Being colorless, odorless, tasteless and transparent, hydrogen is the lightest element in the universe. Hydrogen is an important element for achieving a carbon-free future. Thus, hydrogen is valued in clean energy systems as an "energy of the future" and an effective tool for long-term energy storage.
Hydrogen has more energy capacity (about three times more than gasoline) than any other fuel by weight, but less energy capacity (about four times less than gasoline) by volume. However, the fact that hydrogen is not a pure element in nature and is in the form of compounds makes it difficult to use this source in terms of energy. Hydrogen can be used as an energy or fuel source from a variety of sources, including water, biomass and other fuels.
Hydrogen is a type of pure combustible fuel. During the combustion of hydrogen, only water vapor is formed as a by-product and during this process, heat and electricity are produced. The potential of hydrogen is highly valued in climate change mitigation measures. Hydrogen energy has the ability to replace conventional fuels in marine, air transport and certain industrial processes, where the decarbonization process is more complex. Currently, hydrogen is not widely used as a fuel. Thus, in terms of efficiency and sustainability, there is a need for improvements in this area and the application of modern technology.
Types of hydrogen
Hydrogen is produced directly from fuel, biomass or by electrolysis of water. At present, hydrogen is produced mainly using natural gas. In general, due to the diversity of the production process, hydrogen is divided into the following types:
Brown Hydrogen (Black Hydrogen): Obtained by gasification of coal and carbon dioxide is released into the atmosphere during the production process. It is sometimes called as black hydrogen.
Gray hydrogen: Obtained from natural gas. Because of being the cheapest type of hydrogen, it is widespread.
Blue hydrogen: Produced by natural gas. In this process, the application of Carbon Capture, Usage and Storage technologies (CCUS) prevents the release of some or all of CO2 emissions into the atmosphere.
Green hydrogen: It is the most environmentally friendly type of hydrogen. Using electricity from renewable energy sources, it is obtained from the electrolysis decomposition of water. The production of green hydrogen is more expensive than other types. However, the reduction in the cost of electrolyzers in the future will also reduce the cost of producing green hydrogen.
Purple (red, pink) hydrogen: Purple hydrogen is produced by electrolyzing water using nuclear energy. CO2 emission is not generated during this process, but this method is not considered to be completely environmentally friendly.
The technology by which hydrogen is produced from a variety of energy sources, then stored for use, transported via pipelines, and after that converted into heat and electricity is called the "hydrogen economy" of the future. Hydrogen is currently being tested in all sectors of the world (electricity, heating and cooling for buildings and households; industry; transport; raw material production, etc.), including energy production, storage and distribution. For this purpose, the countries all over the world have put forward goals and plans related to their energy strategies.
European Union countries are significantly increasing their investment in green energy technologies, as well as hydrogen, to achieve the goals of the transition to green energy. In international practice, various tariff policies and tools are applied for short and medium term in order to increase economic activity in this area. In recent years, the production and use of hydrogen has been identified as one of the solutions which will make a significant contribution to the energy transition process in the long term.