Beyond Green Hydrogen
Hydrogen colours are a handy shorthand but we should look closer.
February 6, 2023
By now, it’s almost impossible not to have heard of hydrogen colours – a key code of hydrogen hues that tell us about the energy source behind any given hydrogen gas.
The most important to know are green hydrogen, blue hydrogen and grey hydrogen, although there are more to learn about if you’d like to go deeper down the rabbit hole.
But there’s also an emerging understanding that within each colour — for example, the vital green hydrogen made from renewable energy and water — not everything is equal.
For example, what is the carbon intensity of green hydrogen produced by various parties with different electrolysers and varying energy sources?
And just as important: when people claim that blue hydrogen is a “low-carbon” hydrogen, how can we examine this to meaningfully compare its footprint against green hydrogen?
What is green?
Such questions are increasingly being examined around the world as work is done to set up national, regional and international green hydrogen standards, certifications and definitions.
Chief among them are the European Union’s Delegated Act defining “renewable hydrogen” as well as its emerging US counterpart, in addition to proposals for international standards from groups such as the Green Hydrogen Organisation and the International Partnership for Fuel Cells and Hydrogen in the Economy (IPHE).
Putting aside the potential issue of multiple competing standards, it’s important work.
Why? Take a theoretical example: One electrolyser produced locally using renewable energy is run entirely on excess solar power from nearby PV modules, while an imported one manufactured with fossil fuel electricity is run off power from the grid certified as renewable.
Although the latter may have a much higher carbon intensity, this is hard to see without standards that define the limits of embodied carbon allowed when calling hydrogen green, and the source of energy that can be used to make it.
The last point is important as analysts suggest an electrolyser producing hydrogen solely from grid electricity can have a much worse carbon footprint than grey hydrogen production.
How clean is “low-carbon” hydrogen?
That leads us to another question. Other names such as “low-carbon” or “clean” hydrogen are used in efforts to add blue hydrogen to the pantheon of decarbonisation solutions.
The names don’t give much information, so how much carbon are we talking about here since the source of this hydrogen is fossil fuels?
Blue hydrogen is produced mainly from natural gas using a process called steam reforming. The carbon dioxide resulting from this production technically can be caught and squirrelled away through Carbon Capture, Utilisation and Storage (CCUS) projects.
The problem is that even if CCUS targets the capture of 90-95% of emissions — and trials to date have sometimes struggled to even reach half of that — the best of blue hydrogen has a way higher carbon intensity than green H2 and thus, may not contribute to decarbonisation.
Hence many, including Enapter, don’t see it as a true climate solution, even in the interim. We need to look at the actual carbon footprint, not the hype, and set standards accordingly.
While we support the establishment of standards to address the above issues — and are in contact with those making them — our personal focus is making the best electrolysers possible while minimising their environmental impact.
We do this pursuing the aim of industrial production with zero negative impact: Life Cycle Impact Zero. While it isn’t just about CO2 emissions, this plays a huge and overlapping part.
For example, our new EL 4.0 electrolyser has been designed with recyclability in mind and ongoing optimisation ahead. This circular economy approach is aimed at cutting waste and greenhouse gas emissions by decreasing use of raw materials.
Our Enapter Campus production and R&D site in Saerbeck, Germany, will be 100% powered by locally-produced renewable energy – including rooftop solar.
We have quite some ideas about how we can continue to reduce the carbon intensity of the green H2 created using our AEM Electrolysers – and we’re already putting them into action.
And while the term “renewable hydrogen” may better reflect the need to only use renewable energy sources, we’ll also continue to use the term “green hydrogen” as it’s commonly understood shorthand to communicate the fact that only one form of H2 can be sustainable.
But it’s time for the discussion to evolve beyond colours to the true impact of hydrogen.