Hydrogen is derived from the Greek 'hydro' and 'genes' meaning ‘water creator’. When burned it reacts with oxygen in the air to create water. It produces seven times as much energy as an equivalent quantity of coal and is the most abundant element in our universe. However, it’s not currently a mainstream source of energy.
Today around 94Mt of hydrogen is produced per year, generating around 900Mt of CO2 annually, more than the entire UK. In its current form, the hydrogen industry is a heavy polluter. As a highly reactive gas, hydrogen rarely exists in isolation and usually binds itself to other elements, such as carbon and oxygen, meaning additional energy is required to separate it from other compounds. There are many ways to do this, but not all methods are ‘green’ or low carbon.
The most common way to artificially produce hydrogen is through a process called steam-methane reforming, or ‘grey hydrogen’. This process generates carbon gas, none of which is captured, and it makes up 96% of the hydrogen industry. Carbon-based production using coal instead of methane produces similar results; however, this is a dirtier method and is known as black or brown hydrogen.
A lower-carbon alternative is blue hydrogen, which captures and stores the carbon produced in stream reforming. Blue hydrogen is sometimes referred to as carbon neutral; however, some argue that ‘low carbon’ is a more accurate description, as 10–20% of net carbon is released during the carbon capture and storage process.
Green hydrogen is a far cleaner option and is created through electrolysis using renewable energy sources, such as solar or wind power. It currently makes up about 1% of all hydrogen production but is expected to grow as the cost of renewable energy falls each year.
Around 3 in 4 UK households are connected to the gas grid. To reach net zero, the UK needs to reduce the average household’s annual carbon emissions from nearly 3 tonnes to just 135kg by 2050 – a drop of 95%. In 2021 the UK government published its Ten Point Plan for a Green Industrial Revolution, which included plans to create 5GW of low-carbon hydrogen by 2030 and steps to allow 20% of blue hydrogen to be blended into the grid for all homes by 2023 – this deadline has now been extended to 2025. This investment has been met with criticism, with many deeming it ‘techcrastination’.
Techcrastination is a term attributed to the investment in new technologies over existing, reliable and cost-effective options, essentially a waste of time and money. Investment in hydrogen technology is arguably an example of techcrastination, as decarbonising buildings with hydrogen technology is one of the least-efficient and most expensive methods currently available.
For example, the amount of renewable energy needed to produce green hydrogen to heat UK homes is 500–600% greater than the amount needed to power an equivalent number of heat pumps. As a result of this inefficiency, the required build rates for renewables would be extremely challenging – a fact the UK Committee on Climate Change points out in its review of the future of hydrogen.
Additionally, converting a gas grid into a hydrogen one is not as easy as simply funnelling a new gas through existing pipes. Hydrogen is a volatile gas which can degrade older pipes and leak in newer ones, but investment into rectifying and mitigating these risks undermines climate progress. As numerous studies have concluded, rapid electrification of buildings and retrofits to improve efficiency are critical this decade to meet the 2050 net zero target. Techcrastination around hydrogen is therefore a hindrance to progress, rather than a solution.
It’s unclear whether hydrogen is required to decarbonise our buildings by 2050, and there’s currently too much technological uncertainty to scale it up in time. While the UK government is currently focused on blue hydrogen and ‘hydrogen blending’ solutions, current infrastructure can only safely blend hydrogen with natural gas at a rate of up to 20%. It would therefore take additional time and resources to upscale these processes, and this could cause more delays in achieving net zero by 2050.
Net zero by 2050 is a deadline we can’t afford to miss, and while green hydrogen has a potential role to play in achieving this target, we must consider its use sensibly and cautiously to avoid unnecessary time wasting and costs. As architects, rather than feeding into techcrastination, we should focus on repurposing existing feasible options: all-electric, Passivhaus designs; prioritising sustainable, low-carbon materials; and designing more accessible, walkable towns and cities that ease transport emissions. We don’t need to force the use of hydrogen to decarbonise the built environment.