A recent 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 1985/86, again with particular interest in the wind power expected on the coldest (highest demand) days.
We saw in the analysis of recent winters 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 1985/86 and 1994/95, via a threshold of zero degrees C applied to the daily maximum of the Central England Temperature (HadCET) series:
The HadCET page of this blog allows the temperatures in this period to be seen in the context of the entire HadCET Tmax record, which extends back to 1878 (this analysis still has a long way to go!). The figure above shows one spell of severe cold weather, in 1987, and this is described in a separate post. The remaining cold spells are discussed below.
December 28th 1985: The following synoptic chart indicates light winds (low wind power):
February 6th – 21st 1986: There was a wide variety of wind speeds in this period, ranging from LIGHT to WINDY:
Winter 1986/87: This spell of severe winter weather is covered in a separate post (TBD)
Winter 1990/91, February 7-9 1991: Moderate winds brought cold air, but the winds died away (as they always do), leaving cold conditions with relatively light winds on 9/10th February:
Winter 1991/92: December 11/12th 1991 were cold calm days:
December 29th 1992 was a cold calm day:
January 2nd 1993 was a cold day with some wind, especially in Scotland:
November 23rd 1993 was a cold day with light winds:
February 14th 1994 was a cold day, with a Scandinavian High giving Easterly winds:
This period had a mix of cold-calm and cold-windy days. UK electricity consumers need to worry most about the cold-calm days, as wind power may be low, and dispactable power may be insufficient to meet peak demand. The cold-calm days from this analysis will be combined to assess how much dispatchable power is required.