Benefits of hydrogen blending in gas networks highly variable, study finds
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Efforts to lower carbon emissions from gas networks by replacing some of the gas with hydrogen could see higher bills for consumers, a study has found.
Fraunhofer IEE has assessed the technical feasibility, emission savings and cost impacts from plans to add hydrogen to the existing gas transport network.
The process, known as 'hydrogen blending', is currently being discussed by the EU as a way to lower carbon emissions from gas networks across its member states.
But the study found that the carbon benefits of such a practice are highly variable depending on the type of hydrogen used and believes that other industries may be more suited to using the fuel.
Furthermore, the measures for hydrogen blending are currently estimated to increase costs for end users by up to 43 per cent for industry and up to 16 per cent for households at a blending level of 20 per cent of the total gas volume.
Hydrogen production is typically delineated into 'green' methods, which can be carbon neutral through the use of electrolysis to separate it from water, and blue hydrogen, which is not carbon neutral as it is produced by splitting natural gas.
Blue hydrogen can only be described as a net-zero carbon fuel when used in conjunction with carbon capture and storage; furthermore, studies have found that blue hydrogen is more carbon-intensive as a source of heat than natural gas, coal, or diesel.
The EU currently plans to have the capacity to create green hydrogen with an energy generation potential of 40GW by 2030. But while substantial quantities of hydrogen could be absorbed by the gas networks at relatively low degrees of blending, it would also force it to compete with other large hydrogen demands in the industry and transport sector.
“In view of the limited amounts of green hydrogen that will be available in 2030, it is important that these should find concrete applications with high CO2 reduction potential, instead of being 'poured as if with a watering can' into the natural gas network where it will offer limited CO2 reduction,” the Fraunhofer study said.
Britain’s gas grid is currently being prepared to accept a blend of up to 20 per cent hydrogen from next year as part of decarbonisation efforts.
But the study found that even this relatively high level of substitution would correspond to only 6-7 per cent greenhouse gas savings due to the lower heating value of hydrogen compared to natural gas.
“In the medium-term, the limiting factor is the availability of green hydrogen – which means that additional renewable energy capacity has to be built to cover the hydrogen production,” the study said.
“Direct green H2 use has clear advantages for achieving the 2030 climate targets. However, investment decisions must take long-term efficiency into account.
“The creditability of the limited amount of green H2 in the respective sectors in 2030 must also take this long-term use into account. Building an infrastructure for blue hydrogen would also take time. Furthermore, blue hydrogen is not CO2-neutral in particular due to the associated methane emissions. Apart from this, it would be available only in limited quantities at an early stage of development and should therefore not be treated as equal to green hydrogen.”
Instead the study recommends using it in sectors where there are currently few alternatives for decarbonisation such as steel production or other industrial applications, and shipping and aviation fuels.
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