An overview of renewable hydrogen production

Abstract

Hydrogen is a fuel that can generate heat, energy and be used as a raw material, however, its main production methods use non-renewable sources (natural gas, oil and steam reforming) that damage the environment. Its versatility as a fuel outlines it as a viable energy vector, so it is important to identify and prioritize sustainable production methods that use renewable sources. This document discusses six technologies that produce hydrogen through water, biomass and renewable sources. The splitting of water molecules is a process used in four important methods: electrolysis, thermolysis, photocatalysis, and sonolysis. Electrolysis uses cells in which electrical energy is applied to a pair of electrodes to split molecules. Thermolysis is a process that uses heat, rather than electrical energy, to perform such separation. Photocatalysis converts solar energy into chemical energy on a solid semiconductor material used as a catalyst. Finally, sonolysis uses ultrasonic frequencies to force water to split. Biomass is also used to produce hydrogen. The dark fermentation method uses reactors where microorganisms, substrate and inoculum react to produce the fuel. While the biocatalysis method uses photonic energy and photosensitive microorganisms. Electrolysis is the method with the best performance in hydrogen production, this technology has had the greatest development with equipment on the market producing 1 kg of fuel for every 47.5 kWh fed to the electrolytic cell. The application of the hydrogen focuses on supplying the petrochemical and chemical industry with raw material for production and treatment processes. However, by 2050, hydrogen is expected to be used in means of transport to mobilize automotive vehicles, maritime vessels and aircraft. That is why the correct production methods must be used for such an energy system.