It is generally accepted that the transition to renewable energy sources will significantly reduce CO2 emissions. But energy is not the only one that has this effect. The metallurgical industry, transport and housing and communal services increase greenhouse gases level in the atmosphere. According to an approach to decarbonization, that it is enough to conduct a unified state policy in the field of regulation. But the introduction of special tax regimes, direct bans and restrictions on carbon-intensive technologies and processes significantly increase costs. This way is not eligible, because it does not take into account industry specifics and does not offer technological solutions. To carry out a full-fledged decabronization of the economy, it is necessary to create complex solutions. At the same time, mutual integration of infrastructures and the possibility of their coordinated management optimize work and make it more efficient.
This can be realized with the only "carbon-free" energy carrier hydrogen. Technologies for production, storage and transportation of hydrogen have already been created. In the 19th century Jules Verne wrote in his novel "The Mysterious Island": "Yes, my friends, I believe that water will one day be used as fuel, that hydrogen and oxygen which constitute it, used isolated or together, will provide an inexhaustible source of heat and light, of an intensity that coal is not capable." Hydrogen has the largest energy reserve per unit mass. When it is released and interacts with oxygen, it can turn into pure water. Further, hydrogen is obtained from water by electrolysis again. Thus, the water cycle creates carbon-neutral energy.