This is No. 11 in a series of posts that look at GB Wind Power, in particular at its ability to contribute to peak demand, which occurs in the early evening, reaching its highest values during winter cold spells on working days. This post shows estimates for how much wind power would be produced if the 2016/17 wind generators encounter the weather conditions of the winter of 2010/11. Of particular interest is the wind power produced on the coldest evenings, quantified via the increase in minimum reserve capacity relative to a hypothetical no-wind system.
There is no need for me to describe this particular winter as the job has been done already by the UK Met Office, due to its severity:
The following figure sets the scene for the detailed analysis, showing hourly temperatures measured at Northern Ireland for the entire cold period. Does the current GB electricity system have sufficient capacity to deal again with this weather, especially if it is shifted by a week or two away from the low demand Christmas holiday period?
My Analysis
The objective is to see how the GB electricity system of 2016/17 would respond to this weather. Data at 30-minute intervals for demand and “Estimated Embedded Wind” in winter 2010/11 were downloaded from National Grid and used to estimate “Residual Consumption” in 2010/11, and total wind power (both metered and embedded) at 2016/17 levels. “Residual Consumption” is the name given here to the sum of demand and embedded wind, and represents the consumption not met by other (non-wind) distributed generators. Metered wind power for 2016/17 is estimated by scaling up the embedded wind power data to the typical levels seen for metered wind in late 2016. Embedded wind is scaled-up according to its total capacities in 2010/11 and 2016/17. See the NATIONAL GRID DATA page of this blog for a discussion of the accuracy of these estimation techniques.
The figure below shows the daily peak “Residual Consumption” (in red) and the estimated 2016/17 total wind power (metered plus embedded), for the winter weather of 2010/11:
The figure above shows the expected characteristics of GB wind power in winter 2016/17: it will be intermittent, it will be small compared with peak demand, and on some days it will almost vanish at the time of peak demand. To see the amount of wind power at the times of highest peak demand the data are plotted again in the figure below, with an arbitrary offset of 62 GW applied to the demand data. The 62 GW offset is indicative of how much dispatchable power was needed in 2010/11 to meet peak demand. The figure also shows the mean temperature of the Central England Temperature (HadCET) series:
The consumption data shown in the figure above (red curve) has been demodulated, by temperature-guided interpolation across weekends and the Christmas/New-year holiday period. The following figure shows the demodulation of the important period, with the cold spells:
The figures above shows that there were two spells of cold weather, one in late November to early December, and another one in mid to late December. To show more clearly the contribution of wind power to peak demand the following figure shows “Reserve Capacity”, for the arbitrary (though not unrealistic) choice of 63 GB of dispatchable supply, with and without the contribution of wind power:
The figure above shows that wind power at 2016/17 levels would provide an extra 1.0 GW of reserve capacity for this weather, reaching this minimum value in both cold spells, on what must have been days with light winds, since 1 GW is only a small fraction of the 15 GW of total wind power in 2016/17. To help to confirm the light winds the following figure shows the half-hourly weather conditions measured at Cambridge for the entire cold period:
Further confirmation of light winds is provided by the following synoptic charts for 7th December 2010:
and 20th December 2010:
Other Analysis
National Grid provides the following plot of metered wind power output in 2010/11, confirming its low output at the times of peak demand:
Source of the figure above is Figure E4 of the 2011/12 Winter Consultation report, available here: http://www2.nationalgrid.com/UK/Industry-information/Future-of-Energy/FES/Winter-Outlook/
Conclusions on the contribution of 2016/17 wind power to the highest peak demands will be drawn elsewhere on this blog, in conjunction with the results of other winters.
