It would be better to reuse our existing natural gas infrastructure, for example, to transport hydrogen.

Unfortunately, existing natural gas infrastructure will, in many cases, not be suitable for use with hydrogen and the costs of converting this infrastructure may well exceed those of direct electrification.

It is natural human instinct to want to continue pushing projects into which one has invested time and money even after they cease to be the right choice. So common, in fact, that it has many names – such as the sunk cost or concord fallacy. However, the large investments made in natural gas infrastructure historically should not fool one into thinking that it must be the lowest cost option going forward.

The reality is that natural gas infrastructure is, in many cases, exactly that – natural gas infrastructure that cannot be used for hydrogen. Some of the most important challenges to appreciate in this regard are that the metal pipes used to transport natural gas cannot be safely used to transport hydrogen and that the natural gas appliances attached to the gas network cannot be used with hydrogen.

For the pipes, the key problem is so-called hydrogen embrittlement. Metal pipes tend to become susceptible to cracks when exposed to hydrogen and, consequently, the metal infrastructure used to transport natural gas cannot generally be used to safely transport hydrogen. For appliances, differences in the combustion characteristics of natural gas and hydrogen mean that, in many cases, consumers’ appliances would anyway need to be replaced or retrofitted. This is not only costly but poses a significant coordination and safety challenge, as retrofits must be coordinated with the changes to the network to ensure safe, continued service, potentially implying mass street-by-street refits.

Overall, therefore, it is important to realise that the existing natural gas network does not represent free hydrogen infrastructure and direct electrification will, in many cases, be cheaper than the use of hydrogen.

Reference:

Frazer-Nash Consultancy, “Appraisal of Domestic Hydrogen Appliances,” 2018, https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/699685/Hydrogen_Appliances-For_Publication-14-02-2018-PDF.pdf