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 Market Development 

Market Rules

The Trading and Settlement Code (the Code), including its Appendices, Agreed Procedures and any effective Modifications (not already incorporated into the main text of the Code) provides the rules by which the Market and its Participants may operate. The Code aims to facilitate the achievement and efficiency, development, financial security, participation, competition, transparency and equity within the Market.

The Code is published on a bi-annual basis in line with the Scheduled Release of the Central Market Systems, in April and October. This is due to a number of Modifications requiring both Code and Systems changes in order to become effective. However, should a number of non-System Modifications be approved, an interim version of the Code may be published.


In accordance with the provisions of the Trading and Settlement Code, the Modifications Committee exists to progress Modification Proposals with a view to better facilitating the achievement of the Code Objectives of efficiency, development, financial security, participation, competition, transparency and equity within the Market.

The Modifications Committee meets every two months in either Dublin or Belfast. The Committee is charged with the assessment of proposals submitted to them and making decisions on directions for development of the Market. The Committee has the ability to convene Working Groups or undertake public consultations to ensure appropriate consideration and impact assessment is undertaken prior to making any key decisions.

The Modifications Committee Secretariat sits within SEMO and is responsible for the coordination and publication of information on meetings, Working Groups, consultations and other activities undertaken by the Committee. The Secretariat may be contacted via

The rules governing the Modifications Committee are contained within Section 2 of the Trading and Settlement Code and Agreed Procedure 12.


Building a market model involves re-creating a representation of the market in a mathematical modelling software package. A model makes assumptions about key components of the system and how they will change over time – demand, fuel prices, generation resources, market rules and interaction with other systems.

 Modelling simulates the operation of the market and provides forecasts on areas of study such as plant scheduling, CO2 emissions, production costs and market price.

Regulatory Affairs

The Regulatory Affairs Group within Market Development liaises with many different stakeholders on various regulatory issues that may impact them. Regulatory Affairs:

 ·        Delivers the Market Systems Development Plan

·        Consults with market participants on issues which impact them (e.g. SDS)

·        Co-ordinates the SEMO Price Control submissions and

·        Manages the Compliance obligations within the:

             o       Two Market Operator Licenses (EirGrid and SONI) and

             o       The Trading and Settlement Code.

 Market Analysis

The Market Analysis section of Market Development work on the development of the Market Rules to further the objectives of the Trading and Settlement Code. They represent SEMO on the Modifications Committee as MO Member and Alternate. Since the inception of SEM they have proposed and developed numerous modifications to the Trading and Settlement Code, working with Market Participants, the System Operators and the Regulatory Authorities to enhance the operation of the market. Their work includes the analysis of policy decisions and their impact on the Market Rules, on the operation of the market for which they liaise with SEMO Market Operations and on the Central Market System where they liaise with SEMO IT.

The section also monitors developments in other electricity markets and co-ordinates responses to energy policy consultations.


SEMO is a joint venture between EirGrid PLC and SONI Limited