This network capacity map to gives you an indication of the available transformer capacity at primary substations. The map only indicates transformer capacity and does not guarantee the same capacity is available in the upstream networks.  It cannot be relied upon to assess the terms of connection for specific premises. Whilst we use reasonable endeavours to ensure that the network capacity map and related information is accurate, we do not warrant, and do not accept any responsibility or liability for, the accuracy or completeness of the content or for any loss which may arise from reliance on the network capacity map or related information. The legal disclaimer  terms and conditions for use of our website apply to the network capacity map and related information.

Note regarding the demand map data

  1. The map is an indicative list of the transformer capacity available at each distribution primary substation provided by transformer group*. The map is intended to guide industrial/large commercial scale users to primary substations where a connection is more likely to be achieved without significant reinforcement.


  2. Station locations are only indicative.


  3. The data has been produced by a basic analysis of the available transformer capacity, existing loads and contractual commitments to new customers. Detailed assessment aspects such as load transferability has not been included.


  4. In some cases, the available capacity shown may already be contracted to individual customers but is not currently being fully utilised.


  6. The available demand capacity figures are based on:

    Peak winter network demands for 2018/2019

    Installed transformer capacity for December 2018.

    Customer demand contracts and offers as of end of January 2020.


  7. It does not guarantee the same capacity is available in the upstream DSO networks.


  8. Any increased load on the Distribution System will impact on the upstream Transmission System and reinforcements may be required on the Transmission System in order to cater for these loads. This will be separately assessed by the TSO.


  9. For each Primary Substation the lower voltage side of all transformer groups have been given an overall classification (Red/Amber/Green) based on the known calculated available capacity. The station marker will have the same colour if all transformer groups have the same classification. If there are mixed transformer group classifications the station colour marker will be BLUE.


    Marker Colour


    Mixed result for different transformer groups within the substation. See the substation detailed text for individual results.


    Greater than 5MVA available


    Greater than zero and less than 5MVA


    No capacity available


  10. The map does not replace a full formal application in determining network capacity.


  11. Connections to the substations/transformers with an overall RED classification are still possible, however there might be a requirement for significant network reinforcement to overcome the impact on the network constraints.


  12. The map does not provide capacity figures for the final connection from HV substation to customer premises. Such connections will need to tap into the existing MV (10kV or 20kV) network and capacity availability are subject to many variables and bespoke assessment is necessary.

    However, in general, where HV substation capacity is adequate, MV connections up to a maximum of 10MVA will entail construction of overhead line or new underground cable network, associated civil works and minor station works only and typically do not require planning permission. These would not be expected to take longer than 6-9 months; however, any instances requiring significant station work such as the installation of a new transformer or MV switchgear will require increased time, and possibly planning permission and would typically be expected to take approximately 2-3 years.


  13. (*) Transformer groups are defined as the transformers which have the same lower voltage and are couplable on both sides.Transformers that are ordinarily coupled are shown with a “parallel” symbol in the group label e.g. T41‖T42. Transformers that are not normally coupled are shown with an ampersand (&) in the group label e.g. T41 & T42. Individual non-couplable transformers are shown as separate groups.


  14. Any single connection cannot be greater than the capacity of an individual transformer capacity whether or not a transformer is part of a group. Furthermore, any individual connection will typically be constrained to a maximum of 50% of transformer capacity so that reserve is available for other customers in the event of a contingency.Constraint may be deeper for demand connections from single transformers as contingency cover will need to be provided from another source via downstream network.The capacity that can be made available to an individual connection is also impacted by network connection method and downstream network. The capacity can only be determined through a detailed study taking into account downstream network topology and its ability to transfer load under contingency.



  15. To make a demand application for capacity please complete the NC3 form available on the ESB Networks website: https://www.esbnetworks.ie/


  16. If you would like to make a comment or seek clarification, please contact us on: innovationfeedback@esbnetworks.ie