The previous post gave a quantitative estimate, for the GB electricity grid, of the wind power at peak demand time expected in 2016/17 if there is a repeat of the recent coldest winters. This post extends the analysis back to the winter of 1995/96, again with particular interest in the wind power expected on the coldest (highest demand) days.
We saw in the previous post that whenever the estimated wind power was low the synoptic chart for the day in question confirmed the estimation from the wide spacing of isobars. In this post the synoptic charts are used directly to provide a qualitative assessment of the amount of wind power expected.
First of all the coldest days were identified for the winters between 1995/96 and 2006/07, via a threshold of zero degrees C applied to the daily maximum of the Central England Temperature (HadCET) series:
The figure above identifies 3 relatively cold winters: 1995/96, 1996/97 and 2005/06, with cold days as follows.
27/28th December 1995. This winter had one very cold day (28th December) with a maximum temperature of -3C, which would have resulted in a substantial rise in demand for electricity, but with relatively low wind power, shown by the following synoptic chart:
Note that the colours in the figure above represent pressure, at an altitude where the pressure is around half its typical surface value.
Half-hourly weather data measured at Cambridge confirms the very low temperature of 28th December 1995, as well as the light winds (and absence of sunshine):
January 25/26th January 1996. The following synoptic chart reveals that this was a relatively windy cold spell:
February 6th 1996. The following synoptic chart reveals that this was a relatively windy cold day:
December 31st 1996 – January 1st 1997. The following synoptic chart reveals that this was a relatively windy cold spell:
January 1st 1997. The following synoptic chart reveals that this was a relatively calm cold spell:
Winter 2005/06: February 2nd 2006. The following (surface) synoptic chart reveals that this was a relatively calm cold spell, with light winds across most of Western Europe:
Wind power at 2016/17 levels would make substantial contributions to meeting peak demand for some of the cold spells examined above, but not for all of them. The coldest spell had light winds across the UK, and this cold spell must be added to the list of similar ones in other periods, and must be catered for by the GB electricity system in forthcoming winters.