Wind Energy in the United Kingdom: Modelling the Effect of Increases in   Installed Capacity on Generation Efficiency
  The decision by the United Kingdom (UK) government in 2007 that the country should build a 33GW wind fleet, capable of generating 25 percent of the UK electricity requirement, was controversial. Proponents argued that it was the most attractive means of lowering the UK greenhouse gas emissions, whereas opponents noted that it would result in an unnecessary and burdensome additional expense to industry and households. Subsequently there have been calls for the wind fleet target to be further increased to perhaps 50 percent of demand. Although the National Grid has had little difficulty in accommodating the current output of about 10 percent of the total demand on the grid, this will not be the case for a substantially larger wind fleet. When the wind blows strongly, turbines shed wind which is surplus to demand, leading to significant reductions in generating efficiency. The purpose of the research described in this paper has been to develop a method for investigating the likely performance of future large wind fleets. The method relies on the use of mathematical models based on National Grid records for 2013 to 2015, each year being separately analysed. It was found that the incremental load factor of the wind fleet will be reduced to 63 percent of its current level should the wind fleet increase from its current size of 14GW to 35GW, assuming a base load of 15GW 
Anthony D Stephens and David R Walwyn
physics.soc-ph