Question 1

Can hydrogen be added to the gas grid?

Accepted Answer

Hydrogen can be added to the gas grid in a limited share, which depends on gas quality, pipe materials, customers and regulations, so permissible concentrations are set individually.

Hydrogen has different properties from methane (lower energy density by volume, wider flammability limits), which affects gas appliances and storage. For this reason operators study the limitations. For a biogas plant this means that hydrogen from local processes is more likely to be used on site or converted into methane (biological methanation) than injected directly.

Sources: Renewable hydrogen — Komisja Europejska

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Question 2

Does the agreement with Hyphen mean construction has started?

Accepted Answer

No. The Feasibility and Implementation Agreement sets the legal framework and the design stage. Construction still requires an execution contract and financing of the investment.

Question 3

Does the roadmap say anything about biogas?

Accepted Answer

Its main subject is vehicles, stations and fuel cells, and the hydrogen supply chain. Biogas appears rather in separate policies on organic waste – see the entries on the Korean biogas act.

Question 4

How does photofermentation differ from dark fermentation?

Accepted Answer

Photofermentation requires light and photosynthetic bacteria, which convert organic acids into hydrogen, whereas dark fermentation takes place without light and breaks down sugars.

The two methods can be combined in a two-stage system: in dark fermentation sugars are converted into acids and hydrogen, and photofermentation uses these acids for additional hydrogen production. This requires transparent reactors and control of light and temperature, which increases costs and complexity. These technologies remain mainly at the research stage.

Sources: Synergies of flexible bioenergy with green hydrogen and negative emissions — IEA Bioenergy

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Question 5

How should promises about a new biohydrogen technology be assessed?

Accepted Answer

Promises should be assessed by the scale of demonstration, measurable results (H₂ yield, purity, continuous operating time), the full energy and emissions balance, and costs compared with alternatives.

It is worth asking: do the data come from a laboratory reactor, a pilot or a commercial plant? How long did the process run? What are the energy consumption, losses and by-products? Was the result repeated independently? Results under ideal conditions rarely translate to industrial scale. The lack of independent verification is a signal for caution.

Sources: Synergies of flexible bioenergy with green hydrogen and negative emissions — IEA Bioenergy

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Question 6

Is biohydrogen already a commercial technology?

Accepted Answer

Most methods of biological biohydrogen production (dark fermentation, photofermentation, MEC – microbial electrolysis cells) are not yet commercial technology, whereas biomethane reforming is a known solution, although rarely used in this application.

Biological technologies have low yields, and scaling up is costly. International reports point to biohydrogen as a potential element of the bioenergy system, but without guarantees of profitability. An investor should treat these solutions as risky and requiring funding for research or demonstration.

Sources: Synergies of flexible bioenergy with green hydrogen and negative emissions — IEA Bioenergy

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Question 7

Is biomethane an RFNBO?

Accepted Answer

No. RFNBO are fuels made from renewable hydrogen not produced from biomass, and from CO₂ or nitrogen. Biomethane is made from biomass, so it is a biofuel; it can, however, supply biogenic CO₂ for the production of e-methane.

Question 8

Is FH2R biohydrogen?

Accepted Answer

Not in the biological sense: it is hydrogen from water electrolysis powered by renewable energy. The entry is placed in the hydrogen category because it shows how Japan is building a hydrogen value chain, including hydrogen that may in future be supplemented with hydrogen from biogas.

Question 9

Is hydrogen from biomethane produced without CO₂ emissions?

Accepted Answer

No, reforming of biomethane (SMR) emits CO₂, but it is CO₂ of biogenic origin, so the climate balance can be favourable, especially if the CO₂ is captured and stored.

Steam methane reforming produces hydrogen and carbon dioxide. When the feedstock is biomethane, the CO₂ emission is offset by earlier uptake by plants, provided the whole chain is sustainable. Adding CO₂ capture (BECCS) can give negative emissions. The assessment requires a life cycle analysis, taking methane losses into account.

Sources: Synergies of flexible bioenergy with green hydrogen and negative emissions — IEA Bioenergy; Renewable hydrogen — Komisja Europejska

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Question 10

Is hydrogen in an MEC produced without electricity?

Accepted Answer

No, in microbial electrolysis cells (MEC) microorganisms break down organic matter, but an additional, small electrical voltage is needed to obtain hydrogen.

MEC technology is low-energy compared with classic water electrolysis, but it requires external energy and complicated reactors. It remains at the laboratory and pilot research stage. Efficiency depends on electrode materials, wastewater composition and biofilm stability, and scaling up is a challenge. For this reason MEC is today treated as a research direction, not a ready solution for biogas plants.

