Hydrogen

Stainless steel for hydrogen economy applications

Producing, processing, storing, and using hydrogen require robust materials that can withstand high pressures as well as both extremely low and high temperatures. Additionally, producing end-to-end sustainable hydrogen solutions requires sustainably produced materials. Outokumpu stainless steels are ideally suited to meet these challenges.

Stainless steel is vital for the low-carbon hydrogen economy

Pure hydrogen is increasingly recognized as the ultimate clean fuel, thanks to its combustion process which yields only energy and water.

The anticipated fast growth in the hydrogen economy calls for stainless steel. While some applications are technically established, others are currently emerging, and a sustained R&D effort is required to keep up with the material challenges they present. At Outokumpu, our efforts are underpinned by close cooperation with universities and industrial partners to develop stainless steel solutions for emerging innovative hydrogen applications. One great example is the ongoing work on solid oxide fuel cells (SOFCs).

Stainless steel offers the ideal combination of high strength, corrosion resistance, and performance to make an important sustainability contribution as the world strives for Net Zero. While this is happening, we are seeing a broader understanding of how flexible, sustainable hydrogen can complement global energy distribution and storage, and as a chemical, e.g. replacing coke in the reduction of iron ore to iron. This will significantly boost energy security, access, and economic development while also reducing air pollution.

Stainless steel offers excellent strength and safety in hydrogen storage

For many storage and transportation applications, hydrogen is liquified, requiring its temperature to be reduced to as low as -253°C. Austenitic stainless steel grades are ideal for use at cryogenic temperatures as they offer a safety-essential combination of ductility and energy absorption.

Another approach to storage and transportation is to compress gaseous hydrogen. Due to its low volumetric density, this demands high pressures of up to 800 bar. In some materials, this could result in hydrogen embrittlement, where the diffusion of the gas into the surface eventually leads to cracking. The preferred material to meet this challenge is austenitic stainless steel, as hydrogen diffusion is much lower in austenite than in ferrite or martensite. Excellent material resistance to hydrogen embrittlement in high pressure applications is obtained by selecting stable austenitic steel grade, such as Supra 316L/4435. Supra 316plus/4420 and Supra 316LN/4429 also present excellent alternatives, especially when higher material strength is needed.

Since many storage facilities are built in coastal areas with a salt-laden environment, the corrosion resistance of stainless steel is an increasingly important factor.

Read more about hydrogen storage tank solutions

Storing energy in hydrogen reduces reliance on fossil fuels


Storing energy in hydrogen is an efficient and versatile method for balancing energy supply and demand. Hydrogen can be produced via electrolysis using surplus renewable energy, such as wind or solar power. Once produced, it can be stored in tanks and later converted back into electricity using fuel cells, for example.

This process helps stabilize the grid, reduces reliance on fossil fuels, and enables the integration of more renewable energy sources into the energy system. Hydrogen storage is scalable and can be used for various applications, from powering vehicles to providing backup power for industries and homes. The natural extension from storage is filling stations, such as refueling a fuel cell vehicle. The properties of stainless steel make it ideal for the manufacture of fuel dispensers, tubes and compressors. Outokumpu stainless steels offer ideal material choices for all of these applications.

Applications and benefits of stainless steel in industrial hydrogen applications

Applications

  • Hydrogen storage and pipelines
  • PEM fuel cells and electrolyzers
  • Solid oxide fuel cells and electrolyzers
  • Tank systems on vehicles
  • Systems at fuel stations

Benefits

  • High strength
  • High ductility also at low temperatures
  • Long service life; low life-cycle costs
  • High resistance to hydrogen embrittlement

Fuel cells and electrolyzers benefit from high-quality stainless steel

A fuel cell converts hydrogen and oxygen into energy and water, while an electrolyzer uses energy and water to create hydrogen and oxygen. Stainless steel can be used in many different fuel cell and electrolyzer components such as interconnectors, the substrate for bipolar plates, anode and cathode plates, endplates, frames, and connecting parts. The most suitable grade depends on the operating temperature and environmental conditions. The strength and corrosion resistance of stainless steel enables the dimensions, and especially the thickness of components, to be optimized in terms of size and weight.

Bipolar plates are very demanding on materials. They must combine gas impermeability and tightness, good electrical and thermal conductivity and a high level of physical strength. Stainless steel has emerged as a very strong contender for cost-effective mass production in hydrogen bipolar plates. Outokumpu’s own investigations indicate that austenitic grades, such as Supra 316L/4404, are the current state-of-the-art as they offer the ideal combination of electrical conductivity, high corrosion resistance, excellent formability, and high strength.

Outokumpu also has a very good offering for the demandingly high operating temperatures of the solid oxide fuel cell (SOFC) technology. Two commercially available Outokumpu ferritic grades of stainless steel, Core 4622 and  Core 441/4509, have been identified as candidate materials and are currently under investigation in SOFC prototypes.

Read more about our stainless steels for bipolar plates

Stainless steel enables clean water for electrolysis

The raw water used in the electrolysis process needs to be clean to ensure that the expensive catalyst lasts as long as possible. Stainless steel is ideal for components used in water purification and desalination processes. The grade specified will depend on the water composition—mainly chloride content and temperature. The grades used are from Outokumpu Supra to Ultra range, and when the higher mechanical strength can be utilized, the Forta Duplex range is an excellent alternative.

Supporting sustainability efforts in hydrogen applications

Outokumpu stainless steel sets an industry standard for sustainability. With a focus on the economic and environmental aspects of the full lifecycle of the material, we help our customers reduce their value chain emissions—the most challenging emissions to reduce. Stainless steel’s inherent sustainability qualities include unmatched longevity and durability, low maintenance requirements, and closed-loop recyclability—meaning that it is 100 % recyclable. This way Outokumpu stainless steel offers a means to complement the sustainability of different hydrogen applications from the construction to the end of the lifecycle.

More about Outokumpu's sustainability efforts and research

Related Information

Supra
Forta
Ultra
Therma

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