The use of hydrogen as an alternative to natural gas is key to ensuring that energy demands of the future are met for heat, power and transport whilst achieving net zero. In order to transport hydrogen throughout the UK, compression will be required. The project will evaluate the costs and opportunities to repurpose the existing compression equipment to keep costs to a minimum for gas consumers.
A technical demonstration will be conducted, at FutureGrid and will provide a facility for any future work as an outcome of this project, whilst enabling the facility to demonstrate further capability such as PIGing and alternative metering systems. The facility will demonstrate a whole systems approach; using an electrolyser to produce hydrogen which will be stored on site and used to power the compression systems during the demonstration. The compression loop will compress and transport hydrogen gas, to demonstrate the compatibility of typical National Transmission System (NTS) components. The system will be connected to NGN's H21 project, demonstrating the use of hydrogen in a distribution system including domestic use.
NGN and SGN will support the project by contributing to meetings and evidence gathering, as compression may be required on the distribution networks in the future.
Siemens Energy have knowledge and experience of the compressors, gas turbines and associated equipment currently used on the NTS as they have supplied several compressor systems which are currently installed on the NTS. They are therefore best placed to investigate the capabilities of the systems currently installed and the potential modifications required to enable them to compress hydrogen.
DNV will be key to demonstration of the compression system, which will take place at DNV's test facility at Spadeadam. DNV have extensive experience of gas pipelines, large scale testing and of the current compression systems installed on the NTS, and are therefore an ideal partner to develop the testing requirements for the system.
ITM Power have the largest electrolyser manufacturing facility in the world and are ideally placed to supply the electrolyser for production of hydrogen at Spadeadam, which will be used to power the compressor during demonstration.
As the gas industry moves towards the use of hydrogen, there will likely be a requirement for hydrogen production facilities throughout the UK. This may mean that compression will be required on the local transmission systems, not just the NTS, to move the hydrogen through the pipelines after production.
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Problem Bring Solved
The hydrogen strategy released by the UK government in August 2021 stated that in order to support the net zero targets of 2050, by 2030 there is an ambition to produce 5GWs of low carbon hydrogen. This ambition to provide low carbon hydrogen as a part of a suite of net zero energy sources provides clear guidance to the UK gas networks to progress our hydrogen transportation capability. The national transmission system (NTS) provides a supply of gas to 40 power stations, large industrial users and gas distribution networks from natural gas terminals situated on the coast. The NTS provides a resilient supply of natural gas today and aims to provide the same capability for hydrogen, especially in light of the variability in green hydrogen production.
In order to move the gas through the NTS a compression system is required. Hydrogen has different properties to natural gas and in order to compress the equivalent gas the power input will need to increase, approximately by a factor of 10.
The first step is to understand the capability of the turbine to utilise hydrogen as a fuel gas, reducing emissions and eliminating the need to store natural gas as a fuel on site. We have begun work on this through NIA and will leverage the output of this project to provide insight into this feasibility study. The next step is to consider the compression opportunity with various hydrogen blends in order to provide the most cost-effective solution which is the focus of this work.
The production of hydrogen and injection into the NTS is likely to be inconsistent due to weather fluctuations and varying demand, therefore we will need to understand how the system can manage variable blends of hydrogen and methane. This is likely to increase the cost of the system as variable compressors may be required.
Each compressor on the network would cost at least £40m to replace. Across 24 compressor stations, there are currently 70 compressors. The project will consider the opportunity to repurpose the current compression assets for use with hydrogen and the system modifications which would be required. Determining the most cost effective and efficient route to compress hydrogen is vital to keep costs at a minimum for the NTS transition, and therefore energy customers, through to 2050.
Impacts and benefits
Determining the most cost-effective route to compression for consumers is vital to enable the energy transition and to provide energy system resilience to all energy users in the UK. The largest cost associated to repurposing NTS assets known today is the replacement of compression systems, with each costing in the region of £40m.
The work undertaken in the Discovery phase has shown that repurposing of compression equipment is feasible. The project has so far concluded that it is feasible to repurpose an existing Avon Gas Turbine to enable the turbine to be fuelled with 100% hydrogen. Implementing hydrogen as a fuel gas for gas turbines on the NTS would eliminate the 165,000 kg of carbon dioxide emissions which are released at compressor stations annually.
The use of hydrogen as a fuel gas for gas turbines however will increase the amount of nitrogen oxides produced. The equipment to remove, reduce or capture these emissions has been utilized previously but must be
considered in the end-to-end cost of this activity.
Initial analysis undertaken on the existing compressor unit suggests that the compressor may be able to compress blends of up to 50% hydrogen, with modification, if a drop in the pressure ratio achieved can be accepted. Beyond this 50% blend, more inbuilt stages of compression would be required. Further work on the costs of modifications versus new hydrogen ready compressors and consideration of the blend point where it becomes more cost effective to replace the system will be determined in Alpha.
The ancillary equipment has also been considered during the Discovery phase. Systems such as fire and gas detection, fire suppression and ventilation will require modification for use with hydrogen and hydrogen blends; however, it is thought that components such as air intake and the exhaust can be re-used with hydrogen. A more detailed assessment will be carried out in the Alpha phase and a cost comparison undertaken.
Determining the most cost-effective route to compression is vital to keep costs to a minimum for energy consumers. Implementing hydrogen compression on the future energy network will enable hydrogen to be produced and transported where required and storage of hydrogen within the NTS (linepack), providing resilience to the network.
There have been no changes to the project since application and no changes to the impact of the project since the application stage.
