Aim: This article attempts to present the issues related to the search for alternatives to energy resources in all sectors of the economy. The direction of the search is to choose “green energy” (in this case hydrogen), which, due to its potential wide application, is already beginning to be treated as an instrument of carbon neutrality. Most EU countries have agreed that they will be carbon-neutral by 2050, which should result in the reduction of greenhouse gas emissions to the atmosphere by around 95% compared to the beginning of the gas emissions calculation in 1990. However, achieving emission neutrality will require a far-reaching elimination of emissions not only in the power sector, but also in other sectors (including industry, transport and heating). These areas still rely on emission fossil fuels (coal, crude oil and natural gas), which cannot be directly replaced with electricity from RES. Introduction: Hydrogen is not a source of energy, but it is a very effective carrier. Although it is practically not in the free state, it is very often found in the form of chemical compounds such as CH4 (methane) or H2O (water). In order to extract the energy it contains, it must be isolated from the molecules it is composed of. Hydrogen can be transported via gas pipelines (gaseous) or tankers (liquefied). It is currently used in the petrochemical industry, in - cluding for oil refining and chemical industry for the production of fertilizers, ammonia or methanol. Recently, hydrogen has become a topic that is often discussed in the public space in the context of climate protection (and thus decarbonisation of the economy). This fuel is credited with extraordinary potential and applicability in so many areas that it should be widely regarded as oil of the 21st century and a key element of the new energy policy. Moreover, the investment in hydrogen should support sustainable growth and job creation, which will be critical when recovering from the COVID-19 pandemic. Methodology: The article provides an overview of research questions and the most recent results of considerations. It presents a multidimensional and interdisciplinary analysis of the suitability of alternative fuels and the implementation of the related projects. The analysis of the topic was based on, among others, on the project of the Polish Hydrogen Strategy, which is important for the further development of research topics and cooperation in this field. Conclusions: For the energy sector that processes available forms of energy, hydrogen is probably a good choice for the future. It can be an alternative to natural gas in providing backup capacity for renewable energy sources that produce energy dependent on weather conditions (i.e. sun and wind). Hy- drogen, which has the advantage of high energy density, is also a good tool for storing renewable energy and for transmitting and distributing renewable energy over long distances. Due to this, green energy from regions of the world with high insolation and wind energy, such as Australia, Latin America or North Africa, could be transferred over long distances (taking into account losses in energy networks it would be a much more economical solution). It would not require high-cost investments in new infrastructure. The article deals with the aspects relating to all parts of the value chain – production, transmission, storage and use of hydrogen, taking into account the legal conditions at the national (Polish Hydrogen Strategy) and the EU level, and proposing sustainable support systems and measurable goals. Keywords: green hydrogen, synthetic fuel, renewable energy, solar fuel, hydrogen Article type: review article
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