Mix it up

Cadent and Northern Gas Networks are pioneering the injection of hydrogen into the gas grid with the HyDeploy project. Here's the inside story.

Mix it up

Climate change has been described as one of the greatest threats to humanity. Like many countries around the world, the UK has responded by committing itself to tough reductions in carbon dioxide emissions.

But while efforts to decarbonise electricity generation have made significant progress, the decarbonisation of Britain’s heat and transport sectors have lagged behind.

However, a groundbreaking initiative could be about to change that.

This year, Cadent, Britain’s biggest gas distribution network, along with Northern Gas Networks (NGN) and the HyDeploy consortium started a pioneering three-year project at Keele University.

The project is designed to demonstrate that a blend of hydrogen – which emits no carbon dioxide when burnt – and natural gas can be distributed and used safely and efficiently in a live part of the distribution network without disruptive changes for customers – and at the same time cut carbon dioxide emissions.

It will be the first time that a hydrogen blend has been used in a live distribution network since Britain’s conversion from town gas to natural gas.

The project was awarded £6.7 million from the Network Innovation Competition (NIC) last November and a further £760,000 was funded by Cadent Gas and NGN.

The challenge

Like most other countries around the world, the UK recognises the challenge of climate change. Not only has it resolved, by 2050, to reduce carbon emissions by 80% of their level in 1990, but it has also made it a legal obligation under the Climate Change Act  (2008).

Although significant progress is being made towards a low-carbon future in electricity generation, the projected carbon emissions reductions for the heat and transport sectors are minimal.

This is an ideal opportunity for “first of their kind” projects such as HyDeploy to show how repurposing of the gas grid can play a significant role in decarbonising heat.

It makes considerable sense both from an economic and engineering perspective to use the gas grid as the vector to decarbonise heat. The gas network is designed to deliver gas safely and reliably to more than 23 million customers and over 83% of homes are connected to the gas network.

The gas grid is a world class infrastructure that has received decades of investment from consumers and stretches the length and breadth of the country.

The gas network can meet a 1-in-20 peak day demand – a winter defined as the worst in 20 years. At these winter peaks, the gas networks can transport four times as much energy as the electricity network.

Cadent’s London network alone provides 24GW at peak hours, which would require the equivalent output of seven Hinckley Point C nuclear power stations if heat were electrified, not to mention the significant extra network infrastructure investment that would be needed.

Peak heat demand across the UK is about 300GW (peak half-hour). To supply this amount of heat through the electricity network, even with effective heat pumps, would require an electrical system (either generation, or generation plus storage) with capable of delivering 100GW more than existing electrical demand – which is typically between 25 and 50GW.

The investment required to upgrade the electricity network to cater for the peak heat demand that is met by today’s gas grid would run into the many billions and this cost would be borne by UK consumers.

The mix

Today, 99% of our domestic gas is traditional natural gas, with about 1% biomethane from anaerobic digestion (AD).

However, if we are serious about decarbonising heat and meeting the UK’s carbon emission reductions, we must think of other forms of low-carbon or zero-carbon gases to replace natural gas. This will mean the increasing use of gases such as bio substitute natural gas (BioSNG), hydrogen and increased amounts of biomethane in the gas network.

To enable these new sources of gas to be injected onto the network, our current regulations must change.

The HyDeploy project will seek an exemption from the Gas Safety (Management) Regulation (GS(M)R) to allow potentially up to 20% of the volume of gas in the Keele network to be hydrogen. GS(M)R) currently only allows 0.1% of gas volume in the network to be hydrogen, despite the network formerly distributed town gas that was 40-60% hydrogen.

The GS(M)R was developed during the discovery of significant quantities of North Sea gas which, at the time, would supply the UK for the foreseeable future. With diminished supplies of North Sea gas and the advent of low-carbon forms of gas, including hydrogen, this will require an update to the GS(M)R.

There are some other considerations related to the flow weighted average calorific value (FWACV); and the way that energy content has to be average across the local distribution zone (LDZ). Currently, this would mean hydrogen would have to be  further processed by adding propane. Recommendations for updating the current regime are being investigated in a separate Cadent NIC project called Future Billing Methodology (for more information see www.futurebillingmethodology.co.uk).

