SONI (Electricity System Operator for Northern Ireland) and NIE Networks Transmission Interface Arrangement Consultation

03 July 2020

SONI, the Electricity Transmission System Operator for Northern Ireland, and Northern Ireland Electricity Networks (NIE Networks), the Transmission System Owner, work in partnership to serve Northern Ireland consumers, by providing a safe, reliable and efficient electricity supply. 

We operate through the Transmission Interface Arrangements (TIA) which has been in place since 2007. The TIA is designed to promote co-operation and co-ordination between SONI and NIE Networks in planning and developing the transmission system.

Working together, both companies have carried out a joint review of the Transmission Interface Arrangements, with emphasis on the pre-construction elements of grid development projects.

The findings concluded that the processes in place are operating proficiently, with some improvements proposed to enhance efficiencies and further benefit the Northern Ireland consumer.

The proposed amendments will not change any decision-making rights or TIA principles but will provide more clarity for both organisations.

We are now consulting on the proposed amendments.

The SONI Proposed Amendment Report (as agreed with NIE Networks) contains proposed amendments to TIA Sections B and U.

The NIE Networks Proposed Amendment Report (as agreed with SONI) contains proposed amendments to TIA Sections C, D and U.

SONI and NIE Networks would welcome any feedback or comments on the proposed changes by the 31st July at 12.00 noon. Please email

All comments will be reviewed jointly by SONI & NIE Networks and a final report will be forwarded to The Utility Regulator for Northern Ireland.