Connection configurations

When connecting to the electricity transmission network, the connection arrangement offered will depend on several factors, including your location, connection requirements, available network capacity, and the most efficient way to connect customers in a particular area.

As part of Phase 2 of Connections Reform, National Grid Electricity Transmission is moving towards shared connection solutions, referred to as ‘bay sharing’, that make more efficient use of transmission infrastructure while supporting future network growth. These solutions help maximise the use of existing assets, reduce the need for dedicated infrastructure, and create opportunities for multiple customers requiring up to 450 MW of capacity to connect through shared facilities.
 

Connection solutions currently offered

Grid Parks

A Grid Park is a shared connection solution that enables multiple customers to connect through a single transmission connection point.

Typically used for smaller generation, a Grid Park uses a shared transformer and lower-voltage infrastructure to connect up to three customers through a common arrangement. Grid Parks are an established product already used across the transmission network and provide a cost-effective and efficient way to connect smaller customers. 

Suitable for:

• Smaller transmission-connected customers
• Customers with requirements up to approximately 57 MW
• Areas where multiple customers can benefit from shared infrastructure

Find out more about some of our customers connecting into to grid parks here.
 

Super Grid Parks

A Super Grid Park is a higher-capacity evolution of the Grid Park concept, designed to connect larger customers or a greater number of customers through a shared connection arrangement.

These connections use higher-voltage infrastructure and are particularly suited to new substations where future network growth can be planned and accommodated. Super Grid Parks allow multiple customers to share infrastructure while maintaining flexibility for future expansion. 

Suitable for:

• Larger transmission-connected customers connecting projects around 150 MW
• Locations where future customer growth is anticipated
• Shared connections requiring higher overall capacity

Banking Compounds 

A Banking Compound enables multiple customers to connect through a shared high-voltage connection arrangement rather than each customer requiring a dedicated transmission bay.

This approach allows customers to retain a high-voltage connection while making more efficient use of transmission network infrastructure. By sharing a single transmission bay, multiple projects can connect in areas where dedicated bays may not be available or would not make efficient use of the network. These connections are suitable for customers connecting projects up to 450 MW.

Benefits include:

• Improved use of available transmission infrastructure
• Increased opportunity for customers to connect to the network
• Efficient use of existing substation assets
• Support for future connection growth in a particular area

Shared connection arrangements can help improve network utilisation and create additional opportunities for customers to connect to the transmission network. However, customers should be aware that these arrangements may have different operational characteristics compared with a dedicated connection, and these will be discussed as part of the connection design and offer process. 
 

Legacy connection configurations

The following connection configurations may remain relevant for existing customers. They are generally no longer offered for new connection applications as part of our current connection approach. 
 

Single HV Busbar Connections

Historically, some customers connected directly to a dedicated high-voltage (HV) transmission bay through a single HV busbar arrangement.

While these connections remain in operation for existing customers, they are no longer the standard connection solution for new smaller customers (requiring up to 450 MW) because a dedicated bay can reserve significantly more transmission capacity than many projects require. 
 

Tertiary Connections

Tertiary connections provided a bespoke connection arrangement for individual customers using dedicated infrastructure. A connection is made via a third winding, known as the tertiary winding, of a Super Grid Transformer (SGT) rather than through a dedicated transmission bay.

Although a number of customers remain connected through tertiary arrangements, they are no longer offered for new connection applications due to their complexity and comparatively high cost when measured against newer shared connection solutions. 
 

Minimum Site Interventions (Tee-Off Connections)

Minimum site intervention arrangements, often known as tee-off connections, provided a smaller-scale connection solution by connecting directly to an overhead transmission line rather than into a substation bay. 

These arrangements remain part of the network for some existing customers but are no longer generally offered for new applications. Today's connection solutions are designed to support more efficient longer-term network development and future customer growth.

If you are considering a new transmission connection, find out more on the connections process and the steps you must take to get connected.