The most important and urgent global environmental problem at present is rising surface temperature from increasing greenhouse gases and the association with climate change. In the last decades Hydrogen has been touted as a wonder green fuel from transport, electricity to heating and other uses. But some energy experts argued for a long time that it is very expensive and there are available other more efficient and cheaper clean energy options. In a recent editorial (16.11.2022) in the prestigious journal Nature, they argued that “Overhyping Hydrogen as a fuel risks endangering net-zero goals”. The News feature in the same journal analysed the arguments and recent scientific facts about hydrogen production and use. [Nature News Feature, 16/11/2022 , Castelvecchi D. How the hydrogen revolution can help save the planet — and how it can’t. Many researchers see a huge role for the gas in decarbonizing economies. https://www.nature.com/articles/d41586-022-03699-0 ]. Scientists suggested long time ago that only renewable energy sources without CO2 emissions will play a key role in the decarbonization of global energy systems in the coming decades. At present renewable energy sources are on the rapid increase but there are still many questions of how rapidly is global production of renewable energy changing and what other technologies look most promising in transforming global energy mix, for electricity, heating and transport. Already, most renewables are now cheaper compared to conventional sources (fossils), and generate 3x times more jobs than fossil fuels. Renewable energy source means energy that is sustainable and low or no-emissions. Numerous studies in the last decade compared the pros and cons of various new fuel candidates. Among all the fuels considered, Hydrogen gas (H2) stands out as the best. Hydrogen is versatile with many unique and desirable properties as “clean” energy source. Hydrogen is currently used mainly in the chemical industry for the production of ammonia (NH3) and methanol (CH3OH). Hydrogen global production has so far been dominated by fossil fuels, with the steam reforming of CH4 as the main production method with CO2 emissions. The “green” hydrogen is produced mainly by electrolysis of water, which is very expensive and need expensive storage and transport methods. This review describes the current technologies for H2 production from both fossil and renewable resources. Nowadays, 50% of H2 is mainly produced by the steam reforming of CH4 process. The countries of the European Union are leading the global resurgence of Hydrogen as a future energy carrier. For energy technologists and climate experts, “green” or “renewable” Hydrogen from the electrolysis of water powered by solar photovoltaic panels or electricity surplus from wind turbines, is considered indispensable to reducing CO2 emissions and climate neutrality. “Green” Hydrogen features as a crucial solution in all 8 of the European Commission’s net zero emissions scenarios for 2050. Despite the most recent large-scale projects and facilities in many parts of the world for Hydrogen production and gigawatt-scale ambitions of many green-hydrogen developers, the Hydrogen industry is still in its infancy. China, South Korea, USA and big international companies of gases and chemical are very interested in financing pilot projects for green: hydrogen production.