EirGrid and SONI have a number of reporting and monitoring obligations under EU Regulations. The goal is to increase integrity and transparency of wholesale energy markets. This fosters open and fair competition in wholesale energy markets, benefitting final consumers of energy.

TSO and transparency

In order to provide transparency for the scheduling and dispatch process we publish documents that describe the process, its inputs (such as demand and wind forecasts) and its outputs (indicative operations schedules and dispatch instructions). We support the provision of information to Participants and the wider industry. This information is key to a well-functioning market and to assist understanding of our decision making processes.

Operational Data

Operational data consists of the inputs to, and outputs from, the scheduling and dispatch process. These consist of large volumes of automatically generated reports which are provided on a regular basis. 

EirGrid and SONI produce demand forecasts representing the predicted electricity production required to meet demand including system losses. This is net of unit demand requirements (‘houseload’). We publish a daily 4 day demand forecast at half hour resolution. We update this forecast on a continuous basis to account for actual demand conditions and interpolate the forecast to a 1 minute resolution for use in the scheduling and dispatch process. 

This report contains the load forecast per jurisdiction (ROI & NI), an aggregated value for both Jurisdictions and assumptions, for each Trading Period in the following calendar month.

This report contains the load forecast per jurisdiction (ROI & NI), an aggregated value for both Jurisdictions and assumptions, for each Trading Period in the following calendar month.

This report contains the load forecast per jurisdiction (ROI & NI) and an aggregated value for both Jurisdictions, for each Trading Period in the relevant year.

We procure wind power forecasts from two forecast providers. These forecasts include the forecast power output from each wind farm greater than or equal to 5 MW along with the total aggregate forecast power production and an uncertainty of the aggregate power forecast. Standing data, such as location, turbine number, type and model and hub height, for each wind farm is provided to the wind forecast providers.

In addition, meteorological measurements and SCADA from each site (where available) are sent to the providers on an ongoing basis. This information is used by the wind forecast providers to develop and train models for each wind farm. Wind forecasts do not include curtailment forecast as these are only implemented in real-time operation. The forecast providers are supplied with wind farm outages information where these are available.

  • BM - 012: Four day rolling wind unit forecast report (not available)

This report is produced four times per day and contains the expected output (MW) for each Wind Unit per 15 mins in the next four Trading Days, produced following the receipt of each accepted Wind Power Unit Forecast.

This report is run four times per day, containing the aggregated output (MW) across all Wind Units in each jurisdiction, for the next four Trading Days, produced following the receipt of each Wind Unit Forecast.

All –Island Monthly Wind Forecast Accuracy Report for Primary and Secondary Wind Forecast Vendor

The impact of solar generation is becoming increasingly significant on the operation of the power system so we are currently developing our forecasting capability in this area. We will provide updates on this development as appropriate.

Scheduling is the process of planning the dispatch instructions that issue based on specific inputs. Our scheduling process operates from close to real-time through to the next Trading Day. Given the volume of inputs to the process and the complex nature of the process itself, it is split into a number of timeframes that allow for short term analysis to be performed quickly and regularly while longer term analysis, which takes more time to process, is performed less frequently.

The aim is to achieve a rolling, integrated and current plan of ‘unit commitment’ and ‘economic dispatch’ actions. Long Term Schedule produces unit commitment advice from four hours ahead to up to 30 hours ahead.

Long Term Schedule Operational Schedule for Generator Units and Demand Side Units registered in the market.

This report contains the Dispatch Instructions for the previous Calendar Day, for all applicable Units.

This report contains Dispatch Instructions for all applicable Units for Calendar D-4.

Generation Outages

EIrGrid and SONI develop and implement a Generation Outage Plan. This ensures co-ordination of 'planned outages' when generation stations will not be available due to maintenance or other reasons. The Generation Plan takes into account security of supply in Ireland and Northern Ireland as well as economic operation of the power systems and the maintenance/resource needs of generators.

