The European Union’s (EU) aims to fully decarbonise its economy will require a complete overhaul of the energy system and its infrastructure by 2050. Since the announcement of the European Green Deal in 2019, a wide range of plans have been put forward to strengthen the region’s climate mitigation policies.

A decarbonised Europe will be jointly based on the production of renewable electricity and the deployment of green molecules to transport, store and supply all sectors with renewable energy at the lowest possible cost.

The plans to fully decarbonise the EU energy system, in conjunction with the current energy crisis, will change the demand for gas in the near future. Natural gas demand is expected to decrease to an estimated 271bn m³/y year by 2050, according to the Gas for Climate report.

By then, two major renewable gases will be capable of meeting this remaining gas demand: biomethane and green hydrogen. These sustainable gases could be used for almost all energy end-uses and could ensure security of supply.

However, green hydrogen produced via electrolysis using green electricity is still expensive and scarce today. Although it should become more readily available in the future, not all locations will have access to it at an acceptable price. Locally produced biohydrogen, a type of green hydrogen derived or produced from biogenic sources, could therefore have a clear role to play to accelerate the roll-out of green hydrogen in Europe.

Generating biohydrogen from domestically produced biogases would reduce the need to import gas and directly improve Europe’s energy independence and security. This helps to cushion against exposure to volatile natural gas prices.

The multiple shades of hydrogen 
Hydrogen can be produced using renewable or fossil energy. Each production pathway is categorised with a different colour according to the nature of the generation process: black comes from coal, grey and blue from natural gas, red and pink from nuclear.

In Europe, we produce mostly grey hydrogen today, which comes from natural gas without a greenhouse gases (GHG) capture process. Over 95% of European hydrogen production capacity comes from fossil fuels. Green hydrogen production routes are in the early stages of commercialisation and account for less than 1% of the total hydrogen production in the EU. Consequently, one of the main challenges of the hydrogen sector is to decarbonise its own production.

The best-known green hydrogen today is obtained via electrolysis of water using clean electricity from surplus renewable energy sources, such as solar or wind power. However, we can also produce it from biogenic sources, such as biogas (a mixture mainly of methane and CO₂). This type of green hydrogen is called biohydrogen, and could play a crucial role in speeding up the deployment of renewable hydrogen in the coming years.

Generating biohydrogen from domestically produced biogases would reduce the need to import gas and directly improve Europe’s energy independence and security. 
 

Think negative! 
The production of biohydrogen can be carbon negative when combined with a carbon sequestration process (CCS) or obtained from feedstocks such as waste and manure, and it requires low electricity needs. Hence, biohydrogen production has the unique ability of removing carbon from the atmosphere. The carbon footprint of biohydrogen ranges from –26.5 to 10.8 kg CO₂/ kg of hydrogen, whereas the carbon footprint of grey hydrogen ranges from 10–20 kg CO₂/ kg.

This type of green hydrogen is also interesting in terms of costs; according to the International Energy Agency (IEA), producing hydrogen from fossil fuels is currently the lowest-cost option (€0.46–1.8/kg of hydrogen). Hydrogen production from electrolysis, using green electricity (wind, solar) is much costlier in most places, at €2.5–11.9/kg. The renewable electricity costs can make up 50–90% of total production expenses. Biohydrogen can be obtained at a cost ranging from €1.15–9.65/kg, making it cheaper than hydrogen from electrolysis.

Green hydrogen from biogas 
Different technologies are available today to produce biohydrogen. One of the options is to obtain it from biogas production. This is the aim of the TITAN project, started in 2022 and looking to develop and validate the direct conversion of biogas into valuable carbon materials and hydrogen, in a catalytic pyrolysis process within microwave-heated reactors by September 2026.

TITAN would consist of two consecutive catalytic steps without any expensive gas separation prior or after the steps typically achieved by pressure-swing adsorption (PSA) processes.

First, inside the reactor is a fluidised bed of an iron-based catalyst heated by microwave. That directly converts biogas to a syngas mixture (carbon monoxide (CO) + hydrogen (H2)).

Second, a conventional Fischer-Tropsch catalytic process converts syngas to liquid hydrocarbons or alcohols.

