Research & Development
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From natural gas to hydrogen
NGT has executed studies on the suitability of our infrastructure for hydrogen transport. A first study – conducted by DNV-GL –researched if our pipelines, initially designed for the transportation of natural gas, can be repurposed to transport hydrogen.
The first study identified no showstoppers prohibiting hydrogen transportation. Recommendations were made for a follow-up workscope. Interesting is that our offshore pipelines are very similar to many of the Gasunie onshore pipelines, which Gasunie plans to reuse for the HyWay 27 hydrogen backbone.
No showstoppers prohibiting hydrogen transportation.
Fit for Use - Certification
NGT is currently performing a follow-up study – conducted by Bureau Veritas –investigating the requirements for transportation of hydrogen in more detail. This should result in a ‘fit for purpose’ status and eventually a hydrogen certification. NGT aims to acquire certified hydrogen suitability approval for safe and reliable hydrogen transportation both ad-mixed and pure form. This allows NGT to accommodate and support various offshore green hydrogen production initiatives via electrolysis.
The certification process will also enable a more accurate estimate of the costs associated with the modifications and the measures required to transport hydrogen, either admixed or pure. It is expected that the cost of reuse is an order of magnitude lower than installing new pipelines: reuse is only 10% of the cost of a new infrastructure.
Admixing versus pure hydrogen transport
NGT sees benefits in both pure and admixed hydrogen transport. The admixed phase may precede a pure H2 phase. At lower percentages, admixed hydrogen may stay in the gas stream. In our surrounding countries, trials with concentrations up to 20% are planned or executed. The EU has proposed that member states allow 5% hydrogen in the gas network at the border crossings. At lower percentages the hydrogen may not cause too much problems for existing natural gas users and would reduce the CO2 emission per m3 of hydrogen enriched natural gas. Further research is required to determine exactly which measures would need to be taken by households and industry. Higher H2 concentrations could be accepted in case the gas stream would be directed to one or more dedicated industrial sites which would be set up properly to handle these concentrations. The variability of H2 concentration in time (related to the wind profile) of the stream in this case is also a factor to consider.
Other methods towards a hydrogen supply
NGT is also investigating the feasibility of splitting a mixed 'hydrogen - natural gas' stream into a separate stream, so removing the hydrogen. NGT has engaged TNO to perform a study looking at various technologies, including membrane separation, cryogenic separation and pressure swing adsorption.
An alternative to separation is the conversion of natural gas in blue hydrogen. Doing so would result in a mix of blue and green hydrogen, which again can be fed into the hydrogen backbone. The remaining CO2 can then be transported and injected into empty gas reservoirs (CCS). Neptune Energy is performing a study to look at the injection into the L10 block, where also the NGT riser and compressor platform are located.
The most widely used technology is Steam Methane Reforming (SMR). An alternative technology is Autothermal Reduction (ATR). This technique requires oxygen that could come from an onshore electrolyser plant. A technology being developed is pyrolysis which is now being tested on a larger scale in the US. This process yield pure carbon rather than CO2, which can be stored or reused.
Transition from natural gas transport to hydrogen transport
Eventually our pipelines will no longer transport gas, either because the gasfields are 'empty', or rather the production rates are so low that they are no longer viable. Or the production may be stopped if the gas volumes are no longer required and sufficient alternatives are available. However (hopefully) the demand for hydrogen will develop rapidly as wind farms further offshore are developed for hydrogen. NGT may still have some gas customers, and admixing may not be the preferred solution. In this case NGT can relatively easily reroute the remaining gas field(s) to one of the other offshore pipleline systems.