The following graphs contain the actual electricity demand and actual wind energy demand curves for 16th February 2007 for Ireland. The third in the series plots the percentage of the national grid that was supplied on that day by wind energy. The raw information was downloaded from the archives of www.eirgrid.com, the Transmission System Operator (TSO) in Ireland.
You can see that wind production went from nearly 20% of demand to almost 0% of demand in one day and worse of all was the fact that it did so completely out of sync with the demand usage curve. Wind energy supply and electricity demand were not matched. This mismatch creates difficulties for network operators because, apart from limited pumped hydro storage capability, electricity cannot be stored and it takes time to start and stop fossil fuel burning electricity burning stations. Also, because of the unreliability of supply, it is necessary to have enough non wind based capacity to meet maximum demand.
Despite the green credentials of wind energy there are problems with its implementation. If wind energy production, in Ireland, is to rise higher than its current 4%. We will have to implement either pumped hydro storage or demand management. Demand management is cheaper and faster to implement and I believe it is the necessary option for Ireland. Perhaps there is a place for pumped hydro storage also.
Current pumped hydro storage capacity in Ireland.
As far as I am aware, there is only one pumped hydro storage facility in Ireland. This is located at Turlough Hill http://www.esb.ie/main/about_esb/history_turlough.jsp
Current demand management projects in Ireland.
The following pdf presentation gives an overview of current EDM schemes in Ireland.