Hydrogen production: How is hydrogen made and what is it?

Hydrogen is becoming increasingly important as a promising clean energy carrier – especially with a view to a more climate-friendly future. But have you ever wondered what hydrogen actually is and how it is produced? In this article, we look at the basics and technologies used to produce hydrogen and what makes hydrogen a special element.

Simply put, hydrogen is a gas that is colorless, odorless, and tasteless. It enjoys its reputation as the simplest and most abundant chemical element in the universe. Hydrogen consists of tiny particles, protons, and electrons.

It is extremely responsive and can combine with other elements to form compounds such as water. It acts as a powerful fuel and can be used to generate electricity, operate vehicles, and generate heat. As a clean energy carrier, hydrogen has the potential to reduce environmental impact and contribute to a sustainable energy supply

Several technologies for hydrogen production exist, which can be used depending on the specific requirements and available resources. Here are some common methods:
 

• Steam reforming of natural gas: This is currently the most widely used technology for hydrogen production. In this process, natural gas, which consists mainly of methane, is heated with water vapor in the presence of a catalyst. Figuratively, steam reforming can be thought of as the "breaking up" of natural gas.
  
  In this process, the methane in the natural gas reacts with the water vapor, producing hydrogen (H2) and carbon monoxide (CO). The hydrogen obtained is purified and can then be used as fuel in vehicles, to generate electricity in fuel cells or in various industrial applications. This process is inexpensive, but it also has disadvantages. Carbon dioxide is released as a by-product, which has an impact on the environment.

• Electrolysis of water: In electrolysis, water is split into hydrogen and oxygen with the help of an electric current. Equipment or equipment called electrolyzers carry out the electrolysis process to do this.

• Solar hydrogen production: In this method, solar energy is used instead of electrical energy to carry out the electrolysis process. This can be done either by direct sunlight or by concentrating solar radiation with the help of solar mirrors or collectors. This new technology could be used in countries where sufficient sun is available and make it possible to produce hydrogen particularly cost-effectively.

• Thermochemical Hydrogen Production (Biological Hydrogen Production): Some microorganisms, such as certain bacteria or algae, can produce hydrogen through fermentation or photosynthesis. This method is still under development, but has potential as a sustainable and environmentally friendly hydrogen source. However, the disadvantage of this type of production is the finite resources.

It should be noted that not all hydrogen production processes are equally sustainable or environmentally friendly. The sustainability of hydrogen production depends on the energy source used and the CO2 emissions during the production process. In order to make the most of the benefits of hydrogen as a clean energy source, it is of great importance to use renewable energy sources for the production of hydrogen.

The use of renewable energies such as solar energy, wind energy or hydropower can significantly reduce CO2 emissions in hydrogen production, making it more sustainable and sustainable. Environmentally friendly hydrogen is produced. This is an important step towards achieving a low-carbon future and tackling climate change.

Electrolysis is the process that is most promising. The electrolysis process enables the environmentally friendly production of hydrogen, especially if the electricity used for it comes from renewable energy sources. These technologies play an important role in enabling clean hydrogen to emerge as a sustainable energy carrier for various applications. We took a detailed look at the different technologies and took a look at the advantages and disadvantages of each.

PEM electrolysis, also known as proton exchange membrane electrolysis, splits water into hydrogen and oxygen using a polymer membrane and electric current.

Advantages:

• Fast start-up and quick adaptation to variable loads
• High efficiency in partial load operation
• Low operating temperature (50-80°C), reducing the use of expensive materials
• Compact size and easy integration into existing systems
• High level of technological maturity (TRL 7-8)

Disadvantages:

• Sensitive to impurities in the water, therefore requires pre-treatment of the water
• Limited service life of the PEM fuel cell (approx. 10,000 operating hours)
• Higher costs compared to alkaline electrolysis

In alkaline electrolysis, water is split into its constituents hydrogen and oxygen using an alkaline electrolyte, typically an aqueous solution of potassium hydroxide.

Advantages:

• Lower costs compared to PEM electrolysis
• Robust against contaminants in the water
• Long service life of the electrolytic cell (approx. 40,000-80,000 operating hours)
• Highest level of technological maturity (TRL 8-9)

Disadvantages:

• Slower reaction rate compared to PEM electrolysis
• Higher operating temperatures (70-100°C) lead to higher energy consumption
• More difficult integration into existing systems due to different operating parameters

SOEC stands for Solid Oxide Electrolysis Cell and refers to a high-temperature electrolytic cell that converts water into hydrogen and oxygen at high temperatures and with solid oxides as the electrolyte.

Advantages:

• High efficiency and heat recovery due to high operating temperatures (800-1000°C)
• Flexibility in the use of different fuels (e.g. steam, CO2)

Disadvantages:

• High operating temperatures require expensive materials and special thermal insulation
• Slow start and adaptation to variable loads
• Larger dimensions and complex system integration
• Little operating experience on a large scale

AEM stands for Anion Exchange Membrane and refers to an electrolyzer technology that uses a special membrane that allows permeability to negatively charged ions and splits water into hydrogen and oxygen using electric current.

Advantages:

• Lower costs compared to PEM electrolysis
• Robust against contaminants in the water
• Operation at lower temperatures (approx. 60-80°C)

Disadvantages:

• Limited development and commercialization compared to PEM and alkaline electrolysis
• Potential challenges to membrane long-term stability
• No large-scale installations available. Low level of technological maturity.