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South Australia reaches record wind output of 1,540MW

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South Australia set a new record for wind output on Tuesday, the Anzac Day public holiday, reaching 1,540MW just before midnight – a significant lift on its previous record of 1,400MW set just two weeks earlier.

This graph below – from NEM-Watch – illustrates the huge surge in wind output on Anzac Day, which followed several instances over the previous few days when output was minimal at some points. At its peak, the wind output equated to 96.6 per cent of its registered capacity.

The Australian Energy Market Operator says it was forced to intervene to ensure that at least two gas-fired generators remained on line – and it imposed controlled pricing over the period to ensure that occurred.

south australia wind output

AEMO has been required to have at least two large gas generators working at all times under new rules imposed by the South Australia state government last year following the state-wide blackout in September and other rolling stoppages since then.

This graph below illustrates another view of events, this time from Dylan McConnell at the Climate and Energy Institute in Melbourne, which shows the total output from South Australia, including the various gas generators. The green below the line shows the exports at various times.

s.a output anzac day

It is interesting to note that the surge in wind energy in the late evening came just as the state’s electric hot water systems are switched on under their controlled load arrangements. This represents around 190MW of demand, and was timed to switch on then to give the coal generators something to do at night-time. They, of course, are now closed.  

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  • WR

    The second graph illustrates what I haven’t understood about the calls for storage being needed in SA because of there being too much renewable generation. I’ve never seen the output from the wind generators curtailed. There is always a large export market just over the border in Victoria to soak up any excess generation in SA.

    • Tom

      Unfortunately the limits on importing to VIC average about 220 MW out of a rating of 650 MW. The import limit can actually be positive i.e. flow must go into SA!
      This means that during high wind it is possible for the interconnector to be congested. Whenever SA has negative prices a wind farm is being curtailed.
      Hopefully Electranet get their second interconnector built soon.

      • Peter F

        Tom the Heywood link is 650MW and Murray Link is 200MW, how come they are not symmetrical. I have heard that is also the case in Queensland/NSW, what prevents them transmitting both ways

        • Just_Chris

          I think both interconnectors can run in either direction.There may be operation or political reasons why they don’t use both simultaneously to export to Victoria. I assume that you don’t run the interconnector at full power for any length of time but I don’t understand why they can’t export 500MW+ pretty constantly on windy days. At the peak in the second graph SA is exporting over 500 MW of power to Victoria.

          I think the calls for storage in SA relate more to power companies cornering the market and causing price spikes. 100 MW for 1 hour is not going to make a great deal of difference to the mix of generation when looked from an energy perspective 100 MWh is less than 0.5% of SA total energy use per day.

        • Tom

          Peter,
          There are other network constraints (thermal, voltage stability or transient) that limit how much the network on the other side of the interconnector can safely take.
          In QLD you can’t pump hard north because if Kogan Creek (largest single unit) tripped the interconnector would overload.
          Bottom line is that to be conservative and run in a safe state, you often give up some economic efficiency. Redundancy is the solution.

          • Peter F

            Tom
            I understand the Kogan’s Creek issue, Germany to France has the same problem when France overall can be short of supply but if the nuclear plants on the French side of the border are generating, then the capacity to send more German power via the interconnect to the French grid is restricted by the capacity of the grid west of the French power station.

            However I believe that the capacities of the SA Victorian interconnects are their continuous rating. I think Heywood reached about 850MW before tripping during the blackout. There would be a slight de-rating at 40C+ so perhaps max continuous capacity on a hot day might be 750-780MW. There are no large power stations near the state border so one would imagine that you should be reliably able to export 750-800MW to Victoria even if most of it only gets as far as Portland.

            This argument assumes the actual interconnects are symmetrical, does anybody actually know.

          • Guest

            The interconnects are not symmetrical. Murraylink is an HVDC system, Heywood is regular AC interconnect. The constraints are listed here at an export (SA to VIC) of 500MW

            http://www.abc.net.au/news/2017-01-20/blackout-investigation-puts-power-import-plan-on-hold/8195394

      • Ian

        Thanks for the insight, am I right to say the actual interconnector is direction agnostic, but the distribution on either side constrains the import and export flows? Should the capacities at either end not be improved to allow full transmission capacity of the interconnector. It’s just stupid not to fix this problem.

    • TheTransition

      Remember that Victoria has its own large renewable energy targets. To meet them, Victoria will need to install abut 4 times the wind generation capacity of SA. Something like 6 GW. The time scale for this build is quite short, less than 10 years. Large scale wind resources are quite correlated between Victoria and SA so when SA has 1.5 GW of Wind available, Victoria will have 6 GW. So there will be nowhere to consume the output of the SA wind farms unless it is stored for later.

  • Ian

    Interesting the periodicity of the wind resource. This is not diurnal but seems to vary from day to day. Perhaps this reflects the cold fronts which sweep across the Southern shores of Australia. Why not do a single graph showing wind generation for Tasmania, Victoria, South Australia and perhaps New South Wales over a typical week or month. These resources can be compared apples for apples with a y-axis variable of the total wind generation / total wind nameplate capacity as a percentage . One of the ways suggested of smoothing out wind energy production is to share this resource over a wide geographic area. Well such a modification of the first graph, may be perfect to illustrate this concept.

    Most likely there will be wind blowing somewhere and probably not everywhere or nowhere, therefore connect all these wind resources, so at least we can all get some wind energy all the time. This is a reasonable hypothesis to make but is it born out in fact? Should we bother with a robust system of interstate transmission lines if the wind resource is very close to being the same everywhere in the NEM area?

    Gas is supposed to be dispatchable but it seems to be given preference inSouth Australia. Is that purely to appease the gas generators who have milked the system previously to make a quick buck out of the high bidding periods, or is it because these generators cannot ramp up and down quick enough to provide peaking generation, or is it that they are not economical unless run continuously?

    • Just_Chris

      Careful planning of the location and size of our renewable energy assets is something I always wonder about as well. As you rightly point out, if it is done properly you could conceivably reduce variability quite significantly but, as people never really talk about, if you stuff all the renewable energy into one location then you must be asking for trouble. My understanding is that Hornsdale is a particularly good place for a wind farm because its wind resource is driven by sea breezes rather than weather fronts. The theory being that Hornsdale is windy in the morning and evening during peak power usage times whilst other wind farms produce lots of power one day and then nothing the next. I am sure it is more complex than that but it seems to make sense to me that we should have a greater spread of wind and solar farms across the country.

      Just looking at the wind speeds today:

      Adelaide 13 km/h
      Melbourne 23 km/h
      Sydney 21 km/h
      Hobart 16 km/h
      ACT 18 km/h

      that seems a pretty good spread. Does anyone have a link to a study that has looked at this? I’m sure it must have been done.

  • alexander austin

    does anyone know how the price intervention during the period when the gas fired generators were forced to be one works? Did this effectively stop the pool price in SA from being negative (as otherwise there was more wind than demand)?

  • heinbloed

    Great news!