We are becoming a separate company

In April 2019, Electricity Transmission is becoming a separate company within the National Grid Group. Find out more about what this change will mean.

Network capacity map

The purpose of this tool is to help you to assess the availability of capacity on the transmission network in England and Wales. It gives a general indication of the capacity available for generation/demand developments looking to connect to the transmission system at major England and Wales substations. 

The colour gradings are intended to provide an indication to the user of constraints on the England and Wales transmission network and the areas where a connection is more likely to be achieved without the need for significant transmission reinforcement(s). 

The main points to note regarding the network capacity map are:  

  • the data is provided as an indication only and further system studies will need to be carried out in respect of the specific proposed connection during the connection application. This is to ensure we provide a more accurate measure of the impact on the transmission network in England and Wales 

  • the data within the map is updated every six months (to reflect changes on the England and Wales transmission network) but please note that the transmission system is always subject to changes 

  • the “generation headroom” and “fault level headroom” values given for the major England and Wales substations are calculated by taking into account connected generation, generation which has accepted an offer for connection but which has not yet connected and calculated capacity of the substation. These generation figures will regularly change as offers are issued, accepted or lapse 

  • the “demand headroom” values given for the major England and Wales substations are calculated by taking into account current peak demand values and calculated capacity of the substation 

  • currently the network capacity map cannot differentiate between multiple offers for the same transmission substation site inflating the overall connected generation figure and in the event this occurs the Interactivity Process outlined within the (Customer Use of System Code) CUSC will be followed. 

Please note that connections to the transmission substations with an overall RED classification are still possible, but there is likely to be a requirement for significant transmission network reinforcement.  

The network capacity map does not replace a full formal application when determining network capacity and to obtain a more accurate indication of the capacity available and any transmission works please submit an enquiry using the Enquiry Form.  


The cost estimator and network capacity map give a general illustration of capacity and costs to apply to connect to the transmission network in England and wales. 

The network capacity map identifies where constraints exist. It is intended to give an indicative view and should not be relied upon to assess the network capacity or terms of a specific connection. While 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.  

We have included maps showing the approximate boundaries of land owned by National Grid Electricity Transmission plc (“National Grid”) which may be of interest to you in the context of potential connections. Please note that the land may be subject to third-party interests or tenancy agreements. If the land is of interest to you and you would like to understand more about a specific plot, then please use the enquiry form on the Electricity Connections website.

Please note that in considering any enquiries National Grid is not making any commitment regarding the availability of the land or any associated connection which will be considered independently of each other or as a combined land & connection enquiry. Initial enquiries are limited to a maximum of 10 plots unless otherwise agreed with National Grid.

National Grid reserve the right to terminate the land option if contractual milestones and conditions are not met. Both National Grid and the customer can agree not to progress a Heads of Terms, if options are not progressed within 4 months.

This map does not currently include all the land owned by National Grid. It is our intention to include additional holdings over time and in the interim period we welcome enquiries around sites not listed.

Legal disclaimer: we have developed the guides to prices and timescales to assist you with connections applications. They give a general illustration of connections cost and time to connect only and cannot be relied upon to assess the terms of connections for specific premises. 

Subject to the above, we shall not be liable to you in tort (including negligence) or otherwise, arising under or in connection with your use of the  cost estimator or network capacity map for: (a) loss of profits; (b) loss of sales or business; (c) loss of agreements or contracts; (d) loss of anticipated savings; (e) loss of or damage to goodwill; or (f) any indirect or consequential loss. 

Please accept the terms and conditions.

Low — less than 10% total site capacity still available
Medium — 10% to 25% total site capacity still available
High — 25% total site capacity still available
ID Name Demand Headroom Generation Headroom Fault Level Headroom Lease Availability

Do you need some guidance to use the capacity network Map and get your data?

What are you planning to connect?

What type of connection?

What capacity are you connecting? (MVA)

Do you have an idea of where you want your connection?

Do you have an idea where do you want your connection?


Substation Name:

Substation Type:

Voltage Level:

Substation Technology:


Spare Bays:

Spare Tertiaries:

Demand Information

Demand Capacity: MW

Peak Demand: MW

Demand Headroom: MW

Demand Potential:

Generation Information

Generation Capacity: MW

Connected Generation: MW

Contracted Generation: MW

Generation Headroom: MW

Generation Potential:

Fault Level Information

Fault Level 3Ph Rating: kA

Fault Level 3Ph Fault Level: kA

Fault Level 1Ph Rating: kA

Fault Level 1Ph Fault Level: kA

Fault Level Headroom: kA

Fault Level Limitation:

National Grid Land Boundary

Lease National Grid Land

There are opportunities to lease National Grid land at this site. Ask for further details through our enquiry form.


Lease National Grid Land

There are opportunities to lease National Grid land at this site. Download our Land Pack for further details.

Download Land Pack

Connection Information

TNUoS Zone:

TNUoS Charge: £ / MW

Point of Connection Cost: £k

Average Reinforcement Cost:

Indicative Timescale:

Technology Availability: