Wind watch and the choke points revisited

Reporting on the contribution of the windmills at the evening peak of demand from early December. The point is to demonstrate the significance of the lowest levels of wind supply (choke points) when they coincide with peak demand in the morning and evening (breakfast and dinner).

This display shows the daily cycle and the contribution from different sources.

Some features of interest.  Black coal is the foundation of the system and it ramps up and down between 9.2 and 16.1. These are the limits that I have seen since I started to take notice. The peak is almost twice the level of the trough, a vivid indication of the efficiency (and profitability) that are lost by making coal stand in line behind the more expensive and subsidised unreliables that get first access to the grid. Brown normally runs steady and does not adjust to track demand like black coal, water and gas.

Water has capacity up to 5 or more but lately it has spent a lot of time at 0.5 presumably to husband the supply of water in the dams

Extreme heat is expected today and we are warned that problems at Loy Yang (brown coal) persist and also one of the four 500MW units at Liddell will close for repairs. Loy Yang went down in May and from that point the Brown Coal supply ran steady at 3.1GW until it came up in December and peaked at 4.6 at 4pm on Christmas Day. Since then it has been up and down with the latest changes in the last day when it dropped suddenly from 4.2 to 3.6 at 8.15pm last night, then eased up after midnight to reach 4.2 in the early morning and run steadily since then (fingers crossed).

On the bright side, there is less demand in the weekend.

Choke Points

The wind supporters talk in terms of installed capacity, sometimes allowing that the average is a good deal less (like a third)  but the real crunch is the minimum. We breathe air containing 20.95% oxygen most of the time (a bit less in crowded spaces) but when we are choking or under water we are dead in five or ten minute. Similarly the grid needs a constant supply of power or bits of it will die by managed or unmanaged load shedding and in the worst case (SA 2016) large parts will die.

This display shows the variability of the wind supply in December expressed as the percentage of installed capacity. The data points are three hour intervals. The range is 64% to 4.1% and the  average is a  bit over 30%

You can also see the picture for the amount of power with the range from 4.4GW to 0.273 but the default is the percentage and you can toggle to the volume. The installed capacity is 6.7GW so the average is about 2.2GW. Compare with Liddell (coal fired) at 1.7GW.

The Wind Contribution at the Evening Peaks

From 8 December the daily figures for the % of demand provided by the wind at 6.30pm (NSW Vic and Tas)  are

7, 7, 9, 10, 10, 11, 5, 12, 4  (and 2% at noon), 3.5, 5, 6.5, 10, 8.5, 7.2, 8.5 (2.8 at  noon), 11.5, 9, 6.5, 5.5, 4, 10, 7, -, 5.5, 6.

What happens when we lose Liddell or any other coal-fired power station?

Before Daniel Andrews put Hazelwood out of business there was a slim reserve most of the time to cater for really difficult periods. Since then we have been running on the rims and the danger of the situation has been obscured because there has been just enough power most of the time, give or take occasional blackouts.

Take out the best part of 2GW and then what happens at the evening peaks.

Adding another 7GW of windpower translates into less than one GW if the system is running under  10% of plated capacity or less and you can see from the display above that situation arose nine times in December. Of course there are times when it runs well below 10% (say 2%) but in the larger scheme of things under 10% is next to nothing when demand is peaking.


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9 Responses to Wind watch and the choke points revisited

  1. RobK

    The choke points imply a need for redundancy to cover for expensive storage. Then to counter this cost proponents wish to establish a H2 storage system for export.
    H2 is presently most economically made from fossil fuels. Somehow a massive leap in logic justifies an upto 700% redundancy of RE to underpin a H2 industry which is hoping to establish a footing on fossil fuels.

    ARENA chief executive Darren Miller joins the Energy Insiders podcast to discuss the potential of renewable hydrogen if it can replace the LNG market, and why 700GW of wind and solar may not be beyond the realm of possibilities, That wouldn’t be 100% renewables, it would be 700% renewables, and the side-product would be an abundant supply of cheap wind and solar power for the domestic economy.”
    As a aside, I have a sister in canberra who mentioned that the solar panels seem to languish in the smoke haze.

  2. Rafe Champion

    Sorry if any comments got lost, I managed to have two versions of the post and updated the wrong one so the other was lost.

  3. Bruce of Newcastle

    Victoria and SA current wholesale power price is minus one cent per MWh.

  4. Rafe Champion

    Thanks Bruce, I wanted to mention that display to track the movement of power between states.

    A bit of good news from cohenite on the open thread. The Indian Ocean dipole has broken down and this promises some relief from the recent spell of hot and dry weather.

    This prolonged and strongly positive Indian Ocean Dipole helped cause unusually warm and dry weather in Australia between winter and early summer, exacerbating the drought and helping bushfires burn across eastern Australia.

    While Indian Ocean Dipole events usually dissipate in late spring, the strength of this episode allowed it to persist well into summer. However, the latest weekly index value has dropped to neutral territory for the first time in months.

    While this doesn’t mean the weather in Australia will change abruptly, it does take this dominant climate driver out of the equation as we head into the new year.

  5. Roger

    Anyone who keeps an eye on the AEMO dispatch data would be astonished at how – ahem – close to the wind we are sailing with the eastern grid.

    It would apear only demand management and reserve power sources that AEMO can call on are keeping the grid functioning in periods of high demand.

    Something has to give at some point.

  6. Art Vandelay

    Something has to give at some point.

    NSW wholesale prices currently at $14,700. They just mentioned on the cricket that fires have cut an interconnector with vic?

  7. Roger

    NSW wholesale prices currently at $14,700. They just mentioned on the cricket that fires have cut an interconnector with vic?

    Time to fire up the gas plants at enormous expense.

  8. NuThink

    This is in addition to the giant diesels that SA has after the Big Blackout of a few years ago.
    I notice that they do NOT mention the type of fuel used by the new reciprocating engines.
    What fuel could it be?
    What fuel could it be?
    What fuel could it be?

    It seems that it is forward to the past.

    In July 2017, we announced a $295 million investment to develop a 210 MW reciprocating engine power station, the Barker Inlet Power Station. This station would sit alongside our Torrens Island Power Station site near Adelaide, South Australia.

    The Barker Inlet Power Station will comprise 12 reciprocating engines capable of generating approximately 18 MW of output each. The engines operate at high efficiency and with a lower heat rate than other forms of fast-start plants currently available. The station will also be capable of operating at full capacity within five minutes, providing a rapid response to changes in renewable generation supply.

    Full operation of the power station is expected late 2019.

  9. Rafe Champion

    Nu Think that looks too cheap, only 1.2 Bil per GW, can that be correct? What do they cost to run?

    How much did they need to spend to keep their last coal-fired power station running?

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