The HyDeploy programme

HyDeploy is being hosted by the University of Keele, on the outskirts of Newcastle-Under-Lyme in Staffordshire. It is the UK’s largest campus university, and has 12,000 students and staff, of which 5,000 live on site.

The campus building have a variety of uses, including academic, business, commercial, retail, leisure and residential. These demands are serviced by the university’s own private utility network, which makes it possible to use the campus as a “living laboratory” on the scale of a small town.

This mix of uses, ownership of a private network, an established range of renewable energy sources and the scale of the campus – allied to the university’s expertise in sustainability and green technologies – offers a unique opportunity to develop an “at-scale demonstrator” for smart energy technologies and, therefore, to host the HyDeploy project.

The project is broadly split into three phases, each one lasting about a year.

During phase one, The HyDeploy consortium, led by Cadent, NGN and Keele University, will be engaging extensively with customers on the Keele site. Every appliance and installation will be baseline surveyed and tested locally on natural gas and hydrogen blends, including supporting offline laboratory tests.

The network will be surveyed, modelled and operational procedures for leak detection and management processes established. This will include training of operational staff from both Keele and Cadent, who maintain the site.

The evidence base will collated and a quantitative risk assessment undertaken to seek an exemption to GS(M)R. This exemption will be given by the Health and Safety Executive (HSE), providing it is satisfied that the hydrogen blend meets their rigorous safety requirements for gas.

Subject to the HSE giving the green light, phase two will begin. This will involve the installation of onsite hydrogen production, injection plant and network monitoring. The hydrogen production and injection plant will able to deliver up to 20% hydrogen onto the network in accordance with the exemption. On the network itself there will be static and mobile sample points and compositional, pressure and flow analysis facilities installed.

In phase three, the blended hydrogen will flow into customers’ appliances. An extensive trial programme will be undertaken to confirm, understand and document the operational behaviour of the network and appliances, validating network modelling and developing best practice for network management. The results from the HyDeploy project will be disseminated to ensure all stakeholders can benefit from this work and that it can be built upon in the near future with a trial on the public network.

The benefits of hydrogen blend

Both Cadent and NGN are seeking to make best use of the gas network to support a low-carbon economy and to help the UK meet its emission targets. Blending hydrogen at 20% volume would create up to 29TWh of low-carbon heat a year.

This is significantly more than the existing Renewable Heat Incentive is projected to deliver, with the potential to unlock further savings as the technologies and regulatory system develop.

If the gas network is not used to deliver low-carbon heat to the customer, other technologies must be found to meet the equivalent heat demand. One of the proposed technologies is heat pumps – heat pumps play an important role in all of National Grid’s Future Energy Scenarios (FESs).

The rollout of heat pumps will require significant consumer outlay and disruption in consumers’ homes, neither of which are necessary with hydrogen blending because it will use an existing gas network that has been invested in over many decades.

The projected saving of using blended hydrogen at 20% volume rather than air source heat pumps would be as much as £8 billion by 2050, if they are to deliver the equivalent amount of low-carbon heat.

Analysis by the National Grid FES team has evaluated the carbon savings expected by blending hydrogen into the distribution system. The analysis has shown that, by 2050, decarbonisation of the gas network by using a hydrogen blend has the potential to prevent the emission of 119 million tonnes of carbon dioxide equivalent on a cumulative basis.

The project partners

One important element of the project is the collaboration between the different partners involved. This project is a true collaboration between two gas distribution networks and the first time it has happened at the bid stage in the Network Innovation Competition.

Cadent Gas is the funding licensee and project sponsor, and NGN is the collaborating gas distribution network. Keele University is the site sponsor, host network and academic collaborator.

The Health and Safety Laboratory (HSL) is one of the UK’s leading health and safety experimental research establishments and will be responsible for the scientific and experimental programme. ITM Power is uniquely experienced in hydrogen grid injection projects and will supply the hydrogen production plant. Progressive Energy has a track record in undertaking NIC projects and is responsible for day-to-day Project management, co-ordination and planning.

Also, there are organisations that will be supporting the HyDeploy programme, including Dave Lander consulting, Kiwa Gastech and Otto Simon.

Andy Lewis, innovation portfolio manager, future of gas, Cadent


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