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(1) what estimate his Department has made of the de-rated capacity margins for electricity in each year since 1989 for which figures are available;
(2) what forecast his Department has made of the likely de-rated capacity margins for electricity in (a) 2013-14, (b) 2014-15, (c) 2016-17, (d) 2017-18 and (e) 2018-19.
The information is as follows:
The following table shows the Great Britain capacity margin for 1999-2000 to 2011-12. Figures for 2012-13 will be available on
|Capacity margin (GB de-rated major power producers capacity(1)/GB maximum demand) (percentage)|
|(1) Only wind, small hydro and solar PV capacity are de-rated in these figures, therefore they are not directly comparable with the estimate of future margins below. Source: Digest of UK Energy Statistics, tables 5.8 (GB capacity) and 5.10 (GB Maximum Demand), available at: https://www.gov.uk/government/publications/electricity-chapter-5-digest-of-united-kingdom-energy-statistics-dukes|
Estimated future margins
The Energy Act 2011 placed an obligation on Ofgem to provide the Secretary of State with a report assessing capacity margins into the future. On
Their assessment was that de-rated margins over the period would be as follows:
|De-rated(1)capacity margin (percentage)|
|(1) All technologies have been de-rated to take into account their expected availability at times of system peak, therefore they are not directly comparable with the historical margins above.|
More details on the Ofgem Capacity Assessment, including on the outlook for capacity margins in different scenarios, can be found in their report:
As required by the Energy Act 2011, DECC will publish a response to the Ofgem Capacity Assessment later this year.