**4. Conclusions**

Hydrogen energy technologies cannot be used in the industry due to the high production cost, storage difficulties, and transportation costs in today's conditions. However, the fact that hydrogen can be used directly without air pollutants or greenhouse gas emissions and can be produced from low-carbon energy sources are the main reasons for the widespread preference for hydrogen. Clean energy is used to limit air pollution and global warming, especially where the climate crisis has come to the fore in global markets. Various countries and companies see hydrogen as an important clean energy resource that is likely to play a role in the future of the energy sector.

Hydrogen: is a resource that proposes methods that can provide decarbonization in sectors where it is difficult to reduce emissions such as transportation, petrochemistry, and iron and steel. In addition, hydrogen can help improve air quality and

#### *Introductory Chapter: Hydrogen Energy DOI: http://dx.doi.org/10.5772/intechopen.108635*

increase energy security. Thanks to hydrogen, some technologies can produce, store, transport, and use energy in different routines. Hydrogen, which can be transported in liquid form by pipelines, tankers, and ships, can be converted into electricity and methane, used as energy for households or manufacturing sectors, or as fuel for cars, trucks, ships, and airplanes.

Hydrogen is increasingly forming the basis of mainstream energy debates all over the world. In recent years, many experts have been investigating the potential of using this source to produce, transport, and store hydrogen from various sources and to provide an emission-free final energy supply.
