Leading coordination for enhanced reliability of supply

Collaboration with the Great Britain Synchronous Area


In addition to performing studies for Continental Europe, Coreso is also involved in operational activities with National Grid.

Alongside coordination between TSOs in the Continental Synchronous Area, collaboration with the Great Britain Synchronous Area is becoming a reality within Coreso for several reasons:

  • The interconnected capacity between Great Britain and the Continent will more than double within the next five years, from the current 3 GW to more than 7 GW in 2020.
  • The TSOs on both sides of the Channel are participating in the Channel Capacity Calculation project.
  • The integration of renewable energy and the redesign of the generation profile in GB are causing unexpected energy exchanges with the Continent.
  • ENTSO-E’s five key tasks for RSCIs will increase the need for further coordination between the two synchronous areas.
  • Collaboration with the Irish Synchronous Area will soon become a reality.


The Day-Ahead stage

In March 2015, Coreso started a daily process with National Grid focused on data analysis and testing, by merging and publishing the first European merged file with two independent synchronous areas, using the future-proof CIM-xml format.

In October 2015, Coreso successfully started the Day-Ahead planning process with National Grid, establishing the first daily operational process between the two entities. It is also the first operational process to use the CIM-xml format for offline planning data and the first operational process with another synchronous area (GB). National Grid became the first TSO to share CIM-xml files for operational purposes. For the first few months the process will be performed as a parallel run, with the multiple objectives of increasing the coordination and knowledge sharing between National Grid and Coreso and preparing for future operational processes.

The files shared by National Grid contain a reduction of the GB network, limited to the South-East of Great Britain, and Coreso has defined an Interest Area associated with the network where the HVDC links have the highest impact. Coreso staff have been trained in the National Grid network and operational rules in order to implement this process.

In this process, NGET shares daily offline planning data corresponding to two timestamps which they prepare for their Day-Ahead studies. The data is shared in the form of two CIM-xml files which are subsequently analysed by Coreso operators. After checking the quality of the files, the operator performs a security analysis and calculates constraint limits for the network based on a set of rules for implementing remedial actions, depending on the geographical area and magnitude of the constraints. This way of analysing the GB network is inherent to National Grid’s know-how and way of operating the system. The results of this testing stage are very encouraging and will help to further improve offline planning data and interaction between the two entities.

Also at the Day-Ahead stage, Coreso engineers notify National Grid of the generation margins in the Continental area and enquire about the situation for the following day in the UK to gather any important information (low margins, unplanned outages on IFA interconnectors) in order to analyse the consequences for the mainland system.

This process requires the implementation of the necessary IT architecture as well as creating procedures and training CORESO staff. These are key to launching more processes between National Grid and CORESO.



Finally, based on each baseline situation corresponding to a merged DACF file, Coreso is also able to use IFA interconnectors to propose coordinated solutions between National Grid and mainland TSOs, thus solving congestion on both sides of the English Channel.

Coreso and NG are currently working with RTE, Elia, TenneT NL, NGIC and BritNed to develop an HVDC loopflow redirection process. Redirecting flows over interconnectors (RFIs) is an operational tool based on the ability to adjust transfers on HVDC links (IFA and BritNed) following gate closure without affecting any previous commercial or market arrangements. It involves modifying the set points of both IFA and BritNed interconnectors by the same amount and in opposite directions so that the energy balance for each TSO is unchanged but the internal flows are altered for the benefit of one or more Parties.

It will potentially provide a number of operational advantages, including ways to recover and maintain AC system security under strained conditions, manage imbalance costs for the HVDC link owners in the event of an interconnector failure and help to cut system operation costs for TSOs following gate closure. This may serve as an alternative to real-time countertrading, which very often turns out to be extremely expensive and even impossible in some situations.