If hydrogen is the answer to energy security, let's talk carbon, not colour

The simplest and most abundant element in the universe is increasingly seen as holding the key to tackling Earth’s most challenging problem – climate change. It’s an oft-repeated joke that ‘hydrogen is the fuel of the future, and always will be’, but its time really has come at last. Soon we will see hydrogen working alongside other green technologies – cutting carbon emissions and helping to achieve net zero.

Hydrogen can help decarbonise activities that electrification cannot. Think shipping, HGV trucks and buses and industrial processes that need very high temperatures, such as steelmaking. We cannot reach net zero without it.

Technological advances in this field are everywhere. Johnson Matthey’s HyCOgen^TM process, for example, uses clean hydrogen and atmospheric or waste CO₂ to produce syngas, which can be upgraded into sustainable aviation fuel, for example, and dropped into existing supplies.

As a fuel, hydrogen leaves behind only water, and none of the CO₂ or pollutants that are associated with fossil fuels. But before we can really declare this to be a clean-energy vector, we need to consider the carbon footprint associated with its production, and it’s here that things start to get complicated.

Front runners

Right now, most hydrogen is made by reforming natural gas – a process that creates so-called ‘grey hydrogen’. But this process also yields CO₂, making it ripe for replacement. 

We will rely on two technologies in the future: the first is ‘blue hydrogen’ – created in the same way as grey, but with the troublesome CO₂ captured and stored. Second, there is green hydrogen, produced by the electrolysis of water using electricity from renewable sources, such as wind or solar. There's a rainbow of other colours too, including pink (nuclear), turquoise (methane pyrolysis) and even white (naturally occurring and mined from rock). 

However, I believe the hydrogen colour-naming convention doesn’t tell the full story behind hydrogen production and this practice has now run its course. It has been an engaging and memorable way to classify what is, ironically, a colourless gas, but what’s needed now is a more nuanced approach to hydrogen nomenclature.

Let's talk carbon

It’s more appropriate to talk about the carbon intensity of hydrogen, rather than just declare one colour to be environmentally better than another. The ease of the colour-naming convention tends to invite overly simplistic comparisons of hydrogen production routes. For instance, it’s common to see arguments favouring green hydrogen (electrolysis from renewable electricity) over blue hydrogen (natural gas + CCS) because the blue variant still produces CO₂, and dealing with this is both expensive and has a carbon footprint all of its own.  

However, this argument fails to acknowledge the ease with which existing grey hydrogen plants can be retrofitted with CCS to make them blue – a process that has a much smaller carbon footprint than building a green hydrogen plant from scratch. For instance, JM’s suite of CLEANPACE^TM technologies enables the revamp of steam methane reformers with existing, proven technology to achieve CO₂ emission reductions of up to 95%. Such retrofitted blue-hydrogen plants have an important role to play; expanding the hydrogen market in which new blue hydrogen plants, and green hydrogen electrolysis facilities, can then thrive.

The colour naming convention also fails to take into account the technology variations within these categories. As analysis by the Hydrogen Council shows, the greenhouse gas emissions associated with green hydrogen production depend on how the electricity was generated. 

Similarly, a blue hydrogen analysis by UK government department BEIS highlights the impact of the reforming method on lifecycle emissions, with autothermal reformers (ATR) being more efficient and more compatible with CCS than steam methane reforming (SMR). Though, it's also worth noting that half of the hydrogen produced through SMR actually comes from the water used, not the methane. At JM, our own LCH^TM technology captures more than 95% of associated CO₂ emissions, and has best-in-class environmental credentials for ATR blue hydrogen production.

Blue hydrogen is often looked on as an intermediate technology – something to tide us over until green hydrogen electrolysis plants are ready to take over. We don’t see things this way. 

Complementary solutions

Rather than two opponents – one in the blue corner, the other in the green corner, slugging it out for supremacy – we see blue hydrogen and green hydrogen as being pieces of the same jigsaw. In the future, we’ll need both methods, working together to diversify supply and boost energy security. Diversity is important to insulate the market from price fluctuations. Both of these hydrogen generation methods have dependencies: CCS network capacity and natural gas prices in the case of blue hydrogen; and the availability and price of low carbon electricity for green.

Other factors to consider are speed and scale: blue hydrogen is ready to go now; green hydrogen will need until about 2030. At JM we believe every molecule of CO₂ entering the atmosphere is a problem – and something that blue hydrogen can help prevent in the short and medium term. Blue hydrogen’s potential to ‘move the needle’ quickly can be seen in the HyNet clean hydrogen project in the north of England, which has adopted JM’s LCH technology. When this comes on-stream in 2025, production capacity will be 3 TWh, with the potential to scale to 30 TWh by 2030. In contrast, Shell Rotterdam – reported to be Europe’s biggest renewable electrolytic hydrogen production facility, will produce about 1 TWh when it comes onstream in 2025. 

The suitability of hydrogen production methods will also change according to location. Newly built blue hydrogen plants will often be more attractive to countries that have reserves of natural gas and the geological formations to deal with the captured CO₂. The HyNet project in the UK is a great example. 

On the other hand, green hydrogen will suit territories that have an abundance of renewable electricity. For example, in NEOM – Saudi Arabia’s futuristic city under construction – the country’s bountiful solar and wind resources will help produce 1.2 million tonnes of green hydrogen every year by 2026. And in California, approximately 1TW of solar electricity is wasted every year, because an outdated electricity grid can’t take it. That’s an amount of energy equivalent to four nuclear reactors, all of which could be stored in the form of green hydrogen – or converted into a high-density energy carrier such as ammonia.

Language matters

For us to move away from colours and concentrate on carbon footprint, we’ll need to change our language around hydrogen. Defining and implementing proper low carbon hydrogen standards is essential if all stakeholders are to know what ‘clean hydrogen’ actually means. Grouping hydrogen production by carbon intensity – not colour – as the US has proposed in its Inflation Reduction act, gives clarity and freedom to project developers when choosing technology and seeking funding.

To achieve a low carbon hydrogen economy, we are calling for technologically agnostic standards to be adopted as soon as possible. These should be global, or at least be regionally aligned, to facilitate a worldwide market for clean hydrogen – something that would blur the distinction between colours even more. But where there are standards there also needs to be regulation, and there are important questions that need to be addressed here. Implementation and adoption are key but who will regulate, incentivise and direct the use of these standards? Will it be left to national governments, or an international agency?

Numerous low carbon hydrogen standards are already in development. While we are happy to work within any framework, we want to see the inclusion of upstream emissions (such as fugitive methane emissions and escaping CO₂). To this end, the most sensible approach seems to be a standard that covers well-to-gate emissions associated with hydrogen production.

Having a global infrastructure standard for pipe and fittings would also help lower hydrogen proliferation costs.

The Hydrogen Council estimates that 18% of all our energy will be made from hydrogen sources every year by 2050. Just as there’s no magic bullet for providing the world’s green energy needs, so there is no one-size-fits-all approach to clean hydrogen production. We need a diverse network of suppliers around the world, each using the right method for them. 

Our language – and our preconceptions about existing technologies – must change and new ways of measuring carbon intensity must be found. It’s an incredibly exciting time to be involved with hydrogen – and at JM we’re proud to be at the heart of it

This article was originally published in the November 2022 issue of Decarbonising Technology