Cheap, Reliable, and Renewable

(or How Not To Run An Electricity Grid)

Here are some plots from the National Electricity Market (NEM) for the month of June which may illustrate the problems we will continue to face.

Figure 1: June consumption: all sources (Gigawatts)

Note the dip in consumption every weekend.

Figure 2 shows the relative contribution of all major sources, (but including battery, if you can see it).

Figure 2: June consumption as a percentage of total: all sources

You may note that coal stepped up mid-June to produce 60% of all electricity.  The contrast with all other sources is obvious.

The next plots show June monthly average, maximum, and minimum for all major sources.

Figure 3: June consumption Average, Maximum, Minimum

Note that while coal ranged from about 300 to 350 GW, wind ranged from almost half coal’s minimum to very little.

Figure 4: June consumption Average, Maximum, Minimum as percentages

Coal stands out for its consistency.  And with all the rooftop solar and solar farm expansion, solar cannot produce 10% of our power needs.

The next figures compare coal with renewables to show the daily fluctuation, that is, how much the electricity generated (and consumed) each day compares with the one before.

Figure 5: Percentage daily change in electricity consumption: coal and total

The close match between coal and total consumption is obvious.  Coal’s daily percentage changes (above that of the total) on the 2nd, 13th, 16th, 17th, 18th, 21st, and 30th June correspond to the fall in renewable generation – especially wind- on those dates, as Figure 6 shows for coal and wind.

Figure 6: Daily change in coal and wind consumption (Gigawatts)

The contrast is even starker when expressed as a percentage:

Figure 7: Daily percentage change in coal, wind, and solar consumption

Coal can change on a day to day basis by 20 to 30 percent.  Wind can decrease by 76 percent or increase by 326 percent from one day to the next.  What a way to run an electricity grid!

One thing you can say about renewables: they can be relied on to be unreliable.

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3 Responses to “Cheap, Reliable, and Renewable”

  1. John in Oz Says:

    If only the politicians and pro-renewable lobby could understand this and stop saying that more renewables will ensure reliable power.

    Keep up the good work

  2. tonyryan43 Says:

    Off-topic, but in front of everybody’s minds, why has the Wet continued unabated in the Top End… frequent rain, daily grey skies, and we are now into July?

  3. Cheap, Reliable, and Renewable: July 2022 | kenskingdom Says:

    […] to illustrate the problems we continue to face. Figures 1 and 2 are updates of similar figures from June, but Figures 3 and 4 are new and hopefully show the problem even more […]

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