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Supply: Frequently Asked Question 

Prerequisites to Joining the Market

Before an application to register units in the Single Electricity Market can be considered, there are pre-requisite criteria that must be fulfilled.


Contact with the following organisations will be required in order to meet the pre-requisites of registration.


Northern Ireland

Republic of Ireland

Regulatory Authorities



Metered Data Provider

Distribution Connected



Transmission Connected



Connection Agreements

Distribution Connected - DSO


ESB Networks

Transmission Connected - TSO



Use of System Charges

Distribution Connected - DUOS


ESB Networks

Transmission Connected - TUOS



Supply Units in SEM

Supplier Units are a collection of demand sites for which metered consumption is aggregated.

There are several distinct types of Supply Units for the purposes of participation:

  • Trading Site Supplier Unit
    Supplier Unit that contains only the demand within a Trading Site and is settled on a net basis against the Generator Units on that Trading Site.
  • Associated Supplier Unit
    A Supplier Unit which is recorded to a Trading Site but may also contain demand outside that Trading Site and has its demand settled on a gross basis with the Generator Unit(s) on that Trading Site.
  • Error Supplier Unit
    Each jurisdiction has an Error Supplier Unit for which loss adjusted net demand in that jurisdiction, allowing for net transfers between jurisdictions, is calculated.

How do I register a Supply Unit?

The following details the documentation and fee that is required by SEMO

Documents Required

Northern Ireland Applications

Republic of Ireland Applications

Participation Notice



Participation Fee

£2,701.98 (incl. VAT)
£2,251.65 (excl. VAT)

€3,210.30 (incl. VAT)
€2,610 (excl. VAT)

Finance Data Spreadsheet



Collateral Data Spreadsheet



Supply Unit Spreadsheet



Form of Authority and Proof of Consent

If applying as an intermediary

If applying as an intermediary

  • Participation Notice
    The Participation Notice is the application form which an applicant must complete if they wish to register a unit or units in the Single Electricity Market. The data the applicant provides will be used by the Market Operator in order to progress the Participants application.
  • Participation Fee
    The Participation Fee is charged per unit and the currency in which it is paid is decided on by the location of the actual unit. Companies who are VAT registered outside ROI & NI pay rates excl. VAT. If you have any questions before paying your Participation Fee, plese contact to confirm the approrpriate fee.
  • Financial Data
    The financial data document captures the bank details of the applicant.
  • Collateral Data
    An applicant must provide expected consumption volumes for five months. This allows the applicants credit cover requirement to be calculated.
  • Supply Unit Data Spreadsheet
    This document provides technical and general information to SEMO, such as contact details etc
  • Form of Authority and Proof of Consent
    Form of Authority and Proof of Consent will be required if there is an intermediary acting on behalf of the applicant. Proof of Consent is granted by the relevant Regulatory Authority. The Form of Authority is completed between the Intermediary and the Unit Owner.

Please post the completed Participation Notice and Participation Fee (Form of Authority and Proof of Consent also if applicable) to:

  • SEMO Customer Service
  • The Oval
  • 160 Shelbourne Road
  • Ballsbridge
  • Dublin 4

Please email the completed spreadsheets which accompany the Participation Notice to:

What happens next ?...

Once SEMO have received the participation fee and the application pack has been validated as complete you will be issued with a receipt for your application. This starts the registration process.

The various documents submitted will be circulated to all relevant parties such as the System Operator, Meter Data Provider and within SEMO:

  • The Meter Data Provider will ensure the meter feeds to SEMO are correctly configured
  • SEMO Credit Risk Management will calculate collateral credit cover requirements
  • SEMO Funds Transfer will validate bank details for new Participants
  • SEMO IT will provide details for Communication Channel Qualification Testing

Once these tasks and any clarifications required have been addressed and completed all parties will be in a position to discuss an effective date for the unit to enter the market.

This proposed effective date may require certain issues to be addressed at least five working days before the effective date. Providing all requirements have been met the unit will enter the market and a Commencement Notice will be issued to the Participant.

SEMO Customer Services will also be facilitating Participant Readiness during this process to ensure a smooth transition to becoming a Market Participant – please click here to view the services provided.

If you need any further information on joining the market or require assistance with your application please email :


SEMO is a joint venture between EirGrid PLC and SONI Limited