The role of hydrogen electrolysers in sustainable energy

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The dependence on fossil fuels for power generation has come at a significant environmental cost. Combustion of coal, oil, and natural gas accounts for more than half of global CO₂ emissions, contributing heavily to climate change and air pollution. According to the World Health Organization, air pollution causes 6.7 million premature deaths annually, underscoring the urgent need for cleaner energy solutions. Meanwhile, an Intergovernmental Panel on Climate Change (IPCC) has warned the need to limit global warming to 1.5°C. This has necessitated rapid and far-reaching transition towards energy systems, emphasizing the urgency for sustainable alternatives.

Globally, there is a growing recognition of the need for sustainable alternatives to fossil fuels. Renewable energy sources like solar, wind, and hydropower are seeing increased investments, with global renewable capacity reaching 2,799 GW in 2020, according to the International Renewable Energy Agency (IRENA). However, these sources alone may not be sufficient to meet the ever-increasing energy demands of a rapidly developing world. The International Energy Agency (IEA) reports that to achieve net-zero emissions by 2050, hydrogen could meet up to 10% of global energy needs. This is where hydrogen, often dubbed the “fuel of the future,” comes into the picture as a versatile and clean energy carrier.

A clean fuel for our future

Hydrogen, when produced through electrolysis using renewable energy, offers a promising solution to the clean energy puzzle. This fuel-source stands out as a remarkably versatile energy carrier capable of transforming multiple sectors, including power generation, transportation, and industrial processes. Hydrogen electrolysers split water into hydrogen and oxygen, producing zero greenhouse gas emissions in the process. Green Hydrogen, according to the IEA is expected to reduce CO₂ emissions by 6 gigatonnes annually. This makes hydrogen not only a clean energy carrier but also a cornerstone of a sustainable and resilient energy future.

The hydrogen electrolysing technology not only provides a sustainable method of generating hydrogen but also has the potential to revolutionize the energy landscape by enabling large-scale storage and transportation of clean energy. Since hydrogen plays a crucial role in industrial processes such as steelmaking and chemical production, it also has the propensity to replace carbon-intensive methods and reduce overall emissions. That, if the industry can control the way hydrogen is electrolysed.

Although hydrogen is produced through various methods, the method of generating it by burning fossil fuel is the least efficient method. Hydrogen electrolysers are at the heart of the green hydrogen revolution, converting renewable electricity into clean hydrogen fuel by passing an electric current through water to split its molecules into hydrogen and oxygen.

Demystifying hydrogen electrolysers

There are several types of hydrogen electrolysers available today, each with distinct advantages and limitations.

Proton Exchange Membrane (PEM) electrolysers are known for their efficiency and ability to operate at high current densities. They use a solid polymer electrolyte and are valued for their fast response times and compact design, making them suitable for applications where space is a premium and flexibility is key. However, they tend to be more expensive due to the use of precious metals as catalysts.

Alkaline electrolysers, on the other hand, have been around for decades and are renowned for their durability and lower capital costs. They use a liquid alkaline electrolyte, such as potassium hydroxide, and are best suited for large-scale, steady-state operations.

Meanwhile, Solid Oxide Electrolysers (SOEs) are a newer technology that operates at high temperatures, improving efficiency but requiring more robust materials to withstand the operating conditions.

When choosing the type of electrolyser for a specific application, several factors need to be considered, including efficiency, cost, and operational requirements. For instance, PEM electrolysers, despite their higher cost, may be preferred in environments where rapid startup and shutdown cycles are necessary, such as in renewable energy integration with variable power output. Alkaline electrolysers, with their lower operational costs, might be more suitable for large-scale industrial hydrogen production where continuous operation is possible. The choice of electrolyser ultimately depends on the specific needs of the application, balancing factors such as capital expenditure, operational efficiency, and the nature of the energy source available.

Electrolysers at the grid

Hydrogen electrolysers are emerging as key players in grid balancing and energy storage strategies worldwide. By converting excess renewable electricity into hydrogen during periods of low demand, electrolysers offer a scalable solution to store energy for later use.

According to Bloomberg-NEF, hydrogen storage systems could potentially meet up to 24% of global electricity demand by 2050, providing critical support for intermittent renewable energy sources. Unlike traditional batteries, which are limited by their capacity and discharge rates, hydrogen storage systems can scale up to meet extensive energy demands. According to a study by the Hydrogen Council, hydrogen can store energy for longer periods and in larger quantities than current battery technologies, with the ability to provide long-term seasonal storage.

This explains why countries such as Germany and Japan have taken a hydrogen-first approach. Hydrogen’s capability not only helps in mitigating the variability of renewables but also reduces curtailment rates, as evidenced by initiatives in countries like Australia and the Netherlands. Furthermore, the European Commission estimates that hydrogen storage could contribute to the reduction of curtailment of renewable energy by up to 50% by 2050, highlighting its critical role in future energy infrastructures.

Towards a sustainable future

As the engine of global growth, developing nations like India hold immense potential in shaping the clean energy landscape, despite a bumpy road ahead. The initial cost of electrolyser technology is nonetheless massive. Also, installing electrolysers is akin to planting saplings, they need continuous nurturing through research and development. But, despite the challenges, hydrogen electrolysers have a tall potential. As technology matures, costs may plummet and guide countries like India towards a sustainable future.

The views and opinions expressed in this article are the author’s own, and do not necessarily reflect those held by pv magazine.

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