Two laboratory scale microwave reactors are being built at Lyon and Warsaw universities for up-scaling studies. A scaleup reactor 10 times larger will be tested in 2025.

The biohydrogen produced via the TITAN technology can be used as a renewable energy source. The benefits of carbon will be studied for application on soil, to enhance agriculture soil properties, as well as for the production of silicon carbide (SiC), a versatile material with a wide range of industrial applications.

The carbon does not contain any polyaromatic hydrocarbons in its porous structure. The structure is relatively well organised on local and long range, approaching graphite structure.

Currently, the production of carbon materials contains a significant amount of iron, which in soil applications is not an issue. The project team is looking for alternative pathways, such as in the steel industries for which iron-carbon materials would be valuable.

Biohydrogen is well placed to help sectors with limited decarbonisation options to achieve carbon-neutrality. Industries that could benefit from this include steel, iron and chemical production.

Diversifying biogas plants 
Additionally, the production of biohydrogen enables biogas producers to diversify their outputs and increase the flexibility and versatility of biogas plants. The biogas sector in Europe has witnessed significant growth and development in the last decade, driven by the urgent need to transition towards cleaner and more sustainable energy sources.

Europe’s biogases production (combined biogas and biomethane) in 2022 amounted to 21bn m³. This is more than Poland’s entire inland natural gas demand and represents 6% of the EU’s natural gas consumption in 2022. Biomethane production alone grew from 3.5bn m³ in 2021 to 4.2bn m³ in 2022. In the case of Denmark, the share of biomethane in the gas grid was close to 40% and there are plans to increase this production to substitute 100% of the gas demand before 2030.

Apart from generating renewable energy, biogas plants play a crucial role in Europe’s renewable energy landscape, providing a sustainable remedy for waste management and offering a promising solution to mitigate GHG emissions.

Biogas upgrading to biomethane and its subsequent broader end-use applications is the fastest growing segment of the biogas industry. For those plants that are not upgrading the biogas to biomethane, the TITAN technology offers an interesting alternative to valorise the biogas.

With the current levels of biogas production, the sector would be able to cover around 33% of Europe’s total hydrogen demand. The most suitable market segments for the implementation of the TITAN technology include small biogas plants, plants far from grid connection, plants with no subsidies/incentives for electricity production, plants near hydrogen and/or carbon materials demand areas, plants with surplus of production, and diversified energy mix scenarios.

Future-proofed energy systems 
Biohydrogen could contribute to defossilise our energy system, but also to fuel diversity and energy system flexibility. Flexibility, in the form of flexible operations and power generation, stronger grids, more energy storage, and demand response, is paramount in enabling the transition to a power system dominated by renewables, which will include increasing quotas of variable sources providing fluctuating levels of electricity.

In rural areas where there could be a future need for hydrogen, biohydrogen can be produced from raw biogas or biomethane to provide a local source of green energy. This approach lowers costs for remote locations, as the expense associated with hydrogen transport is avoided. At the same time, recent innovation aims to increase the methane yield at anaerobic digestion plants by combining hydrogen with raw biogas. The CO₂ present in the biogas can then combine with hydrogen to form additional biomethane.

Beyond energy 
The additional positive externalities that the biogas sector, including biohydrogen, delivers are currently not fully rewarded by policy makers or recognised by society at large. Today, producers of renewable gases are primarily rewarded for contributing to renewable energy targets via support or market-based mechanisms.

The TITAN project has the potential to produce 0.6mn t/y of green hydrogen by 2030 and almost 4mn t/y from 2045 onwards, corresponding to the saving of 237mn tonnes of CO₂ by 2045. It could provide around 40,000 jobs by 2030 and 103,000 jobs by 2050, and an economic revenue in a range of €1.4–1.6mn and €4.1–9mn if 10% of the total biogas production today was used for biohydrogen production in 2030 and 2050, respectively.

As happens with many innovative products, the regulatory framework has not yet fully adapted to allow biohydrogen to reach commercial maturity. An enabling EU regulatory framework could be achieved by enforcing legal and market recognition, driving market access via consumption targets, using taxation to send a price signal in support of renewable sources of hydrogen, and facilitating network access.