Jan 2018
Gas Distribution and Gas Transmission
Jan 2018
Dec 2020
Cadent, SGN and Wales and West Utilities
Northern Gas Networks Innovation Team
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Network Innovation Competition
Gas Distribution Networks
The UK, as with most other countries around the world, recognises the challenge of climate change and has resolved, by 2050, to reduce carbon emissions by 80% of their level in 1990. In the UK this is a legal obligation defined under the terms of the Climate Change Act 2008. Climate change is one of the most significant technical, economic, social and business challenges facing the world today. Following the completion of the H21 LCG NIA project there has been growing interest in the opportunity to decarbonise the gas network by converting to 100% hydrogen, a solution that appears to be technically and economically viable.

Decarbonising UK heat, which is predominantly provided by the gas network, is particularly difficult due to the large inter-seasonal swings in demand, distributed nature of the consumer appliances (boilers, fires, ovens etc.) making localised decarbonisation impractical, and established significant customer preference within the UK. Decarbonising the gas network with hydrogen has the potential to be the single biggest contribution to the deliverability of the Climate Change Act.

All the technology to convert the UK gas distribution network to hydrogen can be evidenced across the world today (steam methane reformers, salt caverns, hydrogen appliances). However, the primary obstacle to progressing with such a decarbonisation pathway is the lack of quantitative safety evidence. The H21 LCG study has confirmed the below 7 bar UK gas distribution network has adequate capacity with minor reinforcement for conversion (the above 7 bar would not be effected). However, a significant programme of work is required to prove this part of the gas network in its 2032 condition, i.e. following completion of the Iron Mains Replacement Programme, presents a comparable and acceptable risk whether transporting 100% hydrogen or natural gas.

Quantifying this risk is a significant challenge, the range of below 7 bar asset in the UK gas networks in 2032 including pipe, fittings, connections, district governors (pressure control equipment) etc is extensive. Designing an appropriate testing regime that provides confidence that this range of assets is safe operating on 100% hydrogen is a challenge which requires a dedicated programme of strategically targeted work, large amounts of funding and high levels of expertise.  
The H21 LCG report recommends circa £100m of funding is required to de-risk a hydrogen for heat pathway. This can be broken down into three core evidence requirements; safety, customer acceptability and Front End Engineering Design. This was set out in the `H21 - Executing the roadmap' document presented to OFGEM and BEIS in December 2016. The H21 NIC project will provide the safety based evidence part of the roadmap. This project is the first NIC project that has been collaboratively funded, supported and, subject to successful award, executed across all GDNs.

The below 7 bar UK gas distribution network in 2032 will be predominantly polyethylene (circa 90%). However, there will still be some retained metallic iron and steel mains. Furthermore there will be a range of different PE pipe ages, transition fittings (between PE, iron, steel, different diameters etc.), services, service connections, buried valves, service governors and district governors.