Gas companies have highlighted possible low-emissions replacements for gas, and yet these are more costly, less certain, and less future-proof than electrification.
Proposals for gas replacements include methane made from organic waste (biomethane), or hydrogen produced with renewable electricity, referred to as green hydrogen. There are possible uses and benefits for these gases in certain hard-to-abate sectors, for example in industrial processes like steel production. There are also a lot of existing uses for hydrogen that is generated from natural gas, so we should use green hydrogen to replace that first. However, at the household level they are significantly more costly and less ready than direct electrification.
Biogas generally refers to methane produced by the fermentation of organic matter. It is ‘renewable’ since it is produced from organic sources like food waste and agricultural waste that will always be generated in perpetuity. Methane is a powerful greenhouse gas, capable of heating the planet by up to 100 times more than carbon dioxide in the short term. By capturing and using this methane (which is inevitably created from decaying organic matter), this method can prevent these emissions from escaping to the atmosphere and exploit their potential to provide energy.
Despite its benefits and potential role in a future energy mix, biogas is not a practical alternative to electrification and energy efficiency. Capacity to scale up biogas is limited and will take significantly longer than the simple deployment of existing efficient electric appliances and renewables; there is simply not enough feedstock to generate the quantity of biogas required to replace our current usage of gas.
Likewise, ‘electrolytic green hydrogen’ is an emerging technology that is likely to have a role in industrial production. There have been many suggestions as to how hydrogen can be produced. This includes an electrochemical process where hydrogen is separated from the source fuel. In this case, the carbon emissions would have to be captured and permanently contained. Other processes include electrolysis, which involves splitting water into oxygen and hydrogen.
At the household level the cost and effort to distribute renewables-generated green hydrogen far exceeds those of direct electrification. In practice, the renewable generation and pipelines required to produce green hydrogen for household use as a gas could more simply be used to directly electrify homes. Modelling has shown that hydrogen-only scenarios will require twice the electricity generation and have higher costs than hybrid supply options of gas and direct electrification. Recent international research found that a green hydrogen heating system would be roughly ‘two to three times more expensive’ than one relying on electric heat pumps in both the EU and UK.
Hydrogen: where is low-carbon fuel most useful for decarbonisation?
