SONI to deliver major projects at Coolkeeragh to ensure security of electricity supply

SONI, which runs the the NIE-owned transmission network, has listed a 110 kilovolt extension to the Derry power plant in its Forward Work Plan for 2023/24.

It says the project at Coolkeeragh, owned by ESB, will facilitate ‘renewable integration and security of supply’.

“This project will facilitate the future connection of a third interbus transformer, the restoration of the second busbar coupler and section switches and other improvements.

“SONI received approval for the Transmission Network Preconstruction Project (TNPP) submission in March 2023. SONI is progressing site investigations (to determine treatment options) through our environmental consultant,” newly-published documents from the SONI Forward Work Plan 2023-24 explain.

Pre-construction work is expected to commence in May 2024 with project completion scheduled for 2029.

SONI says the cost scale for the project will be medium.

"SONI will be working in collaboration with NIE Networks as the programme of activities develops in order to make improvements to the Transmission System which will enhance grid security.

"SONI is engaged with the Utility Regulator in our regular monthly meetings where we provide updates on the project and use the opportunity to enter into discussion on any challenges that we may face or mitigations we are taking on projects. SONI will continue to engage with the UR,” the documents state.

A 275 kV substation at Coolkeeragh, meanwhile, is among five in the north that will require redevelopment, SONI has confirmed, with the cost estimated as low.

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"An appraisal of the original design using modern standards has found that the concrete structures at Castlereagh, Coolkeeragh, Kells, Magherafelt and Tandragee whilst sufficient to meet expected mechanical loading under a fault, would lead to deflections beyond standard.

"This is being managed through additional inspections by NIE Networks. Long-term refurbishment of the five substations is required.

“The key activities over the 2023/24 period will be:

• Magherafelt and Coolkeeragh 275kV Consultant procurement towards option appraisal

“Agree option appraisal scope of works required with NIE Networks for

“Coolkeeragh and Magherafelt and commence the progression of procurement and award of contract for optioneering with the substation design consultant.”

SONI says the driver for the project is security of supply.

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