Dáil Éireann Debate, Thursday - 5 December 2013
147. Deputy Michael Moynihan asked the Minister for Communications, Energy and Natural Resources if he will state the arrangements in place when wind speeds are low, reducing the power contributed by wind turbines to the national grid; the power source used when this occurs; the cost of this arrangement; and if he will make a statement on the matter. [52446/13]
View answerThe dispatch of wind generation is carried out within the regulatory framework for market and grid operational requirements. Under Statutory Instrument No. 445 of 2000 Eirgrid, the Transmission System Operator (TSO), is obliged to operate and ensure the maintenance and development of a safe, secure, reliable, economical and efficient electricity transmission system. As the TSO, EirGrid is responsible for managing electricity supply and demand in real time and controlling flows of power on the transmission system. Wind is afforded priority dispatch by the system operator in line with the Renewable Energy Directive 2009/28/EC. Thus, when wind is available, it is dispatched first onto the transmission system. When wind is low, other generation sources are used. These are gas, coal, hydroelectricity, peat, oil, diesel distillate and other smaller sources such as Combined Heat and Power (CHP); in addition, there are potential imports of up to 500 MW over the East West Interconnector. To ensure that this is done in an economic and efficient manner, EirGrid employs a unit commitment schedule to determine the dispatch order of other generation. The unit commitment schedule is determined based on the commercial and technical parameters submitted by generators on a daily basis. The commercial parameters submitted by generators must be cost reflective as per the bidding code of practice rules, which form part of the Single Electricity Market (SEM) rules. The unit commitment schedule establishes the most economic order for dispatching the generation needed to meet electricity demand. The cheapest generation type is dispatched first, then the next cheapest and so on until the system operator has enough generation to meet demand. In general, when wind is high and available to the power system, the production costs in the market are lower.
