[Hydrogen Economy, Companies Leap] The Future Energy is Coming... The Life Cycle of Hydrogen

What is Hydrogen and Why Is It Gaining Attention Now?
Value Chain and Next-Generation Energy Hegemony Shaken
Key to Building a Global Full-Cycle Ecosystem

'The lightest element on Earth.' That phrase refers to me. I am hydrogen, the element with atomic number 1. Yes, atomic number 1 is me. I have one proton and one electron, so I am small in size, but I make up most of our universe, accounting for 75% of the total elemental mass in the cosmos. I am common, yet my value has been soaring recently. You might have heard somewhere that the hydrogen economy is approaching. That’s because I am being recognized as a future energy source to replace fossil fuels. Would you like to hear my success story?

My name, hydrogen (水素, Hydrogen), comes from the Latin word 'hydro,' meaning water. Literally, I am the element that makes water. About 250 years ago, in 1766, a British scientist named Henry Cavendish first discovered me, and the French chemist Antoine Lavoisier, known as the father of modern chemistry, gave me my name.

My boiling point is very low, at minus 253 degrees Celsius. So, I exist as a gas at room temperature. However, it is rare to find pure hydrogen molecules in nature. Instead, I exist combined with other elements like carbon or oxygen as compounds. Water, made of two hydrogen atoms and one oxygen atom, is a representative example. In fact, I am present in all substances that make up humans, animals, and plants. For a long time, humans and I have had an inseparable relationship.

I have also been widely used in industrial fields. I am used to synthesize ammonia and methanol, and as a desulfurizing agent to remove sulfur from petroleum. I play roles in various fields, from cosmetics and pharmaceuticals to semiconductors, and the places that seek me are countless. Globally, the consumption volume exceeds 100 million tons, so you can guess my popularity to some extent.

However, producing me is a bit complicated. I must be separated from compounds through a process. There are many ways to produce me, so we classify them by color.

Hydrogen Full-Cycle Ecosystem Diagram (Source: Korea National Oil Corporation)

Until now, I have mainly been produced by reacting hydrocarbons with steam or oxygen, or as byproducts in petroleum refining and the production of caustic alkali and chlorine. This is called reforming hydrogen and byproduct hydrogen, and the hydrogen produced this way is called 'gray hydrogen.' It is the cheapest production method but has a problem: carbon dioxide is emitted during production.

If the carbon dioxide emitted at this stage is captured and stored, the name changes to 'blue hydrogen.' This means it is closer to being environmentally friendly. Since only carbon dioxide capture and storage (CCS) facilities need to be added to existing production plants, it is considered the most realistic hydrogen production method. However, how to store the captured carbon dioxide is another concern. Plans are underway to store it in deep underground coal mines, oil fields, or deep seas, but the impact on ecosystems is unknown. Therefore, methods to reuse carbon dioxide are also being considered.

When water is electrolyzed to produce hydrogen, no carbon dioxide is emitted. This is called 'green hydrogen.' It is also called water electrolysis technology but has not yet achieved economic feasibility or stability. So, until clean hydrogen production technology is secured, blue hydrogen must buy time.

The electricity used to produce green hydrogen must also be generated from carbon-free renewable energy. In Jeju Island, production facilities that obtain hydrogen by electrolyzing water with electricity generated from solar and wind power are already in operation. However, since renewable energy generation times and amounts fluctuate, developing electrolysis technology that can operate stably under such conditions is important.

When electricity generated by carbon-free nuclear power is used for production, it is called 'pink hydrogen.' In South Korea, where renewable energy production is geographically challenging, pink hydrogen could be an alternative. This is because the cost of producing green hydrogen is very high.

Plans for Creating a Clean Hydrogen Ecosystem (Source: Korea International Trade Association)

The International Renewable Energy Agency (IRENA) estimated that by 2050, the cost of producing green hydrogen in South Korea could reach up to $4.1 per kilogram. While most countries worldwide can produce green hydrogen for less than $2, this is very disadvantageous. Japan also faces a similar situation with production costs exceeding $3. Since it is clear that South Korea will become an importer of green hydrogen in the future, it is wise to prepare various alternatives.

Storage and transportation technologies are as important as production. Since I am a gas at room temperature, storing me as is takes up a lot of space. Therefore, I must be compressed at high pressure or liquefied. The high-pressure tanks mainly used in hydrogen vehicles operate at 700 bar. This is an enormous pressure 700 times atmospheric pressure (1 bar). Because of this, storage and refueling facilities must safely withstand such high pressure. Storage tanks mainly use high-density plastics and carbon fiber, which is stronger than steel.

To liquefy me, the temperature must be lowered below minus 253 degrees Celsius. Liquid hydrogen has a mass of 71 grams per liter, which is larger than the compressed state at 700 bar (about 40 grams). Liquefying is ideal for storage. However, a lot of energy is required to lower the temperature to cryogenic levels, and insulation technology is crucial. Even with insulation, there is a risk of explosion due to vaporization, so it cannot be sealed completely. Much research is needed.

Because of these reasons, ammonia is attracting attention as a means to store me. Ammonia consists of one nitrogen atom and three hydrogen atoms. Since nitrogen makes up 78% of the air, attaching hydrogen to nitrogen is feasible. Moreover, ammonia can be liquefied at minus 33 degrees Celsius. It is technically easy and less costly.

Hydrogen Economy Activation Roadmap (Source: Ministry of Trade, Industry and Energy)

Once I am produced cleanly and brought to you, it is time to use me well. I can be used anywhere fossil fuels are used. I am already used in some power plants to generate electricity or as fuel for transportation. I am either burned directly or combined with oxygen. Recently, more thermal power plants are adopting co-firing technology that burns me together with LNG. This co-firing technology is also being applied to ship engines to develop hydrogen-powered ships.

The representative method of combining me with oxygen is fuel cells. Simply put, fuel cells are the opposite of water electrolysis, which splits water into hydrogen and oxygen. In fuel cells, hydrogen and oxygen combine to form water, generating electricity in the process. Fuel cell technology has a long history, having been used in the Apollo 11 mission that explored the moon. Currently, it is mainly used in automobiles, but it is expected to be applied to trains and drones in the future.

How do you feel? After looking back on my life from birth to storage, transportation, and consumption, do you understand a bit why I am so popular? Achieving carbon neutrality, which means net zero carbon emissions, is a very difficult task. But it is essential for future generations. Please support hydrogen’s challenge toward carbon neutrality.