Hydrogen is an energy carrier that can be produced in many different ways. Currently, over 95% of the hydrogen produced is from fossil fuels. In order for hydrogen to be green, i.e. zero-emission, the process for its production must not emit harmful emissions into the atmosphere. The most common way to produce green hydrogen is through the process of electrolysis, in which the electric molecule separates the water molecule into its constituent parts - hydrogen and oxygen. A key role in this process is the source of electricity. For the production process to be green, the source of electricity must be renewable. Such sources of energy are wind, sun, biomass, and others.