Strengthening RIIO-GD3 submission through structured planning

Published: 22 September 2025

If you’re preparing a RIIO-GD3 business plan, you need a clear strategy to secure a significant amount of funding and meet Ofgem’s strict requirements.

Cadent Gas faced that test for its 2026–2031 submission. They had to tie investment needs to their corporate goals while data, evidence, and risk justification were under heavy scrutiny. Group company Aqua Consultants joined Cadent's team to frame strategy, shape regulatory cases, and align every datapoint in preparing their submission.

Approach and implementation

Aqua Consultants embedded in Cadent’s team from day one. They framed the plan around Cadent’s corporate strategies, matching each investment case to long-term objectives. This led to the creation of ten Engineering Justification Papers and four Major Project Justification Papers, guiding the team through cost-risk trade-offs and technical evidence standards.

They acted as a critical friend. They challenged weak assumptions, tightened narrative and sharpened the link between need, solution, and benefit. In doing so, they managed the programme end to end: setting the delivery roadmap, producing and checking all data tables, and keeping a transparent audit trail for every assumption and source.

When Ofgem issued its draft determination, Aqua Consultants ran a structured analysis of the feedback. Following that, they updated Engineering Justification Papers, Major Project Justification Papers, and data tables, then coordinated Cadent’s formal response and stakeholder governance.

Impact and outcomes

Cadent Gas achieved an outstanding rating in Ofgem’s July 2025 draft determination. Ofgem praised the clarity of Cadent’s investment cases and the strength of its data assurance.

This helped Cadent Gas to secure approval for funding for reinforcement and replacement expenditure. The rigorous cost-risk analysis in each justification paper won regulator trust and stakeholder buy in. Cadent Gas now has a clear, risk-based path to respond to final determinations and move into delivery.

Outstanding rating on the RIIO-GD3 draft determination
Formal approval in network investment
Robust audit trail for all data and assumptions
Structured response plan for Ofgem feedback

“Aqua Consultants were a real asset during the development of our RIIO-GD3 plan. They brought regulatory insight and business planning expertise, but more than that, they got stuck in and worked alongside us. Their flexible, hands-on support helped us tackle challenges and build a confident, high-quality submission.”

Sam Wilson

Head of Strategic Investment Planning, Cadent Gas