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EUPHEMIA is the day ahead pricing algorithm currently in use throughout Europe. It was developed by the Price Coupling of Regions (PCR) initiative, an organisation of European power exchanges. Further details on the EUPHEMIA algorithm are available here.

What is the I-SEM Trialling of EUPHEMIA?

The use of EUPHEMIA for the day-ahead market in the Integrated Single Electricity Market (I-SEM) is outlined in the SEM Regulatory Authorities’ (RAs) high level design (HLD) for the I-SEM. As such, the ability of I-SEM participants to successfully represent their trading requirements through EUPHEMIA will be explored to ensure adequate understanding of the algorithm and how it can be used in the I-SEM to allow for efficient participation in the market.

SEMO, in its role as the market operator for the SEM, member of EUROPEX and associate member of PCR, has been asked by the SEM RAs to progress this trialling.

Objectives of the Trials

EUPHEMIA allows for the use of a number of different bid and offer, collectively order, types. Each of these order types has distinct characteristics in their representation of participants’ commercial and technical data. The objective of the I-SEM trialling of EUPHEMIA is to explore the use of these order types to create SEM representative market orders and to analyse the resultant outputs. This will assist in developing participants’ and SEMO’s understanding of the EUPHEMIA algorithm.

Process of the Trials

In March 2015, SEMO published a high level plan of the I-SEM EUPHEMIA trials. This plan set out that the trials would be split into two categories, as follows:

  • Initial Phase – internal to SEMO only; and,
  • Commercial Phase – performed by SEMO in conjunction with industry.

The Initial Phase report outlines the assumptions, methods and findings of the Initial Phase. The report is available here.


Industry Working Group

In April 2015, SEMO initiated the EUPHEMIA Working Group, with the remit of providing co-operative interaction between Industry, Regulatory Authorities and SEMO with a view to developing scenarios to be used in the trialling work. In line with the overall objectives in the EUPHEMIA trial, the Working Group has achieved the following:

  • Provide a platform for discussion of trials between SEMO and industry representatives
  • Allow for industry to provide input into planning activities, e.g. formation of trial scripts
  • Allow for industry to provide input into analysis of trial results
  • Provide a regular forum for updates on the status and progress of trials by SEMO

Throughout this process SEMO has facilitated monthly meetings with the Working Group, at which, SEMO has presented updates, plans for trial events, analysis of results and developments regarding EUPHEMIA. Terms of reference, working group members and Initial Phase data can be viewed using the links below.   A summary of each of these monthly updates and links to the presentations given at each Working Group may also be viewed using the links below.
The terms of reference for the working group may be viewed here.
The industry working group members list may be viewed here.
Information on the preparation of Initial Phase data may be viewed here.

Working Group Meeting 1 16/04/2015

  •  Background of EUPHEMIA algorithm
  •  Overview of background and goal of EUPHEMIA trials
  •  Overview of Initial Phase goals and criteria
  •  Presentation of the assumptions used
  •  Presentation of early Initial Phase results
  •  Discussion of areas for further study
  •  Discussion of next steps


Working Group Meeting 2 21/05/2015

  • Review of Trial Batch 2 Results
  • Demonstration of EUPHEMIA Data Template
  • Discussion of Trial Assumptions
  • Discussion of Trial Scenarios


Working Group Meeting 3 23/06/2015

  • Trial Batch 3 Script and Assumptions
  • Further Analysis of Trial Batch 1 and 2
  • Discussion of Confidentiality
  • Scenarios Feedback for commercial phase
  • Proposed Plan for Commercial Phase


Working Group Meeting 4 23/07/2015

  • Further Analysis of Trial Batch 1 and 2
  • Trial Batch 3 Preparations
  • Initial Phase Report
  • Review for Commercial Phase Plan


Working Group Meeting 5 07/09/2015

  • Review of working group feedback
  • Review of commercial phase plan
  • Review of trial script
  • Technical expert from PCR Algorithm Working Group


Working Group Meeting 6 12/10/2015

  • Review of commercial phase plan
  • Algorithm expert feedback
  • Review of trial script and assumptions


Working Group Meeting 7 12/11/2015

  • Recap of OMIE Discussion
  • Review of commercial phase batch 1 analysis
  • Discussion of recent working group feedback on results
  • Discussion of commercial phase batch two plans
  • Proposals for training arrangements


Working Group Meeting 8 07/12/2015

  • Review of commercial phase batch 2 analysis
  • Discussion of commercial phase batch 3 plans
  • Discussion of recent working group feedback for batch two
  • Arrangements for unscripted phase training


Working Group Meeting 9 26/01/2016

  • PCR/EUPHEMIA Update – covering recent meeting of stakeholders with algorithm developers in Brussels
  • Recent WG Feedback on results and plans for next batch
  • Batch Two Results and Analysis
  • Batch Three Trial Script


Working Group Meeting 10 10/03/2016 

  • Paradoxically Rejected Blocks
  • Batch 3 results and analysis
  • Batch 4 trial script
  • Unscripted phase arrangements
  • Report arrangements



Working Group Meeting 11 12/04/2016

  • Batch 4 results and analysis
  • Unscripted phase one input breakdown
  • Trial Report


Working Group Meeting 12 18/05/2016

  • Unscripted phase 1 inputs and results
  • Unscripted phase 2 results
  • Trial report
  • Arrangements for input to report


The Commercial Phase Report was published on 31/05/2016 and can be viewed below.


SEMO recieved 2 responses from the working group Commercial Phase Report which can be viewed using the links below.

Energia Response

Power NI Response

Any queries in relation to the I-SEM trialling of EUPHEMIA should be directed to

SEMO is a joint venture between EirGrid PLC and SONI Limited