Fuel mix

Fuel mix disclosure is required under European legislation and the CRU has the role to ensure that suppliers provide reliable information on customer bills and other promotional material. It is the role of the Single Electricity Market Operator (the SEMO) to administer and calculate the fuel mix figures from the information provided by the electricity suppliers. The Fuel Mix Disclosure Information Paper is published once a year by the Commission for Regulation of Utilities (CRU).

The fuel mix of suppliers and associated environmental impact information (emissions) is calculated for the period from January to December by the SEMO in accordance with the SEM Committee’s decisions. This calculation is completed at the end of the second quarter of each year.

The CRU is required to ensure that all suppliers provide reliable information on bills and promotional materials sent to customers regarding the contribution of each energy source to the overall fuel mix of the supplier concerned and the associated environmental impacts in the preceding year.

Guarantee of Origin (GO)

A Guarantee of Origin (GO) certificate is an instrument defined in European legislation that certifies that electricity generated is from renewable energy sources.  The GO guarantees that one MWh of electricity has been produced from renewable energy sources.  Electricity suppliers buy GOs to certify that their electricity demand is covered by certified renewable sources. A GO is a "green label" which ensures that one MWh of electricity has been produced from renewable energy sources and when customer buys power which has been certified with GOs, the customer has a guarantee that the electricity is from renewable sources.

In Ireland, SEMO is a member of the Association of Issuing Bodies (AIB) since May 2015. AIB is a European body that provides a standardised system for European Energy Certificate System - "EECS" and GOs are part of this European certification system. In Ireland, SEMO is the body that issues GOs to generators.

Guarantees of Origin are electronic certificates issued for energy generated from renewable sources and are issued to renewable generators that are not in support schemes (such as the PSO in Ireland) per MWh of generation. These are tradeable instruments and do not need to follow the flow of energy. Guarantees of Origin Certificates are traded at a European level. The AIB operates a hub where such certificates can be traded between countries. Suppliers can purchase Guarantees of Origin certificates to use as proof of the share or quantity of energy from renewable sources in their Fuel Mix. Guarantees of Origin are both imported and exported between Ireland and the rest of Europe.

Renewable generators that are signed up to the Guarantees of Origin scheme are issued GOs per MWh of generation which can then be transferred to suppliers to use in their fuel mix disclosure. Each year, suppliers submit a fuel mix declaration form to the Single Electricity Market Operator (SEMO), which performs the fuel mix calculation on behalf of the Regulatory Authorities. This declaration outlines all of a supplier’s claims on electricity, broken down into Guarantees of Origin held by the supplier on SEMO’s registry, Renewable Energy Guarantees of Origin (which are held on Ofgem’s registry) and the attributes of specific generators, some of which may be supported by the Public Service Obligation levy.  A Supplier can also include non-renewable Generator Attributes in its fuel mix declaration.

Public Service Obligation (PSO)

The Public Service Obligation Levy, or PSO Levy, is collected from all electricity customers in Ireland through their energy bills. It covers various subsidy schemes designed by the Irish Government to support its national policy objectives related to renewable energy and indigenous fuels for Ireland.
The proceeds of the levy are used to contribute to the additional costs incurred by PSO-supported electricity generation which are not recovered in the electricity market, typically via contracts that suppliers have in place with electricity generators.

The CRU’s role is to calculate the PSO levy in accordance with Government policy and to help ensure that the scheme is administered appropriately and efficiently.

The Renewable Energy Feed in Tariff (REFIT) schemes/supports are funded by the Public Service Obligation (PSO) which is paid for by all electricity consumers. The REFIT schemes have been designed to incentivise the development of renewable electricity generation in order to ensure Ireland meets its goal of 40% of electricity coming from renewable sources by 2020. More information on government support mechanisms for renewable electricity can be found on the DCCAE Website.

CER/17/241 – PSO Levy 2017/18

CER/08/236 – Calculation of the R-factor in determining the Public Service Obligation Levy

CER/08/153 – Arrangements for the Public Service Obligation Levy

CER/03/013 – PSO Invoicing and Collection Procedures


For further information or queries relating the electricity Public Service Obligation Levy (PSO), please contact us at pso@cru.ie