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    means a warm Warmth State.


    Warm Cooling Boundary

    means the period of time, which must be greater than that defined by the Hot Cooling Boundary, post Desynchronisation of a Generator Unit after which the Generator Unit’s Warmth State transfers from being Warm to Cold.


    Warm Start

    means any Synchronisation of a Generator Unit that has previously not been Synchronised for a period of time longer than its Accepted Hot Cooling Boundary and shorter than or equal to its Accepted Warm Cooling Boundary.


    Warm Start Up Cost

    means Start Up Costs associated with a Warm Start.


    Warmth State

    means either cold, warm, or hot, dependent upon the period of time which has elapsed post Desynchronisation of a Generator Unit relative to its Hot Cooling Boundary and its Warm Cooling Boundary.  Up until the Hot Cooling Boundary, the Generator Unit is hot.  At and below the Hot Cooling Boundary and up until the Warm Cooling Boundary, the Generator Unit is warm.  At and below the Warm Cooling Boundary, the Generator Unit is cold.


    Warning Limit

    means a Participant’s Required Credit Cover as a percentage of its Posted Credit Cover which it has specified to the Market Operator.  The default value of the Warning Limit is set out in paragraph 6.181


    Warning Notice

    means a Notice sent by the Market Operator in accordance with paragraph 6.181.



    means a period of seven consecutive days.


    Week Day


    every week day (Monday to Friday inclusive), including bank holidays, from the start of the wholesale Single Electricity Market.  Note that for maintenance of IT systems, the Meter Data Providers may be informed by the Market Operator that certain bank holidays are not Week Days as set out in the Settlement Calendar.



    Weekly Peak Demand Forecast

    means as defined in Appendix M: “Description of the Function for the Determination of Capacity Payments”.


    Wind Power Unit

    means a Generator Unit generating electricity from wind energy.


    Wind Power Unit Forecast

    means a forecast of the Output that will be produced by Wind Power Units, excluding Autonomous Generator Units, for each Trading Period in the following two Trading Days, as carried out in relation to each such Wind Power Unit by the relevant System Operator.


    Wind Power Unit Forecast Data Transaction

    is a Data Transaction in relation to Wind Power Unit Forecasts detailed in Appendix K: “Market Data Transactions”.


    Working Day or WD

    means a weekday which is not a public holiday or bank holiday in Ireland or Northern Ireland.  The term “Non-Working Day” shall be construed accordingly.


SEMO is a joint venture between EirGrid PLC and SONI Limited