RIIO-3 Draft Determinations for the Electricity Transmission, Gas Distribution and Gas Transmission sectors

Related links

• RIIO-3 Sector Specific Methodology Decision for the Gas Distribution, Gas Transmission and Electricity Transmission Sectors
• RIIO-3 Sector Specific Methodology for the Gas Distribution, Gas Transmission and Electricity Transmission Sectors

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RIIO (Revenues = Incentives + Innovation + Outputs) is our framework to ensure that the monopoly companies operating our gas and electricity networks have sufficient revenue to run and invest in networks that efficiently deliver what customers value. 

The current electricity and gas transmission and gas distribution price controls (known as RIIO-2) end on 31 March 2026. The next price control (RIIO-3) will run for five years, from 1 April 2026 to 31 March 2031. 

Following our review of the RIIO-3 business plans submitted by the network companies in December 2024, we are now consulting on our Draft Determinations for RIIO-3.

Please send all responses by 26 August 2025 to RIIO3@ofgem.gov.uk.

Main document

[RIIO-3 Draft Determinations - Overview [PDF, 1.18MB]

](https://www.ofgem.gov.uk/sites/default/files/2025-06/Draft-Determinations-Overview-Document.pdf)

Subsidiary documents

[RIIO-3 Draft Determinations - Finance Annex [PDF, 2.13MB]

](https://www.ofgem.gov.uk/sites/default/files/2025-06/Draft-Determinations-Finance-Annex.pdf)

[RIIO-3 Draft Determinations - ET Annex [PDF, 1.76MB]

](https://www.ofgem.gov.uk/sites/default/files/2025-06/Draft-Determinations-Electricity-Transmission.pdf)

[RIIO-3 Draft Determinations - NGET Annex [PDF, 792.95KB]

](https://www.ofgem.gov.uk/sites/default/files/2025-06/Draft-Determinations-NGET.pdf)

[RIIO-3 Draft Determinations - SHET Annex [PDF, 512.04KB]

](https://www.ofgem.gov.uk/sites/default/files/2025-06/Draft-Determinations-SHET.pdf)

[RIIO-3 Draft Determinations - SPT Annex [PDF, 421.38KB]

](https://www.ofgem.gov.uk/sites/default/files/2025-06/Draft-Determinations-SPT.pdf)

[RIIO-3 Draft Determinations - GD Annex [PDF, 1.67MB]

](https://www.ofgem.gov.uk/sites/default/files/2025-06/Draft-Determinations-Gas-Distribution.pdf)

[RIIO-3 Draft Determinations - Cadent Annex [PDF, 712.24KB]

](https://www.ofgem.gov.uk/sites/default/files/2025-06/Draft-Determinations-Cadent.pdf)

[RIIO-3 Draft Determinations - NGN Annex [PDF, 411.27KB]

](https://www.ofgem.gov.uk/sites/default/files/2025-06/Draft-Determinations-NGN.pdf)

[RIIO-3 Draft Determinations - SGN Annex [PDF, 503.03KB]

](https://www.ofgem.gov.uk/sites/default/files/2025-06/Draft-Determinations-SGN.pdf)

[RIIO-3 Draft Determinations - WWU Annex [PDF, 470.68KB]

](https://www.ofgem.gov.uk/sites/default/files/2025-06/Draft-Determinations-WWU.pdf)

[RIIO-3 Draft Determinations - GT Annex [PDF, 1.29MB]

](https://www.ofgem.gov.uk/sites/default/files/2025-06/Draft-Determinations-Gas-Transmission.pdf)

[RIIO-3 Draft Determinations - Impact Assessment [PDF, 673.60KB]

](https://www.ofgem.gov.uk/sites/default/files/2025-06/RIIO-3-Draft-Determinations-Impact-Assessment.pdf)

[Independent Report on Ongoing Efficiency [PDF, 702.58KB]

](https://www.ofgem.gov.uk/sites/default/files/2025-06/Independent-Report-on-OE_27-June-2025.pdf)

[RIIO-3 Draft Determinations - Consolidated Questions [PDF, 328.04KB]

](https://www.ofgem.gov.uk/sites/default/files/2025-06/RIIO-3-Draft-Determinations-Consolidated-Questions.pdf)

[RIIO-3 Draft Determinations Business Plan Financial Models [ZIP, 49.02MB]

](https://www.ofgem.gov.uk/sites/default/files/2025-06/RIIO-3%20Draft%20Determinations%20Business%20Plan%20Financial%20Models.zip)

Response documents

[RIIO-3 Draft Determinations email responses [PDF, 555.03KB]

](https://www.ofgem.gov.uk/sites/default/files/2025-10/RIIO-3_Draft_Determinations_email_responses.pdf)

[RIIO-3 Draft Determinations responses [ZIP, 36.33MB]

](https://www.ofgem.gov.uk/sites/default/files/2025-10/RIIO-3%20Draft%20Determinations%20responses.zip)

[Cadent RIIO-3 Draft Determinations response [ZIP, 34.41MB]

](https://www.ofgem.gov.uk/sites/default/files/2025-10/Cadent%20RIIO-3%20Draft%20Determinations%20response.zip)

[NGET RIIO-3 Draft Determinations response [ZIP, 16.78MB]

](https://www.ofgem.gov.uk/sites/default/files/2025-10/NGET%20RIIO-3%20Draft%20Determinations%20response.zip)

[NGT RIIO-3 Draft Determinations response [ZIP, 20.33MB]

](https://www.ofgem.gov.uk/sites/default/files/2025-10/NGT%20RIIO-3%20Draft%20Determinations%20response.zip)

[SGN RIIO-3 Draft Determinations response [ZIP, 7.81MB]

](https://www.ofgem.gov.uk/sites/default/files/2025-10/SGN%20RIIO-3%20Draft%20Determinations%20response.zip)

[SHET RIIO-3 Draft Determinations response [ZIP, 46.46MB]

](https://www.ofgem.gov.uk/sites/default/files/2025-10/SHET%20RIIO-3%20Draft%20Determinations%20response.zip)

[SPEN RIIO-3 Draft Determinations response [ZIP, 17.44MB]

](https://www.ofgem.gov.uk/sites/default/files/2025-10/SPEN%20RIIO-3%20Draft%20Determinations%20response.zip)

[NGN RIIO-3 Draft Determinations response [ZIP, 21.28MB]

](https://www.ofgem.gov.uk/sites/default/files/2025-10/NGN%20RIIO-3%20Draft%20Determinations%20response.zip)

[WWU RIIO-3 Draft Determinations response [ZIP, 40.03MB]

](https://www.ofgem.gov.uk/sites/default/files/2025-10/WWU%20RIIO-3%20Draft%20Determinations%20response.zip)

Related links

• RIIO-3 Sector Specific Methodology Decision for the Gas Distribution, Gas Transmission and Electricity Transmission Sectors
• RIIO-3 Sector Specific Methodology for the Gas Distribution, Gas Transmission and Electricity Transmission Sectors

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