Traditional liquid alkaline electrolysers have been available for some time and are fairly inexpensive. However, their slow response to fluctuating power supply makes it challenging and costly to efficiently pair them with renewable energy sources.
These traditional alkaline electrolysers use highly concentrated electrolyte solutions and operate at low pressure, necessitating extra purification and compression steps to produce high-quality gas at higher pressure. This is cost-effective mainly for centralised, large-scale multi-MW projects.
The AEM electrolyser borrows from the strengths of traditional alkaline electrolysers, while avoiding their weaknesses:
AEM electrolysis occurs in a heavily diluted alkaline environment, making it much safer.
AEM electrolysers can use similarly affordable materials but generate purer, more efficient hydrogen.
AEM electrolysers are fully scalable and ideally suited for integration with fluctuating renewable energy sources.
Proton exchange membrane electrolysers (PEM) employ a semi-permeable membrane composed of a solid polymer designed to conduct protons. Despite their flexibility, fast response time, and high current density, the widespread commercialisation of PEM electrolysers remains challenging due mainly to the costly materials required for long-lasting performance. Particularly, PEM electrolyser cells’ highly acidic and corrosive environment necessitates expensive noble metal catalyst materials (iridium, platinum) and significant amounts of costly titanium, creating a scalability issue.
Anion exchange membrane electrolysers utilise a semipermeable membrane designed to conduct anions. They provide a viable alternative to PEM, sharing the same strengths while offering several critical advantages leading to lower costs. Due to the environment’s less corrosive nature, steel can be used instead of titanium for the bipolar plates. Plus, AEM electrolysers can handle a lower degree of water purity, simplifying the input water system and allowing for filtered rain and tap water.
Hydrogen weighs 0.08988 g/L or 0.08988 kg/Nm³.
Hydrogen’s energy content is expressed by its lower and higher heating values. Hydrogen’s lower heating value can be stated as 33.33 kWh/kg or 3.00 kWh/Nm³, and its higher heating value is 39.39 kWh/kg or 3.54 kWh/Nm³. The lower heating value of 3 kWh/Nm³ is typically used if the hydrogen isn’t directly burned. A practical value to remember is approximately 3 kWh/Nm³. The energy content of 1 Nm³ (=1000 NL) hydrogen gas is equivalent to 0,36 L gasoline, 1 L liquid hydrogen is equivalent to 0,27 L gasoline, and 1 kg hydrogen is equivalent to 3.3 kg gasoline (based on the lower heating value).
Like any gas, hydrogen is flammable, and appropriate safety measures must be ensured when handling it. However, hydrogen’s properties make it safer to handle than many commonly used fuels. It is non-toxic and lighter than air, allowing it to quickly disperse in the event of a leak. When planning a hydrogen system installation, it’s crucial to implement appropriate safety measures, such as ventilation and leak detection.
When properly stored, there are no losses. Unlike diesel, for instance, hydrogen does not have an expiry date and can be stored for years.
We’ve reached a critical juncture in our understanding of energy. Solar and wind are the two fastest-growing energy sources. As governments and industries increasingly recognise the limitations of fossil fuels, the challenge remains to harness solar and wind power when we need it. Variable renewables are competitive, and customers are demanding a reliable, secure, and independent energy supply from sustainable sources. On-site green hydrogen production facilitates complete green energy independence and security. A burgeoning global industry is emerging around hydrogen’s potential as a storable fuel or energy carrier, with numerous advantages over battery-electric technology leading to hydrogen gaining traction with industry, environmentalists, and leading governments.
Around 99% of the world’s hydrogen is still produced from fossil fuels, primarily via steam methane reforming of natural gas, a process that emits significant greenhouse gases. Green hydrogen refers to hydrogen made from water using an electrolyser powered by renewable energy sources. Hydrogen acts as a bridge between renewable power generation and other types of energy vectors, enabling us to clean more than just the electricity sector with fossil-free fuels.
Hydrogen is an energy carrier with a variety of applications. Today, it is primarily used directly in various industrial processes, including ammonia fertiliser production, food processing, the float glass industry, cooling for power plants, and in the semiconductor and electronics industry, among others.
Hydrogen is also used as a fuel in transport, often emitting only water as a byproduct.
The HYScale is CENmat’s groundbreaking water electrolyser system designed for efficient and scalable green hydrogen production. It utilizes an innovative anion exchange membrane (AEM) technology to split water into hydrogen and oxygen gas.
The HYScale stands apart due to its high current density operation, compact and simplified design, lack of reliance on critical raw materials, and capability to directly connect to renewable energy sources. These features enable low capital and operating costs, flexibility, and sustainability.
The HYScale uses CENmat’s proprietary ion exchange membranes and electrocatalysts to split water molecules. The water splitting reaction begins at the cathode where the alkaline environment promotes hydrogen evolution. The hydroxide ions generated at the cathode flow through CENmat’s AionFLX anion-exchange membrane to the anode. At the anode, the hydroxide ions react to form oxygen gas and water.
The HYScale dramatically lowers costs through its high current density (up to 2 A*cm-2), compact size, simplified production, lack of reliance on scarce materials, and capability to directly use renewable electricity. Together, these factors substantially cut capital and operating expenditures.
The HYScale’s innovative catalyst-coated electrode approach enables straightforward, high-volume production using standard industrial equipment. This allows rapid scaling to meet rising hydrogen demand.
The HYScale is designed to minimize environmental impact through its small footprint, lack of critical raw materials, low electricity consumption, and ability to directly use renewable energy. This aligns with sustainable hydrogen production.
The compact, flexible HYScale design allows deployment in diverse locations, including isolated, off-grid sites with renewable power generation. Its independence from the electrical grid facilitates wide rollout.
Unlike conventional alkaline or PEM electrolysers constrained by materials limitations and complexity, the HYScale overcomes these barriers through innovative materials science and simplified engineering for superior efficiency.