REMIT Outages

EirGrid is currently sending out updates (via email) to Regulation on Wholesale Energy Markets Integrity and Transparency (REMIT) publication. This is in the event that there is a significant change to the outage schedule. If market participants wish to be included in an email distribution list, please subscribe to the relevant section on the subscribe option in the footer. Note that these emails will only be sent during normal office hours.

Under REMIT, market participants are obliged to fulfil obligations specifically that: "Market participants shall publicly disclose in an effective and timely manner inside information which they possess".

EirGrid and SONI currently publish detailed generator and interconnector unit outage plan updates in a regular and timely manner. This improves transparency and assists market participants in complying with REMIT. Thus, in addition to the two monthly All-Island Generation Outage Plan a weekly All-Island Outage Plan is published under REMIT Reporting on the EirGrid website.

Weekly report manually uploaded.

Transmission Outages

EirGrid develops a Transmission Outage Programme and manages transmission outages. This involves planned times when transmission infrastructure will be out of service for maintenance. It also involves times when testing, connection of new plant and decommissioning of old plant is carried out. Transmission maintenance takes place in line with EirGrid Asset Maintenance Policy to ensure that the transmission system can operate in a safe, secure and reliable manner. 

Programme for the remainder of the year of scheduled times when transmission infrastructure (line, cables and substations etc) will be out of service for maintenance. It also involves times when testing, connection of new plant and decommissioning of old plant is carried out.

Document communicating the Transmission Outage Summary for the next fortinight

Report containing the transmission outages scheduled for the next trading day.

Constraints impose limits on the physical operation of units in order to maintain operational security requirements under normal and contingency (failure of an item of equipment, e.g. transmission line or unit) conditions. We determine constraints through planning studies, real-time analysis and monitoring of the power system.

The majority of constraints are known in advance and are modelled in the scheduling tools to ensure that the resulting schedule respects known requirements. Other constraints may arise through real-time analysis and monitoring and are managed in real-time operation.


The following reports provide Participants with information on the outcome of the scheduling and dispatch process.

Sets out in a clear and comprehensible manner how EirGrid and SONI fulfill the statutory obligations that govern our scheduling and dispatch process under revised SEM arrangements.

Includes the independent Auditor's opinion on the compliance of specified elements of the scheduling and dispatch process for the 2018 to 2019 audit period. A supplement within the document describes the approach to the assurance engagement and descriptions of the tests undertaken.

This Report contains the Quarterly Renewable Dispatch Down (Constraint & Curtailment) data.

These Reports contain Annual Renewable Dispatch Down (Constraint & Curtailment) data.

This report contains the quarterly constraint cost outturn.

This report contains high level transmission system characteristics and a detailed breakdown of key figures along with an explanation of what these figures mean for the all-island transmission system in the coming year and into the future.​​

Operational Methodologies

We publish a number of methodologies related to the scheduling and dispatch process.

These two methodology documents expand on the information in the Balancing Market Principles Statement.

Under EirGrid and SONI Licences we are required to apply policy parameters in our scheduling and dispatch process to give effect to RA policy. These parameters are designed to reduce the propensity for starting-up long-notice units over shorter notice units in our scheduling process. Along with other aspects of the scheduling and dispatch processes, this outcome is designed to contribute towards the objective of enabling ex-ante markets to resolve energy imbalances.

In certain instances the implementation of specific obligations is bound by the practicalities of the scheduling and dispatch process such as the necessity to produce and update schedules in a timely manner. The distinction between energy and non-energy actions is not made in the scheduling and dispatch process for example.The distinction is made in the ex-post imbalance pricing process as described in this methodology for System Operator and Non-Marginal Flagging document. ​

This document sets out the interim arrangements across the Ireland UK (IU) region for the TSOs to determine the interconnector capacities available to be allocated by the day-ahead and intra-day market coupling process.

Market Operator Special Topic