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 I-SEM Market Rules FAQ 

 1. How many days a week will the I-SEM Day-Ahead Market run?

2. How are "Working Days" and relevant "Non-Working Days" defined when settling on the Balancing, Capacity Market, Day-Ahead and Intra-Day Markets?

3.For the payments of invoices, do we have to take into account both ROI and Northern Ireland bank holidays regardless of the entity (NI or ROI participant), place of transactions ( local or cross border)?

1. How many days a week will the I-SEM Day-Ahead Market run?

As outlined in the SEMOpx Market Design Document, the auctions and continuous market of SEMOpx are run each and every day (including weekends and bank holidays). Bids can be entered anytime between the order book opening (gate opening) and the order book closing (gate closure).

In the case of the Auctions:
- Each auction opens 19 days before the delivery date (i.e. the date on which the energy is delivered to the system) so this would allow for early entry to take account of weekends and bank holidays.

In the case of the Continuous Market:
- The nature of this kind of market does not owe itself to early opening (i.e. as opposed to an auction which gathers all orders until the order book closes and solves for all orders simultaneously, a continuous market continuously matches orders in real-time).
- As such, the Continuous Market will open each day for the following day.

Please note that each market segment (DAM/IDM/Continuous) is voluntary so a participant would not be obliged to take part in any or all. Whether a participant decides to take part, and when they wish to submit bids is up to their own operational decisions (allowing for the gate opening and closing times described above).

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2. How are "Working Days" and relevant "Non-Working Days" defined when settling on the Balancing, Capacity Market, Day-Ahead and Intra-Day Markets?

A weekday which is not a public holiday, bank holiday or non-processing day as advised by the SEM Bank in Ireland or Northern Ireland. The term “Non-Working Day” shall be construed accordingly.

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3. For the payments of invoices, do we have to take into account both ROI and Northern Ireland bank holidays regardless of the entity (NI or ROI participant), place of transactions ( local or cross border)?

Holidays in either jurisdiction must be considered as Non-Working Days for all Markets:  Balancing, CRM Capacity Remuneration Mechanism, Day Ahead or Intra Day.
The Market Operator will publish on a yearly basis a Settlement Calendar detailing the status of each day and highlighting the known activities that are planned to take place in each Working Day, including Payments deadline, publication of Statements etc.

This is done in accordance to the relevant timetables set out in both the Trading and Settlement Code and the Capacity Market Code.


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SEMO is a joint venture between EirGrid PLC and SONI Limited