Security of supply and the role of Mutual Energy’s assets

As the energy transition progresses, Stephen Hemphill at Mutual Energy explores how key infrastructure will be critical to meeting consumer energy needs.

Mutual Energy manages essential electricity and gas infrastructure on behalf of Northern Ireland consumers. The company owns and operates two vital energy links between Northern Ireland and Great Britain: the Moyle electricity interconnector and the Scotland to Northern Ireland gas transmission pipeline (SNIP). These assets play a key role in maintaining security of energy supply.

Security of supply

All Northern Ireland’s natural gas is sourced from the National Gas Transmission System in GB. It can be transported by two routes: the SNIP which runs from Twynholm in Scotland to Islandmagee in Northern Ireland, or the Irish interconnector to Gormanston and then via the South North Pipeline. Almost all of the gas used in Northern Ireland is imported via the SNIP, due to its lower transportation costs.

Whilst annual consumption of gas is expected to decline, peak demand for gas will continue to grow, for two reasons:

1. Northern Ireland relies on natural gas for dispatchable power generation; and
2. connections to the gas network continue to increase (reducing carbon emissions by replacing old oil-fired boilers).

With the closure of the Kilroot coal units, Northern Ireland is increasingly reliant on gas-fired dispatchable generation, supplemented with electricity imports to maintain security of electricity supply. When renewable generation output is low for extended periods, combined cycle gas turbines at Ballylumford and Coolkeeragh power stations provide efficient dispatchable base load generation. New open cycle gas turbines at Kilroot power station support the system when the output from renewables reduces for shorter time periods, or at short notice. In a winter Dunkelflaute event (a period of high meteorological pressure bringing back-to-back days of low renewable generation) electricity demand will be reliant on gas-fired generation and electricity imports to ‘keep the lights on’.

As an example of Northern Ireland’s growing reliance on gas-fired generation and electricity imports, the first Dunkleflaute of winter 2025/26 that occurred 10-16 October 2025 resulted in over 95% of Northern Ireland’s fuel mix being met via Mutual Energy’s gas transmission and electricity assets.
How Mutual Energy is supporting the energy transition

In the absence of the development of extensive energy storage capacity and renewable gas production in Northern Ireland (i.e. biomethane and hydrogen), reliance on gas fired power generation will require further investment in natural gas infrastructure. To decarbonise our energy system and reduce reliance on natural gas, Mutual Energy is supporting the development of renewable gases in Northern Ireland.

In conjunction with the other Northern Ireland gas network operators, we have recently completed a study to investigate how the gas network needs to evolve to accommodate widespread injection of biomethane. Developing large-scale indigenous biomethane production will reduce reliance on gas imports from GB, as well as providing an alternative pathway for decarbonising heat, supplementing electrification, and reducing winter peak electricity demand.

We have also been developing the concept of a Greater Belfast Hydrogen Hub. Green hydrogen production, utilising offshore wind generation, could be connected to salt cavern storage, all located near Larne. This store could then be connected to two out of three of Northern Ireland’s power stations, as well as to an industrial cluster in Belfast via a c. 35km pipeline. The cluster could support e-fuel production, providing decarbonised fuel for aviation and shipping in Northern Ireland.

While it’s important to look to the future, it is essential to be sensible and pragmatic about the present. As a company, we have a responsibility to ensure robust gas and electricity supplies to Northern Ireland are maintained. Investment in our existing infrastructure assets therefore remains vital and will ensure they continue to operate reliably over the coming years, helping Northern Ireland to deliver a safe and secure energy transition.

Stephen Hemphill
Chief Operating Officer
Mutual Energy

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