This page gives information on the peak electricity consumption of the GB grid.

Note that consumption is not the same thing as demand. A substantial and rising amount of consumption is being met by distributed generators such as wind, solar and biomass, the remainder being the demand on metered generators. Since embedded wind power is highly variable from day to day, it is necessary to separate it from other distributed power, and this is done via a quantity called “Residual Consumption”:

  • Residual Consumption = demand + embedded-wind-power

“Residual Consumption” is the total consumption not met by other (non-wind) distributed generators. The National Grid estimates the amount of embedded wind power at 30-minute resolution and provides the information to the public in its “demand” data files, see the NATIONAL GRID DATA page of this blog for more information.

History of Winter Peak Consumption

The following figure shows recent historical data for winter peak residual consumption, derived from data available from National Grid, showing only the months of December, January and February:


The data above is very important for determining the expected peak consumption in future winters.

It appears from the figure above that residual consumption is falling. Some of that falling trend is probably due to the increasing amount of distributed generation, and by several economic influences, but note that the three most recent winters have been exceptionally mild, which has probably exaggerated the falling trend in recent years.

Seasonal Profile of Peak Demand

The following figure shows the daily peak demand for the entire year of June 2011 to May 2012:


Regular dips at weekends can be seen in the figure above, together with more substantial ones on Christmas and New Years days.

Demodulation of Consumption

To provide good estimates of how much electricity may have to be generated in winter it is necessary to “demodulate” consumption data, because high peak demands may not be realised simply because they fall at weekends or during holiday periods. I do this demodulation by temperature-guided interpolation across weekends and holidays, using the data on nearby working days to set levels.

Peak Consumption of Recent Winters

The following figure shows the daily peak residual consumption (demodulated), November to February, for each of the past 11 winters, the ones for which National Grid data is readily available:


The figure above shows the lower peak consumptions of recent winters, some of which were almost “flat”, reflecting a run of mild winters without major freezes. The data from the individual winters are shown again in the following series of figures, which also show a representative temperature for GB, chosen to be the mean of the Central England Temperature series (HadCET). The data shown below are used in this blog for the following purposes:

  • To assess the maximum rise in consumption across the winter period
  • In assessments of the extra reserve capacity provided by wind power


Further details of winter 2005/06:


Further details of winter 2006/07:


Further details of winter 2007/08:


Further details of winter 2008/09:


Further details of winter 2009/10:


Further details of winter 2010/11:


Further details of winter 2011/12:


Further details of winter 2012/13:


Further details of winter 2013/14:


Further details of winter 2014/15:


Further details of winter 2015/16:


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