Sources: Synergies of flexible bioenergy with green hydrogen and negative emissions — IEA Bioenergy

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Question 11

Is the hydrogen in Egypt's strategy "biohydrogen"?

Accepted Answer

No. The strategy mainly concerns low-carbon hydrogen (green from electrolysis and blue), not hydrogen from biomass or biogas.

Question 12

Is hydrogen produced from biogas an RFNBO?

Accepted Answer

No, hydrogen produced from biomass or biogas is not an RFNBO, because this category covers renewable fuels of non-biological origin (e.g. hydrogen from electrolysis powered by renewable energy sources).

Hydrogen from biogas is subject to the rules for fuels from biomass and the sustainability criteria. RFNBOs are fuels whose energy comes from renewable sources other than biomass. The distinction matters for certification, transport targets and support schemes, because the two pathways have separate rules.

Sources: Renewable hydrogen — Komisja Europejska

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Question 13

What do the colours of hydrogen (green, blue, grey) mean?

Accepted Answer

The colours of hydrogen are an informal classification by production method: green — from electrolysis using renewable energy sources, grey — from natural gas without CO₂ capture, blue — from natural gas with CO₂ capture.

Biohydrogen has no single colour in this classification; it is sometimes called "green" or "biogenic", but EU law uses categories (renewable, low-carbon hydrogen) with precise emission criteria. Colours are a marketing shorthand, so investment decisions should be based on formal definitions.

Sources: Renewable hydrogen — Komisja Europejska

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Question 14

What is biohydrogen and how is it produced?

Accepted Answer

Biohydrogen is hydrogen produced from biomass or organic waste by biological methods (e.g. dark fermentation, photofermentation) or by reforming biogas and biomethane.

The name covers various technologies of differing maturity. Dark fermentation and photofermentation are mainly at the research and demonstration stage, while methane reforming from biogas is based on technology known from natural gas, fed with biomethane. The climate assessment depends on the source of the feedstock, the energy of the process and the handling of CO₂. Not every technology is commercially ready.

Sources: Synergies of flexible bioenergy with green hydrogen and negative emissions — IEA Bioenergy

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Question 15

What is biological methanation?

Accepted Answer

Biological methanation is a process in which archaea use hydrogen and CO₂ to produce methane, which makes it possible to convert surplus electricity (hydrogen from electrolysis) and CO₂ from biogas into biomethane.

Hydrogen is introduced into the digester or a separate reactor, where hydrogenotrophic methanogens convert the CO₂ present in the biogas into additional CH₄. This increases the methane yield from a given amount of substrate. The technology is being tested in pilot plants and requires access to cheap hydrogen and control of pH, which rises as CO₂ is consumed.

Sources: Synergies of flexible bioenergy with green hydrogen and negative emissions — IEA Bioenergy

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Question 16

What is dark fermentation?

Accepted Answer

Dark fermentation is the anaerobic breakdown of carbohydrates by bacteria without the involvement of light, whose products are hydrogen, CO₂ and organic acids (e.g. acetic and butyric).

So that the hydrogen is not consumed by methanogens, the process is run under conditions that inhibit them (low pH, short retention time, heat treatment of the inoculum). Theoretically a maximum of 4 moles of H₂ can be obtained from 1 mole of glucose (the acetate pathway), but in practice markedly less is achieved. The remaining acids can be processed further in methane fermentation or photofermentation.

Sources: Synergies of flexible bioenergy with green hydrogen and negative emissions — IEA Bioenergy

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Question 17

What is "Offre Maroc"?

Accepted Answer

It is Morocco's national offer for investors in green hydrogen and its derivatives, including the provision of public land (up to 30,000 ha per project) and a framework for cooperation with the state. The government refers to the king's vision and the Throne Speech of July 2023.

Question 18

What is the Hydrogen Valley in South Africa?

Accepted Answer

It is the concept of a hydrogen corridor from the area around Mokopane in Limpopo through Johannesburg to Durban. The project is one of the catalytic projects in the roadmap.

Question 19

Why is a hydrogen stage combined with methane fermentation?

Accepted Answer

Combining a hydrogen stage with a methane stage makes it possible to produce hydrogen from the readily degradable fraction and convert the remaining products (acids) into methane, increasing the overall use of the substrate's energy.

In a two-stage system the first reactor operates at low pH and a short retention time (H₂ production), and the second — under conditions typical for methanogenesis. This improves stability and kinetics, because each stage works at a different optimum. The drawbacks are the cost of the additional reactor and the complexity of control. The technology is used mainly at research and pilot scale.

Sources: Synergies of flexible bioenergy with green hydrogen and negative emissions — IEA Bioenergy

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