H21: Pioneering a UK hydrogen network

H21: Pioneering a UK hydrogen network

Can existing gas networks in the UK be repurposed to safely carry 100% hydrogen in order to reduce carbon dioxide emissions from heat?

That’s the question a suite of innovation projects led by Northern Gas Networks (NGN) is aiming to answer.

As the UK looks towards 2050 and a cleaner and greener energy future, the issue of decarbonising the way the country heats its homes and businesses needs to be addressed.

But decarbonising heat presents a very large and difficult problem. The scale of energy the UK requires is 540 terrawatt hours (TWh) and the enormous swings in demand from summer to winter mean that just using electricity is not a realistic solution.

For more than a century the UK has been heavily reliable on gas: it provides flexible energy at huge scale that can be stored in gigantic volumes indefinitely to be used when needed.

The UK also has an existing network in place that is used by 90% of homes, businesses and industry for heat.

Replacing the gas in the networks with a low carbon fuel like hydrogen is a solution that can deliver the carbon savings the UK needs within the time scales required by the Climate Change Act and Paris Agreements.

“A hydrogen gas grid makes use of an existing reliable and resilient asset, which avoids the need for major disruption in customers’ homes or highways, and maintains energy choice for consumers.”

Part of the H21 initiative is examining the supporting production, storage and metering requirements to deliver a hydrogen network, as well as gathering essential evidence proving that a hydrogen gas network is equally as safe as the natural gas network heating homes today.

“While great strides have been made to decarbonise the power sector over the last few years, how we decarbonise heat remains uncertain,” Tim Harwood H21 Programme Director, NGN, explained to H2 View.

“Heat currently contributes around a third of UK emissions. As hydrogen is zero carbon at the point of use, a hydrogen gas grid would make significant inroads into carbon targets.”

“A hydrogen gas grid makes use of an existing reliable and resilient asset, which avoids the need for major disruption in customers’ homes or highways, and maintains energy choice for consumers.”

The H21 journey began with the H21 Leeds City Gate project which proved the UK gas networks could be converted to hydrogen.

“This was a feasibility study delivered by NGN in partnership with Wales & West Utilities, Kiwa Gastec and Amec Foster Wheeler,” Harwood said.

“Based on the city of Leeds, which acts as a representative example of the UK due to its population size and complex gas network, the H21 Leeds City Gate project proved that it is technically possible and economically viable to convert the existing gas network to carry 100% hydrogen.”

The next step is to gather quantified safety evidence necessary to inform a government decision on hydrogen for use in the existing gas network, which NGN is currently doing through its H21 Network Innovation Competition (NIC) project.

Split into two phases, Phase 1A aims to establish whether there will be any changes in leakage levels to the UK’s low/medium/intermediate pressure gas distribution network assets when pressurised with 100% hydrogen.

A purpose-built testing facility (pictured below) was opened last month at the Health and Safety Executive’s (HSE) Science and Research Centre in Buxton, Derbyshire.

“It’s the world’s only 100% hydrogen testing facility and will carry out controlled testing of a huge range of assets – network pipes, valves, joints and fittings – from across the entire UK gas network to understand how they would operate with 100% hydrogen flowing through, and how that compares to their operation with natural gas,” Harwood said.

© Northern Gas Networks

Phase 1B will involve consequence testing and ignition testing trials at DNV GL’s research centre at RAF Spadeadam in Cumbria, examining various characteristics of how hydrogen behaves in comparison to natural gas.

“NGN expects to share definitive findings of both phases in 2020. The next steps would then naturally be finding an unoccupied test site with above and below ground assets for further research trials,” Harwood said.

Assuming success, and backed by a supporting government policy decision on hydrogen’s use for heat, a blueprint for converting the North’s major cities is set out in the H21 North of England report.

This detailed engineering scenario was launched last November by NGN, in partnership with Norwegian energy giant Equinor and UK gas distributor Cadent.

This conversion process would take place over seven years from 2028 to 2034 during the summer months and would include the cities of Leeds, Bradford, Wakefield, Huddersfield, Hull, Liverpool, Manchester, Teesside, Tyneside and York.

The design incorporates a 12 gigawatt (GW) hydrogen production facility, which would deliver 85TWh of hydrogen annually, along with 8TWh of interseasonal storage.

The captured carbon dioxide would be transported offshore for storage in a 20 million tonnes per annum carbon capture and storage (CCS) scheme.

“In terms of carbon savings, the H21 North of England report calculates that 20 million tonnes of carbon could be saved annually by converting the major cities of the North to 100% hydrogen and CCS technology – equivalent to taking 3.3 million cars off our roads every year,” Harwood highlighted.

As the gas distributer for the North, NGN is actively exploring cutting-edge thinking and world class science through its energy futures projects, which as well as H21 includes the Cadent-led blended hydrogen programme HyDeploy, and whole systems facility InTEGReL.

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