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Developing your connection

On this page you will find out about compliance obligations before you connect and how to modify your connection application.

Modifying an application

In some situations, generators may need to modify an application. In that case, customers will need to:

To understand the costs associated with modifying an application, please refer to the Application Fee Calculator document. This tool calculates the cost of an application fee based on the location of the connection, size of connection and offer type. You can find more information about the application fee in the Use of System Charges document.

If you would like to discuss the modification application or the technical data required, please contact your Customer Contract Manager or a member of the Electricity Connections Team.

If you are looking at postponing your connection, you may be subject to charges. For projects in England and Wales, the charge is calculated on a pro-rata basis and will be payable in monthly installments from the original date of connection to 31 March in the financial year prior to that in which TEC is applicable. This can be calculated using the Investment Ahead of TEC Calculator.  This is not option is not available in Scotland.


Connection compliance

If you are a generator who is connecting to the NETS, you will have certain Grid Code compliance obligations to satisfy prior to becoming operational.

Please consult the compliance process guidance, which includes maintaining compliance during the agreement lifetime, in the Compliance Processes (CP) section of the Grid Code. The CP provides illustrative process diagrams in Appendix 1, which offer a useful overview of the process to be followed.

Operational notifications

By following the CP, new connections to the NETS will receive a 'compliance certificate', without which a new connection is unable to connect or use the NETS. This certificate is known as an operational notification.

Four types of operational notifications are defined in the Grid Code for various milestones during the lifetime of a connection.

  • Energisation Operational Notification (EON), required for first energisation of a new connection.

  • Interim Operational Notification (ION), required for first export to the NETS for a new generator connection; for offshore connections, the ION is divided into two parts dealing with offshore transmission system assets and generator assets:

    • ION Part A, required to connect dynamically controlled assets, for the purposes of active control of voltage and reactive power and not for the purpose of exporting active power; and

    • ION Part B, required to connect generator assets for the purposes of exporting active power.

  • Final Operational Notification (FON), issued when all compliance issues have been resolved.

  • Limited Operational Notification (LON), issued to a site that once held a FON but currently has a compliance issue to resolve whether from a modification or a fault.

If you have an existing agreement and wish to enquire about the compliance processes in the Grid Code please contact the Compliance and Notifications Team.

To find out more about the notifications process, please read the Introduction to Operational Notifications Process guide.

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Charges that users of the electricity transmission system have to pay, how they are calculated and what changes are currently being considered by the industry.

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After you have connected

How to modify a connection, how to disconnect, and details of the compensation process for loss of access.

Find out more