Wind energy supplies 20% of south-east states demand over one week

Prolonged strong winds have dominated the weather across south east Australia for more than a week. Unsurprisingly, the winds have enable wind generators to set new output records. Not only was the highest ever 5 minute despatch level set on Tuesday morning of last week, as reported by Paul McArdle, but new records have been set for total daily generation.

On Sunday 11 May 68.7GWh were generated in total, surpassing by a wide margin the previous highest daily total of 62.0 GWh set in June 2014. Saturday 10 and Tuesday 5 May also broke the old record.

Sunday’s wind generation was equal to 15 per cent of total generation sent out in the NEM and equates to a wind generator capacity factor averaging 79.5 per cent for the whole day. It was also 15 per cent of total sent-out NEM generation on that day.

New records have also been set for continuous seven-day output, with wind generation over the week from Tuesday May 5 to Monday May 11 totalling 11.6 per cent of total NEM sent-out generation, with a wind generator capacity factor averaging 67 per cent over the period.

This quantity of wind generation resulted in the displacement of roughly 400 kt of greenhouse gas emissions, assuming that the wind displaced a mix of brown and black coal generation.

But to think about what new renewable generation could achieve if Australia were actively seeking to decarbonise its energy supply, it is more instructive to look at the three south east states of Victoria, SA and Tasmania.

All three states have a significantly higher share of wind relative to total generation and demand than NSW (there is negligible capacity in Queensland) and they are where over 80 per cent of NEM wind capacity is located.

Tasmania and Victoria (including Victoria’s share of Snowy output) also account for most of Australia’s hydro generation (around 80 per cent in most years). Hence, notwithstanding brown coal generation in Victoria, these three states together are further down the road to decarbonisation than either NSW or Queensland (or, for that matter, WA).

Wind supplied more than 20 per cent of electricity consumed in these three states for much of the period and the total renewable share above 30 per cent for the entire period since early on Monday, May 4. It was above 50 per cent for much of the morning of Sunday May 10, and again form some hours overnight on Monday, May 11.

One interesting fact in the data is that demand was significantly higher over the weekend of May 9-10 than over the preceding weekend, presumably mainly because the weather was much colder and windier.

Winter peaks in the NEM nearly always occur on wet windy evenings in June or July. Hence, for the generation part of the total electricity supply system, wind is, as it were, counter-cyclical, i.e. it meets the demand it creates.

In fact, comparing the past two weekends, wind generation over-delivered spectacularly. On Saturday May 9, total demand (net of thermal power station auxiliary loads) was 7.1GWh higher than on the preceding Saturday, but total wind generation was 24.9GWh higher. The corresponding figures for the two Sundays are 9.4GWh more demand and 52.9 GWh more wind generation.

Hugh Saddler is the senior energy analyst at Pitt&Sherry