What are Green Hydrogen Technologies?

As the world accelerates its transition to renewable energy, green hydrogen has emerged as a key player in the fight against climate change. Produced using renewable power to split water molecules into hydrogen and oxygen, it emits zero greenhouse gases. We look at the latest technologies driving green hydrogen production and their transformative potential across industries.

What is green hydrogen?

Green hydrogen is hydrogen gas produced using renewable energy sources, such as wind, solar, or hydropower, to power the water electrolysis process. Unlike grey hydrogen, derived from natural gas, or blue hydrogen, which involves carbon capture, green hydrogen is entirely carbon-free.

Why is green hydrogen important?

1. Decarbonisation:

It enables industries like transportation, manufacturing, and power generation to decarbonise their operations.

2. Energy Storage:

Green hydrogen serves as a medium to store surplus renewable energy for later use.

3. Versatility:

Green hydrogen can replace fossil fuels in applications where electrification is challenging, such as steel production and long-haul shipping.

The potential of green hydrogen to drive the energy transition makes it a priority for governments, researchers, and private companies worldwide.

Technologies in green hydrogen production

Technological advancements are central to making green hydrogen cost-effective and scalable. We share some of the most important innovations:

1. Electrolysis technologies

Electrolysis is the process of using electricity to split water into hydrogen and oxygen. The efficiency and cost of electrolysis systems are critical factors in green hydrogen production.

PEM (Proton Exchange Membrane) electrolysers:

PEM electrolysers use a solid polymer electrolyte membrane to conduct protons. They are compact, responsive to fluctuating renewable energy inputs, and can operate at high pressures, reducing the need for external compressors.

Alkaline electrolysers:

A more mature technology, alkaline electrolysers are cost-effective and widely used. They rely on a liquid electrolyte, typically potassium hydroxide, and are ideal for large-scale hydrogen production.

Solid oxide electrolysers:

Solid oxide electrolysers are high-temperature systems using ceramic materials to conduct ions. They achieve high efficiency by utilising heat, often from industrial processes, to lower the electricity required for electrolysis.

2. Innovations in renewable energy integration

To produce green hydrogen sustainably, renewable energy sources must power electrolysis. Recent innovations include:

Hybrid renewable systems:

Hybrid renewable systems combine solar and wind energy to ensure a steady electricity supply.

Direct coupling:

Designing systems where electrolysis units are directly integrated with renewable power sources, minimising energy losses.

3. Advanced materials for electrolysis

Researchers are developing advanced materials to improve the performance and durability of electrolysers, such as:

Catalysts:

Platinum and iridium are commonly used but expensive. Alternatives like cobalt or nickel-based catalysts are being explored.

Membranes:

Innovations in membrane technology aim to increase conductivity and lifespan.

Green hydrogen: scalability and cost-reduction technologies

Scaling green hydrogen production while reducing costs is essential for its widespread adoption. Key technologies addressing these challenges include:

1. Modular systems for large-scale production

Modular electrolyser systems allow for flexible deployment and scalability. These systems can be installed in smaller units and expanded as demand grows, making them ideal for industries or regions with fluctuating energy needs.

2. Role of AI and IoT

Artificial intelligence (AI) and the Internet of Things (IoT) are transforming hydrogen production by:

• Optimising the operation of electrolysers.

• Predicting maintenance needs to reduce downtime.

• Analysing real-time data to enhance energy efficiency.

3. Energy storage and distribution

Green hydrogen requires efficient storage and transport solutions. Technologies such as liquid hydrogen tanks, compressed gas cylinders, and ammonia synthesis (as a hydrogen carrier) are being refined to improve safety and cost-effectiveness.

Challenges in green hydrogen technology

Despite advancements, green hydrogen faces significant obstacles:

1. High production costs

The cost of green hydrogen is currently higher than grey or blue hydrogen. Renewable energy prices, electrolyser costs, and the efficiency of conversion processes all contribute to this disparity.

2. Infrastructure limitations

The lack of dedicated hydrogen pipelines, storage facilities, and refuelling stations limits the adoption of green hydrogen. Building this infrastructure requires substantial investment and long-term planning.

3. Regulatory and policy barriers

Inconsistent regulations across countries and regions hinder the development of a global green hydrogen market. Policies supporting research, subsidies, and carbon pricing are essential to incentivise production and use.

4. Public perception and awareness

Hydrogen has safety concerns due to its flammability. Addressing public perception through education and transparent safety measures is important for its acceptance.

Green hydrogen trends and potential applications

Green hydrogen is poised to transform energy systems, and several trends indicate its growing influence:

1. Hydrogen-powered heavy industries

Green hydrogen can replace coal and natural gas in industries like steel production, where direct electrification is impractical. Companies such as SSAB and ArcelorMittal are piloting hydrogen-based steelmaking processes.

2. Transportation and mobility

Hydrogen fuel cells are emerging as a viable solution for long-haul trucks, ships, and aviation. Their high energy density makes them ideal for applications where battery-electric solutions are less efficient.

3. Grid balancing and renewable integration

Excess renewable energy can be converted into hydrogen and stored, providing a solution for grid balancing and ensuring a continuous energy supply.

4. Emerging technologies to watch:

• Photocatalysis:

Photocatalysis involves directly splitting water using sunlight, bypassing the need for electricity.

• Thermochemical Processes:

Thermochemical processes harness high-temperature solar concentrators to produce hydrogen.

• Hydrogen Blending:

Mixing hydrogen with natural gas to reduce emissions from existing gas infrastructure.

Green hydrogen represents a transformative opportunity to decarbonise industries and mitigate climate change. Recent advancements in electrolysis technologies, renewable energy integration, and scalable systems have significantly improved its feasibility. However, challenges such as high costs and infrastructure limitations must be addressed to unlock its full potential.

As governments and industries prioritise the energy transition, green hydrogen technologies will play a pivotal role in creating a sustainable, low-carbon future. With continued innovation and investment, green hydrogen is set to become a cornerstone of the global energy system.