The gas distribution sector has a well-developed safety risk-based approach to prioritising iron mains replacement expenditure, accepted by the HSE as a robust method of reducing societal risk from network gas escapes.
However, a revised three-tier approach, introduced as a key element of the RIIO-GD1 price control, allows gas distribution network operators (GDNs) greater flexibility and potential optimisation of replacement scheme design through incorporation of condition, environmental impact and customer service metrics, subject to overall network safety risk reduction targets being met.
A multi-criterion risk-based approach to investment planning has been adopted by the UK water industry which has not been dominated to the same extent by safety considerations. As a result the water industry already considers a broader suite of business and societal risks.
This project has identified transferable methods of investment planning from water to gas distribution which incorporate multi-criterion risk-based approaches. We have devised a robust decision support procedure (DSP) which helps GDNs deliver a more cost-effective investment plan for iron mains replacement, whilst still meeting their safety risk reduction obligations.