Frequently Asked Questions

Green hydrogen refers to hydrogen gas produced by the electrolysis of water, using electricity obtained from renewable sources such as wind or solar energy. This process is known as "electrolysis." The term "green" is used because no greenhouse gases are emitted during the production of hydrogen using this method.

The electrolysis process involves the separation of water into hydrogen and oxygen using an electric current. The produced green hydrogen can be used as a raw material in industry and in various applications, such as powering vehicles or generating electricity, without leading to carbon dioxide or other greenhouse gas emissions when utilized.

Production

• Electrolysis uses electricity to split water (H2O) into hydrogen (H2) and oxygen (O2).
• The renewable energy source powering the electrolysis is crucial for making it "green."

Applications of Green Hydrogen

Transportation:

• Fuel cell electric vehicles (FCEVs): These vehicles use hydrogen in a fuel cell to generate electricity and power the motor. Unlike battery-electric vehicles, FCEVs have faster refueling times and longer ranges, but infrastructure and vehicle affordability are current hurdles.
• Heavy-duty vehicles: Trucks, buses, and ships are difficult to electrify directly, making green hydrogen a promising alternative with high energy density and zero emissions.
• Aviation: While still in early stages, research explores using green hydrogen in fuel cells or synthetic fuels for airplanes, potentially decarbonizing this hard-to-electrify sector.

Power generation:

• Grid balancing: Green hydrogen can be stored and used to generate electricity during peak demand periods, smoothing out the fluctuations from renewable sources like solar and wind.
• Standalone power: In remote areas or for off-grid applications, hydrogen fuel cells can provide clean and reliable power generation.

Industry:

• Steel production: Replacing coal with green hydrogen in steelmaking processes can significantly reduce carbon emissions in this heavy industry.
• Chemical production: Ammonia, methanol, and other chemicals can be synthesized using green hydrogen, offering a pathway to decarbonize various industrial processes.
• Heating: Blending green hydrogen with natural gas or using it directly in fuel cells can be a cleaner option for heating buildings and industrial facilities.

Benefits:

• Zero emissions: Unlike traditional hydrogen production methods that rely on fossil fuels, green hydrogen doesn't produce greenhouse gases or air pollutants.
• Versatility: Hydrogen can be used for various purposes, including power generation, transportation, and industrial applications.
• Energy storage: Green hydrogen can store excess renewable energy, helping to overcome the intermittent nature of wind and solar power.

Challenges:

• Cost: Currently, green hydrogen is more expensive than traditional hydrogen due to the cost of electrolysis and renewable energy infrastructure.
• Infrastructure: Scaling up production and distribution infrastructure requires significant investment and technological advancements.
• Storage and transportation: Hydrogen requires special infrastructure for storage and transportation, which can be costly and complex.
• Efficiency: The entire process of generating, storing, and using green hydrogen involves energy losses, making it crucial to optimize technology and infrastructure for maximum efficiency.

Overall, green hydrogen is seen as a promising solution for decarbonizing our energy system and achieving net-zero emissions. Although challenges exist, significant research and development efforts are underway to address them and make green hydrogen a viable and competitive clean energy option.

1. Electrolysis: This is the leading method for clean hydrogen production and uses electric current to decompose water into hydrogen and oxygen. The most important aspect of this process is the source of electricity:

• Electrolysis with renewable energy sources: Unlike conventional methods that rely on fossil fuels as the energy source, water electrolysis powered by electricity derived from renewable sources such as solar or wind enables green hydrogen production without carbon dioxide emissions. This method is critical for decarbonizing various sectors, including transportation, heavy industry, and heating.
• Low-carbon grid electrolysis: If the electricity grid is largely powered by renewable sources, using it for electrolysis can reduce carbon dioxide emissions compared to relying on fossil fuels.

2. Biomass gasification: In this method, organic materials such as wood chips, agricultural waste, or even algae, referred to as biomass, are converted into hydrogen and other gases. If the biomass is obtained from sustainable resources, the hydrogen produced through this method can be considered clean.

3. Thermochemical water splitting: This method uses high temperatures generated by nuclear reactors or concentrated solar energy to split water into hydrogen and oxygen without electricity. Although this method shows promise, it is still under development due to scalability and cost disadvantages.

4. Photoelectrochemical water splitting: This innovative approach mimics the process of photosynthesis to split water directly into hydrogen and oxygen using sunlight and specialised semiconductors. While potentially promising in the long term, it is currently not a mature technology and needs technological advances to become commercially viable.

5. Carbon capture and storage (CCS): This method is based on the use of conventional hydrogen production from fossil fuels, such as natural gas, and the capture and storage of the resulting carbon dioxide emissions. While the hydrogen produced through this method is not considered entirely clean due to the initial emissions, it can be an important step in transitioning to cleaner methods.

The classification of hydrogen production as "clean" depends not only on the production method but also on the energy source used for electrolysis, and the efficiency of the infrastructure. Choosing the right method is influenced by various factors, such as resource availability, cost, infrastructure, and regional policies. Thanks to ongoing research and development efforts, new and cleaner production methods for hydrogen are being developed. As a result, hydrogen is becoming a key player in the pursuit of a sustainable energy future.

In the context of a future powered by green hydrogen, various critical hydrogen derivatives emerge as key players in reducing carbon emissions across different sectors and overcoming the limitations of pure hydrogen

1. Ammonia (NH3):

• Benefits: Ammonia can be used as a clean fuel in ships, trucks, and power plants. It is easier to store and transport than hydrogen, requiring less volume and existing infrastructure. Ammonia synthesis powered by green hydrogen also offers a pathway to decarbonize the fertilizer industry.
• Challenges: Ammonia production today is heavily dependent on fossil fuels, resulting in greenhouse gas emissions. The production of green ammonia using green hydrogen is vital for decarbonisation. Furthermore, the combustion of ammonia releases oxides of nitrogen, thus requiring control technology for clean emissions.

2. Methanol (CH3OH):

• Benefits: Methanol offers a near-term decarbonization solution for the transportation sector as it can be blended with gasoline for use in existing vehicles. It can also be used in fuel cells to generate electricity. The use of green methanol, produced with green hydrogen, as a fuel and chemical feedstock is crucial for a sustainable future.
• Challenges: Methanol production is heavily dependent on fossil fuels. Additionally, since harmful gases like NOx are released during the combustion of methanol, mitigation strategies are required.

3. Synthetic fuels (Synfuels):

• Benefits: Synthetic fuels such as e-kerosene and e-diesel can directly replace fossil fuels in existing airplanes and heavy vehicles without requiring infrastructure changes. They offer high energy density and long range, making them suitable for aviation and long-distance transportation.
• Challenges: Synfuel production using green hydrogen is currently energy-intensive and more expensive than conventional fuels. Technological advancements and cost reductions are necessary for wider adoption.

4. Hydrogen carriers:

• Benefits: Certain materials, such as organic liquid carriers or metal hydrides, can store hydrogen more efficiently than in gaseous form, facilitating easier transportation over long distances. This provides flexibility for the utilization of hydrogen in areas lacking direct access to production facilities.
• Challenges: The development of efficient and cost-effective hydrogen carriers is an ongoing process. Striking the right balance between storage capacity, ease of release, and cost remains a challenge. Additionally, other potential derivatives, such as hydrogen chloride (HCl) for industrial applications or hydrogen peroxide (H2O2) for clean bleaching processes, are also being explored. Consequently, critical hydrogen derivatives will depend on specific applications and regional needs. A combination of these derivatives, alongside ongoing research and development efforts, will play a crucial role in unlocking the full potential of green hydrogen and achieving a truly carbon-free future.