Two National Grid workers

How much will it cost to maintain my connection?

Once you are connected to and using the transmission system, you are required to pay ongoing usage charges. These charges are billed monthly for the duration of your connection. There are two types of charges:

Transmission Network Use of System (TNUoS) charge

This charge covers the cost of building and maintaining the national electricity transmission network, which all our customers benefit from using. The charge differs depending on how you use the system and where your connection is located. The ESO publishes TNUoS tariffs annually, and also provides a rolling five-year forecast to help your plan for paying this charge.

TNUoS tariffs


Balancing Services Use of System (BSUoS) charge

This charge covers the ESO’s day-to-day costs of keeping generation and supply in balance on a minute-by-minute basis.  The ESO provides a monthly estimate of BSUoS tariffs as part of the monthly balancing services summary report. 

BSUoS tariffs