Future Network Planning

Since 2025, GMO NI has taken on responsibility for gas network planning in Northern Ireland.

Working collaboratively with TSOs, we develop and publish:

• Gas Transmission Outlook – a 10-year view of the network
• Energy Horizons Report – a long-term outlook to 2050 (first edition due 2027)

Through a formal Memorandum of Understanding with SONI, the electricity transmission system operator, these plans take a whole-system approach, supporting:

• Security of supply
• Decarbonisation
• Long-term infrastructure planning

Understanding Today, Planning for Tomorrow.

Northern Ireland Gas Transmission Outlook (NI GTO) 2025/26

This is the inaugural version of the Northern Ireland Gas Transmission Outlook (NI GTO) which is published in accordance with condition 2.13 (Network Forecasts) of the TSO’s gas conveyance licences. The NI GTO provides a ten-year outlook of transmission network requirements and replaces the previous Northern Ireland Gas Capacity Statement (NI GCS).

Mutual Energy Limited (MEL) and GNI (UK) Limited, working together through the Gas Market Operator for Northern Ireland (GMO NI), are responsible for gas transmission network planning in Northern Ireland. As the energy system evolves, planning must adapt.

The Climate Change Act (Northern Ireland) 2022 sets legally binding targets, including net zero emissions by 2050 and at least 80% renewable electricity by 2030. Delivering the energy transition requires coordination across all energy systems and therefore it is important that gas network operators work collaboratively with SONI to align planning where appropriate to support the efficient development of future energy infrastructure.

The NI GTO will continue to evolve, supporting informed decision-making and confidence in the transition to net zero.

The NI GTO 2025-26, along with previous editions of the Northern Ireland Gas Capacity Statement are available below.

Charting Northern Ireland’s Energy Transition to 2050

To complement the Gas Transmission Outlook, the TSOs are developing a new long‑term planning publication: Energy Horizons.

Published every 2–3 years, Energy Horizons will provide a strategic view of how Northern Ireland’s energy system could evolve over the next 25 years. It will:

• Analyse long‑term supply and demand dynamics
• Identify credible decarbonisation pathways
• Evolve continually, informed by the latest observable evidence
• Be produced alongside SONI’s Tomorrow’s Energy Scenarios (TES)
• Strike a clear balance between ambition and practicality

Energy Horizons will support strategic decision‑making today by clearly setting out the choices, risks, and opportunities that will shape Northern Ireland’s energy system to 2050.

Biomethane Overview

Biomethane is a renewable, low-carbon gas produced from organic materials such as agricultural and food waste through anaerobic digestion.

In December 2022, the Transporter introduced arrangements to facilitate the injection of biomethane into the Northern Ireland (NI) Transmission System. These arrangements support the integration of renewable gas into the network.

Further information on connecting biomethane facilities to the NI Transmission System is available in the guide below.

The Transporter has developed draft Transmission biomethane Business Rules to support the introduction of biomethane injection to the NI Transmission System.

These draft Business Rules set out the principles and processes required to accommodate biomethane, including new and amended arrangements for market participants.