Green Hydrogen: what is it, pros and cons

The lowdown on green hydrogen

As the climate crisis worsens, the search for new forms of energy becomes increasingly pressing. Alongside renewable energy, nuclear power, biomass, and geothermal energy, hydrogen is considered one of the primary alternatives to our rapidly depleting supply of fossil fuels when it comes to powering our way of life. The race is on to determine which of these alternatives is capable of replacing fossil fuels and how we can begin to transition our energy reliance in a more long-term fashion towards a secure energy future. Hydrogen energy plays a key role in current research and development, with green hydrogen taking center stage.

What is green hydrogen?

The most abundant naturally occurring chemical element, hydrogen is a colorless gas. Green hydrogen, also known as GH2, is a term used to refer to hydrogen generated through the electrolysis of water using renewable energy. Within the industry, hydrogen energy is color coded to differentiate between the different types—as well as green hydrogen, there is blue hydrogen, brown hydrogen, and even turquoise hydrogen! Green hydrogen is believed to be the “cleanest” method of producing hydrogen.

What is green hydrogen energy?

Many countries have set themselves the goal of decarbonizing completely by 2050. Decarbonizing hydrogen and creating green hydrogen is key to achieving this. Green hydrogen technology is based on generating hydrogen—a light, universal, and reactive fuel—through the chemical process of electrolysis. An electrical current is used to split the hydrogen and oxygen in water apart. If the electricity used to power the current is also generated from renewable sources, this green hydrogen will be produced without the emission of carbon dioxide into the atmosphere, thus making it completely “green.” This process of producing green hydrogen is one of three main ways in which hydrogen is currently generated—the other two are known as grey hydrogen and blue hydrogen. Grey hydrogen, which makes up the bulk of the prevailing hydrogen market, is obtained through the thermal conversion of natural gas, which still results in a significant quantity of carbon dioxide. Blue hydrogen is less polluting—derived from the grey hydrogen method, this is followed by carbon recovery and storage, reducing the emission of greenhouse gases into the environment.

How is green hydrogen obtained?

Green hydrogen is obtained by electrolysis from renewable sources. The water (H2O) to be broken down by the electrolysis must contain minerals and salts in order to conduct the electricity. Two electrodes are initially immersed into the water before being connected to a power source and switched on. The hydrogen and oxygen are separated when these electrodes attract ions with an opposite charge. The electrolysis promotes an oxidation-reduction reaction due to the effect of the electricity.

What are the problems with green hydrogen?

Like most energy sources, green hydrogen comes with both advantages and disadvantages. Although it is 100% sustainable and versatile, green hydrogen is expensive to produce due to the cost of energy from the renewable sources that are key to generating green hydrogen through electrolysis. It requires more energy than other fuels to produce any kind of hydrogen, green in particular. Finally, hydrogen is extremely volatile and flammable, meaning that comprehensive safety measures need to be implemented to prevent explosions or leakage. This also makes hydrogen difficult to both store and transport.

What are the latest developments in green hydrogen?

There is plenty of news from the world of green hydrogen. Hydrogen as a fuel is already a reality in some countries, such as the US, Russia, China, Germany, and France, with other nations going even further in their research.

The versatility offered by hydrogen makes it ideal for specific areas that provide a challenge when it comes to decarbonization, such as heavy industry, aviation, and maritime transport. Recent years have seen the initiation of a number of projects, particularly within the EU, aimed at introducing hydrogen as a fuel for passenger aircraft, although it is likely to be several decades until this becomes a reality.

Research is ongoing into the use of natural gas pipelines to transport hydrogen, although this does require the pipelines to be upgraded. A pilot program in France has already mixed hydrogen into the gas grid of 100 homes. There is also the potential to convert natural gas power plants to burn hydrogen as a backup during spells of excessive demand.

One interesting field of development involves investigation into the possibility of producing green hydrogen through the electrolysis of seawater in order not to further deplete the Earth’s freshwater supplies.

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