poor style to put a chart up comparing a Saturday with a Sunday, when trying to show the effect of PV on the load profile. This is even more pertienent after the author already stated that commercial and industrial load would be less on a Sunday.

    Further, in the scheme of things, the amount of PV installed on the two days plotted would be very similar, so any differences observed are probably largely due to the day of week and the fact that having the city shut down (for the G20) would be highly atypical. Thus the plot is actually comparing a (maybe) typical hot Saturday, to a highly atypical hot Sunday with about the same amount of PV installed.

    Assuming, that we actually had this plot resulting with a hot Sunday Vs hot Sunday, the resulting difference would be largely due to the G20 effect (removal of commercial load that operates 9am-5pm).

    P.S. I have not doubt that PV played its (large) part in getting the resulting load profile, its just that this plot does not illustrate this at all.

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