Modifications to additional RIIO-3 associated documents

Details of outcome

In December 2025 and February 2026 we consulted on a number of associated documents, which set out the detailed methodologies and guidance that support the licence conditions required to implement the RIIO-3 price control settlement for electricity transmission, gas transmission and gas distribution networks. The consultations closed on 16 January 2026 and 26 February 2026 respectively. Following careful consideration of responses, we have decided to implement the associated documents as set out in the notices below. The associated documents will come into effect on 1 April 2026.  

Read the full outcome 

Note: some of the files attached below are not fully accessible. If you require an alternative format, please contact RIIO3@ofgem.gov.uk.  

Read the guidance 

Network price control 2026 to 2031 (RIIO-3) guidance

Electricity transmission price control 2026 to 2031 (RIIO-ET3) guidance

Gas distribution price control 2026 to 2031 (RIIO-GD3) guidance

Gas transmission price control 2026 to 2031 (RIIO-GT3) guidance

Original consultation

Consultation description 

This consultation sets out the proposed changes to five associated documents supporting the gas distribution and gas transmission licences: 

• Decarbonisation project development ‘use it or lose it’ (UIOLI) governance document
• Small decarbonisation projects re-opener governance document
• Collaborative streetworks financial output delivery incentive (ODI-F) governance document
• Vulnerability and carbon monoxide Initiatives UIOLI governance document
• Terms of reference for the Digital Platform for Leakage Analytics working group 

These five associated documents are in addition to the associated documents consulted upon alongside the RIIO-3 licences. 

Who should respond 

We welcome responses from: 

• gas transmission network operators
• gas distribution network operators
• anyone with an interest in the RIIO-3 price control