Biogas as a reproducible energy source: Its steam reforming for electricity generation and for farm machine fuel

The use of biogas as an energy source reduces the chance of possible emission of two greenhouse gases, CH4 and CO2, into the atmosphere at the same time. Its nature of being a reproducible energy source makes its use even more attractive. There exist two ways of using biogas as an energy source: (1) as a natural gas substitute, to burn it in a boiler or in a stove to obtain heat or to supply it to a gas engine for power generation, and (2) to steam-reform it, to obtain hydrogen for fuel cell power generation or to obtain syngas (CO + H2) from which dimethylether is synthesized to be used as diesel fuel substitute for farm machines. The former way of utilization has been commonly employed worldwide. In this article, we present the latter way that involves steam reforming of biogas for its further use as an energy source. Necessary processes involved for this way of utilization are outlined, from steam reforming of biogas to the production of hydrogen or dimethylether. The chemical uniqueness of the biogas as a feedstock for steam reforming was identified, along with the difficulties to be overcome for its practical implementation.