Spatio-temporal analysis of possible wind generation output reductions for the Irish transmission system with a high penetration of renewables

This paper outlines a modelling methodology utilised by EirGrid, the Irish Transmission System Operator, to apportion reductions in the electricity production of wind powered generators due to a variety of security of supply issues and localised transmission congestion. Studies addressing security of supply set a limit for non-synchronous generation such as wind, to between 50% and 75% of the total system generation (demand plus exports) over the period 2011-2022. The potential impact of a possible 75% maximum instantaneous wind penetration limit on the small, synchronous and relatively-isolated Irish transmission system by 2020 is assessed. Ireland is expected to achieve the majority of its 40% renewable target in electricity from wind and there will invariably be instances when the amount of wind generation will be greater than demand. This should also be seen in the context of transmission congestion where wind generation connects on a non-firm basis prior to completion of their deep assets. Both of these issues lead to reductions in the output of wind generators and these reductions are presented in this paper, together with the description of the innovative and novel methodology used to determine these reductions.