Earth Day Series Day 20: Hydrogen. Beyond Tomorrow.

April 20, 2021

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by Gaulthier Blangez* (Advanced Biofuels USA) Let’s go back to the basics. The “Bio” term comes from ancient Greek and is translated as “Life.” Widely used in our day to day vocabulary, this term has found its place in our language by becoming a prefix.

Biochemistry studies chemical reactions happening inside living organisms, biology studies these living organisms; by extension biofuels are fuels produced with natural and non-fossil resources. In addition, they are qualified as “advanced” when the so-called resources aren’t food crops.

For years now, a resource shift has started. While oil was the necessary resource to produce the fuel used during the beginning of the last century, we have today a wide choice of products that can be converted into fuels, products regenerating faster than oil, products that were wastes before. All of them come from biomass, either unused (crops, algae, wood) or as leftovers or waste (used cooking oil, animal fat, wood residues).

Nevertheless, if it seems that we pushed the fuel paradigm to its climax, technology proves us wrong. If tomorrow renewable fuels will get their spot under the sun, they might evolve once more to free themselves from biological resources dependency. To understand how it is possible let’s dig deeper.

Non "Bio" Renewable Fuels

To produce renewable fuels, many pathways are to be considered. Among them all, the Fischer-Tropsch pathway is the one we want to focus on: it exploits a chemical synthesis to convert syngas (carbon monoxide and hydrogen) into hydrocarbons.

Usually, producing renewable fuels this way means to gasify the feedstock to get the carbon monoxide and some hydrogen while the additional required supply of hydrogen comes from an electrolysis process requiring electricity to transform water (H2O) to hydrogen (H2) and oxygen (O). To sum up, taking such pathways requires carbon monoxide from biomass, water and electricity.

Well, here’s something that could lead us to what could be the future of renewable fuels. It is technologically possible to convert carbon dioxide into carbon monoxide. So, what if instead of using biomass, we used thin air. Or more specifically, the CO2 in it. Given the availability of raw CO2, which is unlimited, this technology might solve the feedstock issues capping biofuels production volumes. How would it technically work ?

What is critical about such a production scheme ?

If we had to sum it up. Two elements make such a production scheme complicated to adopt in 2021.

First, the technological availability, for two reasons. On one hand you have the Fischer-Tropsch synthesis that isn’t ready yet for commercial development. In fact, the first pre-commercial unit has just been completed in France, by Axens, through their “BioTFuel” program. Therefore it’s not possible, at the moment, to start a commercial unit based on the Fischer-Tropsch synthesis.

On the other hand, the direct air carbon capture machinery also isn’t ready as well to be exploited on such a large scale. Companies like Carbon Engineering or Climeworks are developing adapted equipment that would fit in an industrial scale production unit but the commercialization step isn’t reached yet. For more information about such equipment, I invite you to refer to the orca project from Climeworks.

Second, the hydrogen. As we’ve seen, it comes from a chemical process requiring both water and electricity. Well, let’s focus here on the electricity because of a debate that is roaring backstage: let me introduce you to a colorful world.

Depending on the electricity and feedstock source, hydrogen is more or less clean. It goes without saying that it is definitely preferable to get it from renewable electricity than from coal, environmentally speaking.

Therefore a typology has been created to categorize hydrogens depending on the source of the hydrogen how it has been produced.

Brown/Black hydrogen: made from coal--brown (lignite) or black (bituminous) coal
Grey hydrogen : made from fossil natural gas
Turquoise hydrogen : byproduct of methane production
Pink hydrogen : made with nuclear electricity
Green hydrogen : made with renewable electricity, water, biomass gasification or biogas
Blue hydrogen : made from fossil natural gas when paired with carbon capture and storage
White hydrogen : naturally formed
Yellow hydrogen : made from mixed sources of electricity

As you know, when it’s about renewable biofuels, development plans are made to be as sustainable as possible.

Therefore you’ll mostly hear about green and blue hydrogen in the context of renewable fuels production. These kinds of molecules are from two to four times more expensive than the grey kind. The main price reduction vector is represented by a scale effect on the renewable electricity production that would reduce the price of green hydrogen. Furthermore, to get hydrogen at a cheaper price, pink hydrogen slowly starts to be considered.

What You Can Do

Learn more about hydrogen as a fuel. You can find more information here: https://advancedbiofuelsusa.info/tag/hydrogen-renewable-hydrogen/

Learn more about hydrogen and carbon dioxide as a way to make renewable fuels or electrofuels/e-fuels. You can find more information here: https://advancedbiofuelsusa.info/tag/electrofuels/

Find more Earth Day 2021 posts here.

Join us for Introduction to Renewable Fuels: What, How and Why? — April 28, 2021 — ONLINE

*Gaulthier Blangez has a Masters degree in Energy and Environment Economics from the French Institute of Petroleum and New Energies. He looks forward to a career managing sustainable aviation fuel (SAF) projects and is working on a white paper summarizing pathways to SAF for Advanced Biofuels USA.

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