Hydrogen production through renewable and non-renewable energy processes and their impact on climate change

The urbanization and increase in the human population has significantly influenced the global energy demands. The utilization of non-renewable fossil fuel-based energy infrastructure involves air pollution, global warming due to CO₂ emissions, greenhouse gas emissions, acid rains, diminishing energy resources, and environmental degradation leading to climate change due to global warming. These factors demand the exploration of alternative energy sources based on renewable sources. Hydrogen, an efficient energy carrier, has emerged as an alternative fuel to meet energy demands and green hydrogen production with zero carbon emission has gained scientific attraction in recent years. This review is focused on the production of hydrogen from renewable sources such as biomass, solar, wind, geothermal, and algae and conventional non-renewable sources including natural gas, coal, nuclear and thermochemical processes. Moreover, the cost analysis for hydrogen production from each source of energy is discussed. Finally, the impact of these hydrogen production processes on the environment and their implications are summarized.