South Australian response today to 2013/14 weather

Summary

The AEMO uses past wind power and demand data to model the future adequacy of the NEM, and they make the data used available to the public. This post presents some of the data available for the summer of 2013/14, of particular interest because of a major heatwave in South Australia that caused peak demands greater than 3000 MW.

The focus of this post is on the amount, and on the impact, of wind power that would be produced today if there was a repeat of the summer weather of 2013/14. No attempt is made here to adjust the actual demands of 2013/14 to the present time.

The estimated wind power that would be produced today from the 2013/14 weather is found to reduce peak demands on non-wind sources of electricity by around 200 MW, around 10 MW for each of the 18 wind farms. In common with other years examined the impact on this figure (200 MW) of additional wind power is very small, because the large amount of existing wind power pushes many of the non-wind peak demand times to deep wind lulls, such that adding another wind farm to the 18 already present would reduce the highest non-wind peak demands by only several MW.

Increasing wind power in South Australia will have a large impact on the economic viability of non-wind sources, whose market share is reducing, but at the same time cannot reduce the need for around 3000 MW of firm capacity for the foreseeable future.

Data Sources

The AEMO has done the estimation of wind power from past weather, using actual measured data for the wind farms present at the time, with interpolation/extrapolation for recent additions, for example all 3 Snowtown wind farms are assumed to have identical capacity factors. The resulting data is called “Wind Traces” and can be downloaded from here:

https://www.aemo.com.au/Electricity/National-Electricity-Market-NEM/Planning-and-forecasting/NEM-Electricity-Statement-of-Opportunities

Demand data is used from a different source, the actual historical demands available from here:

http://nemweb.com.au/Reports/ARCHIVE/HistDemand/

Demand Data

The following figure shows the daily peak demands (blue curve) and the two major influences on them, the maximum temperature (at Adelaide Kent Town) in red and the times of weekends and holidays, marked with purple dots:

The figure above shows several heatwaves, the one from 13th to 17th January being particularly long and hot and producing a major spike in peak demand.

Wind Power

The AEMO-estimated total wind power today from the 2013/14 weather is shown in the following figure, in terms of the daily maximum (red) and minimum (black):

The figure above shows the typical wind power variations in South Australia, often going from very high to very low in many days of summer. It is the deep wind power lulls, many lower than 50 MW, that causes the severe limitations on the impact of additional wind farms on peak demands on non-wind sources. The wind power data provided by the AEMO are 30-minute averages, and the minima will go to even lower values than shown above at times during each 30-minute interval.

Wind Power Impact

The following figure shows the daily peak demands (red squares), and the peak residual demands on non-wind sources (black curve):

The figure above shows that the highest peak demands on non-wind sources would be reduced by around 200 MW, i.e. by only around 10 MW for each of the 18 wind farms. A simple way of seeing the impact of additional wind farms is to repeat the calculation of non-wind peak demands (black squares) with 50% more wind power (purple curve), shown in the following figure:

The figure above shows the barely perceptible effect of 50% more wind power on peak non-wind demands. The deep wind lulls of around 50 MW are the explanation, as they imply that each of the 18 existing wind farms are averaging a contribution of only several MW at the times of highest demand on non-wind sources.

Increasing wind power in South Australia will have a large impact on the economic viability of non-wind sources, whose market share is reducing, but at the same time cannot reduce the need for around 3000 MW of firm capacity for the foreseeable future.