18.01.22 If both of them are climate-friendly, then let’s use both! Interview with Christian Bauer • Reading time: 4 min.

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Zusammenfassung

How climate friendly is blue hydrogen? This question is currently the subject of heated debate. Christian Bauer from the Paul Scherrer Institute in Villigen in Switzerland has carried out a study together with other researchers to investigate this question. In this interview, he explains why the trench warfare over blue hydrogen needs to stop.

Christian Bauer from the Paul Scherrer Institute in Villigen in Switzerland

Blue hydrogen is regarded as a transition technology that we will use until enough green hydrogen is available. When do you think green hydrogen will be produced in large quantities?

That's difficult to say. To achieve the EU targets for green hydrogen, we would need a huge expansion in renewable energy generation and electrolysis capacity. The expansion rate would have to be much higher than it has been in the past in the photovoltaic sector. Although this is possible, it represents a very big challenge.

The use of blue hydrogen is the subject of heated debate. Where do you think the problems lie?

Blue hydrogen must be used to protect the climate, but this requirement will only be met if emissions of harmful methane from the production and transport of natural gas are kept to an absolute minimum and if almost all the carbon dioxide is separated out during the process of reforming natural gas. The separation of the carbon dioxide is possible using modern plants, but the picture is more mixed when it comes to the extraction and transport of natural gas, with both good and bad examples. On a global scale, the methane losses vary between 0.1 and eight percent of the total natural gas. These are, of course, enormous differences and this is what determines whether or not blue hydrogen is climate friendly.

A study carried out in the USA has come to the conclusion that blue hydrogen cannot help to protect the climate. Why does your study take a different view?

This US study was the trigger for our own investigation. In my opinion, it takes a very one-sided approach and focuses on the worst possible assumptions, which means that its results only apply under certain conditions and do not paint a representative picture of blue hydrogen. We wanted to show the realistic assumptions that would allow blue hydrogen to play a role in protecting the climate. And with modern plants that is absolutely possible.

What approach did your study take?

We relied primarily on methane emission figures from the International Energy Agency (IEA) and from studies carried out in the USA. We identified major regional differences. For example, in Norway and the United Kingdom methane emissions are particularly low, while the figures in the USA vary significantly. The highest methane emissions of up to eight percent are found in Libya and Iraq. The US study took its figures for natural gas reforming from plants that separate CO2 for use in oil extraction. But in this process, high CO2 separation rates are completely unimportant. Technologies are already available that can separate almost all the carbon dioxide and I think that these will be used in the years to come.

Assuming that blue hydrogen is produced under ideal conditions, how high would the levels of CO 2 emissions be in comparison with green hydrogen?

A legitimate comparison would show that the carbon footprint of blue hydrogen in this case would be roughly the same as that of green hydrogen produced using solar energy. This is because the manufacturing process for photovoltaic modules is also energy-intensive and therefore involves CO2 emissions. But I don’t believe in playing blue and green hydrogen off against one another. If both of them are climate-friendly, then let’s use both!

How expensive is blue hydrogen?

At the moment, we mainly use grey hydrogen, which is produced from natural gas without separating the carbon dioxide. Blue hydrogen is around 50 percent more expensive than this at present. But I think that in the next few years the difference in the prices will reduce. The cost of green hydrogen, which is currently much more expensive, will also fall. And we need to keep an eye on the prices of CO2 certificates. If they rise significantly, green and blue hydrogen will become competitive more quickly.

In conclusion, I'd like to ask you to sum up your view of the controversy surrounding green and blue hydrogen.

I would like to highlight two points. Firstly, with any type of regulations, we need to consider the entire value chain, in other words, greenhouse gas emissions from the extraction of natural gas, the production of hydrogen, and also the generation of electricity from renewable sources. In other words, regulations should be based on the complete carbon footprint. Otherwise we are in danger of making the figures look better than they actually are and laying ourselves open to attack. As I have already said, we should not be playing blue and green hydrogen off against one another. I find this trench warfare mildly amusing. Who cares about the color of the hydrogen if it has been shown to produce very low CO2 emissions? The only important consideration is that enough is available.

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