Converting natural gas to hydrogen can only be considered low-carbon when a very high proportion of the CO2 is captured and stored and when the emissions from natural gas production and leakage are small.  If these conditions are met, hydrogen from SMR with CCS can be a low carbon energy carrier and thus be a tool for reducing emissions in some hard-to-abate sectors. When the emitted CO2 is captured and permanently stored, the hydrogen has a smaller carbon footprint than its fossil equivalent and can be used as a heat source for industry or as a feedstock for chemicals.

Provided that upstream emissions of the natural gas supply chain are low and most of the CO2 from the SMR process is permanently stored, hydrogen from SMR+CCS can achieve significant emission reductions [x], especially in industrial applications. When used in the direct reduction ironmaking process, low-carbon hydrogen has a >80% emission abatement potential compared to BF-BOF steel production [2], by emitting around 0.4 tCO2 per tonne of crude steel. However, fugitive greenhouse gas emissions from the extraction of fossil fuels also need to be factored into that calculation [xi]; if these emissions are too high, the potential emission reduction is significantly lower [3]. Overall, hydrogen from renewable electricity has a higher mitigation potential of >95%. 

The addition of CCS to the hydrogen process results in a 5-14% reduction in efficiency levels, so finding applications where the hydrogen gas can be directly used can help to avoid further efficiency losses. In order to calculate and ensure climate benefits, all emissions in the SMR+CCS including possible methane leakage should be accounted for [xii].

Even though hydrogen made from natural gas with CCS is not zero carbon, it could help lower emissions in energy intensive industries. By encouraging larger infrastructural investments and penalising the use of unabated natural gas, hydrogen from SMR+CCS can also provide a push for the more rapid roll-out of electrolysis hydrogen and low-cost renewable electricity on a larger scale.

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[2] BF-BOF stands for ‘blast furnace-basic oxygen furnace’ steel production and is the most common way of producing new steel.

[3] To avoid high life cycle emissions, fracking and shale gas operations and gas systems with a high rate of leakage should be excluded from the production of SMR + CCS hydrogen.

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