SEMO and Guarantees of Origin

A Guarantee of Origin is an electronic document that proves to a final customer that a quantity of electricity originated from a specific renewable energy source. The Guarantee of Origin tracks renewable energy production to the final customer, providing full transparency for these consumers.

Each Guarantee of Origin

  • Represents 1 megawatt-hour of electricity produced; and
  • Contains all relevant registration information related to the production device

SEMO operates the registry for Guarantees of Origin in Ireland available at



SEMO was nominated as the Issuing Body for Guarantees of Origin in Ireland in Statutory Instrument No. 147 of 2011 and No. 483 of 2014 (which transposed EU Directive 2009/28/EC regarding the promotion of the use of energy generated from renewable sources into Irish law). The Supervisory Framework published by the Commission for the Regulation of Utilities (CRU), after consultation with SEMO and the industry, outlines the GO processes applicable in Ireland.

The EU has agreed a comprehensive update of its energy policy framework called the "Clean Energy Package for all Europeans package". Following "political agreement by the Council and the European Parliament in 2018 and early 2019, enabling all of the new rules to be in force by mid-2019, EU countries have 1-2 years to transpose the new directives into national law".


Association of Issuing Bodies

SEMO is a member of the Association of Issuing Bodies (AIB). AIB facilitates the international exchange of Guarantees of Origin via the inter-registry telecommunications hub (AIB hub). To support international trade of Guarantees of Origin, AIB developed a standardised system called the European Energy Certificate System (EECS). The SEMO Domain Protocol outlines how Guarantees of Origin procedures in Ireland align with the EECS rules.


GO scheme

Any electricity producer (not in receipt of support) or supplier active in the Irish domain can register as an Account Holder in the GO scheme.

Applicants will be asked to agree to the Standard Terms and Conditions for the scheme. When the application has been completed, the producer/supplier becomes known as an Account Holder and the Account Holder Root User is sent their credentials for login to The Root User can then process GO transactions for the Account Holder including:

  • Production Device Registration, and requesting the issue of Guarantees of Origin
  • Transferring GOs to other Account Holders in Ireland, or importing/exporting GOs from and to other European Member States
  • Cancellation of Guarantees of Origin for use in Fuel Mix Disclosure (by suppliers only)

For more information on these procedures, refer to the SEMO business processes or request a call back from the Guarantees of Origin team.

Currently ‘Trader only’ accounts are not permitted in the Guarantees of Origin scheme in Ireland.

Guarantees of Origin Timelines

SEMO in its capacity as the issuing body of Guarantees of Origin are required to issue Guarantees of Origin in accordance with an agreed upon timeline. The timeline for the coming year can be found below

Production MonthMeter data available in Online RegistryAccount Holder Submit GO Request BySEMO Issues GO's By 
  Issue Month + 11 WD Issue Month + 15 WD Last WD of the month ROI Bank Holidays
Jan 15/02/2021 19/02/2021 26/02/2021 New Year's Day (Fri 1 Jan 2021)
Feb 15/03/2021 22/03/2021 31/03/2021 St Patricks Day (Wed 17 Mar 2021)
Mar 16/04/2021 22/04/2021 30/04/2021 Easter Monday (Mon 5 April 2021)
Apr 18/05/2021 24/05/2021 31/05/2021 Early May Bank Holiday (Mon 3 May 2021)
May 16/06/2021 22/06/2021 30/06/2021 June Bank Holiday (Mon 7 Jun 2021)
June 15/07/2021 21/07/2021 30/07/2021 -
July 17/08/2021 23/08/2021 31/08/2021 August Bank Holiday (Mon 2 Aug 2021)
Aug 15/09/2021 21/09/2021 30/09/2021 -
Sep 15/10/2021 21/10/2021 29/10/2021 October Bank Holiday (Mon 25 Oct 2021)
Oct 15/11/2021 19/11/2021 30/11/2021 -
Nov 15/12/2021 21/12/2021 31/12/2021 -
Dec 17/01/2022 21/01/2021 31/01/2022 -

Account Holders

For a list of the current Account Holders in the Irish Guarantees of Origin scheme, visit and select the 'member' report for domain Ireland. A list of the Production Devices is also available by selecting the 'plant' report.