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Making green hydrogen even greener

Green hydrogen is produced by using water electrolysis, where PEM electrolysis currently is the most promising. Photo: Scharfsinn/Shutterstock
A new project is making the hydrogen production process more cost effective and sustainable by reducing the use of critical raw materials.

Green hydrogen is a promising alternative to fossil fuels, allowing decarbonization of crucial industry sectors. It can be converted to electricity for use in the transportation sector, as a feedstock for metal production or can be burned to produce heat for use when making cement.

However, one of the challenges in the production of green hydrogen is that materials needed in the process are expensive and hard to find. Many of them have been designated as Critical Raw Materials (CRMs) or have negative environmental impacts. In addition, large investment and electricity costs lead to a prohibitively expensive production cost.

What is green hydrogen?

Hydrogen is becoming an increasingly relevant energy carrier in Norway and Europe. Hydrogen is very energy dense and can be used in sectors as industry, energy, transport and aviation. Around 96 percent all of the hydrogen produced globally today is so-called grey hydrogen, and comes from coal, oil or natural gas. But hydrogen can also be produced from renewable energy, and then we get “green hydrogen”. 

About four per cent of the hydrogen we use today is so-called green hydrogen, and the proportion is increasing. The Norwegian annual production of grey hydrogen is approximately 225,000 tonnes per year. Only a small amount of green hydrogen is produced in Norway today.

A new project funded through the Clean Energy Transition Partnership will seek to solve this by developing and demonstrating new technology for efficient production of green hydrogen.

– The innovations will contribute directly to the increased use of green hydrogen technologies, help Europe reach its emission reduction targets and enhance European expertise in green hydrogen, says researcher at SINTEF, Patrick Fortin.

Changing the electrolysis process

Green hydrogen is produced using a technique called water electrolysis. In this process, renewable electricity is used to split water molecules into hydrogen and oxygen gas. There are two main types of electrolysis in use today: alkaline, and PEM (Proton Exchange Membrane). The alkaline technology has been operating in Norway for almost 100 years (Source:, whilst the SINTEF spin-off company Hystar is an example of a Norwegian company that are set to produce PEM electrolysers.  

The illustration shows the hydrogen value chain, where renewable energy is used to power the electrolyser which produces hydrogen. After this it is either stored, or transported. Illustration: SINTEF

Currently "proton exchange membrane water electrolysis (PEMWE)” is the most promising route towards green hydrogen production. Compared to traditional alkaline electrolysis, PEM electrolysers have higher performance, and can respond to quick changes in power supply, making them ideal for coupling with renewable energy sources.

Lab-scale PEM electrolysers in operation at the Norwegian Fuel Cell and Hydrogen Centre. On the left is a single cell electrolyser, on the right is an electrolyser stack, where several cells are connected in series to produce a significant amount of hydrogen. Photos: Thor Nielsen / SINTEF

However, the major shortcoming of PEMWE is that it needs expensive and rare materials to overcome the harsh operating environment whilst producing high quality gasses in a safe way.

– Today’s commercial PEMWE systems all rely on materials lead to a high cost of the electrolyser and have been identified as critical raw materials, or materials with sustainability/environmental concerns. These materials are noble metal catalysts and protective coatings, titanium-based bipolar plates, and perfluorinated sulfonic acid (PFSA)-based membranes, tells Patrick Fortin. 

In the project’s electrolyser stacks, the critical raw material titanium is replaced with stainless steel, and the iridium loading is decreased by 50 percent. In addition, replacing fluorinated membranes will improve the sustainability, providing more environmental friendly hydrogen production, at a significantly reduced cost.

– The main goal of the project is to develop and demonstrate a proton exchange membrane (PEM) electrolyser stack with increased performance, reduced costs and increased sustainability compared to current PEM electrolyser systems,” says Fortin.

The innovations will be tested initially on a lab-scale before upscaling with the help of the project’s industrial partners.

In the PEMWE process, water is converted into oxygen gas and protons on the anode side of the membrane. These protons move across the membrane to the cathode side where they react with electrons to produce hydrogen gas. This hydrogen can then be transported in pipelines, stored in tanks, and used in industry or transport. Figure: SINTEF

More about the project

The project “Unlocking the Full Potential of Electrolysis with Next-Generation Proton Exchange Membrane Stacks (UNICORN)” is coordinated by SINTEF and has six other partners: Hystar (industry partner, Norway), Alleima (industry partner, Sweden), Research Institutes of Sweden (RISE) (research organization, Sweden), Ionomr Innovations Inc. (industry partner, Canada), The French Corrosion Institute (research organization, France), University of Montpellier/CNRS (academic institute, France).

The main objective of the UNICORN project is to develop and demonstrate a proton exchange membrane (PEM) electrolyser stack with increased performance, reduced CAPEX, and increased sustainability compared to current PEM electrolyser systems. In this project, a 40 kW stack that contains novel, beyond state-of-the-art components will be built and tested during 2000 hours of operation. The project aims to replace expensive platinum group metal (PGM)-coated titanium bipolar plates (BPPs) with low-cost coated stainless steel, reduce the amount of iridium used in the catalyst layer to half of the current commercial standard, and eliminate the use of hazardous fluorinated compounds, specifically perfluorosulfonic acid (PFSA)-based materials, in the membrane and catalyst layers.

The project is set to begin November 1, 2023 and will run for three years. The total budget for the project is 2.94 million €.


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