a business opportunity for farmers
Article by Tarik Höppener
B
iogas is a gas composition that contains mainly
methane (CH4) (50 75%) and carbon dioxide
(CO2) (25 - 50%) with further minor components like moisture
(H2O), nitrogen (N), oxygen (O2),
hydrogen (H2), hydrogen sulphide
(H2S) as well as traces of other impurities created through a microbiological degradation process in the
absence of oxygen. The process
refers to anaerobic digestion which
naturally occurs in human and animal stomachs and/or in swamps.
The composition of the gas varies
according to the initial organic material brought into the process and
the technical and environmental
circumstances of the degradation
process.
What can be done with biogas?
Biogas is a renewable energy. The
production process requires bio-
mass as an input source, which
differentiates it from other sources
of renewable energies such as photovoltaic (PV), concentrated solar
power (CSP), and wind power. Biogas is also classified as bioenergy
or bio-fuel such as biodiesel or bioethanol. The word fuel implies the
characteristics of energy commodities such as petrol, diesel, natural
gas or also coal and a wide range
of energy uses such as power generation, compressed biomethane
(CNG) for usage in vehicles, bottled
cylinders for retail (CNG or LNG), or
fuel substitution in commercial and
industrial processes. These characteristics also apply to biogas, with
the capability of energy storage for
demand oriented consumption.
This is probably the most distinct
characteristic of biogas compared
to other renewables.
Where is biogas positioned in the
economic value chain?
Biogas belongs in the energy sector
but there are also strong links to
other economic sectors. Its formation naturally or commercially
always needs biomass, which requires linkages to commercial sectors from where it can possibly be
sourced. The value chain around
biogas starts with any sort of agricultural activity as the largest contributor to commercial biomass
formation. The produced biomass
is mostly used in the agropossessing industry with the purpose of supplying food. Some proportion of the food supply does
not find its way into people’s stomachs and at some stage needs to
be disposed of in a cost effective
manner in landfill sites. For instance with maize products, only
the grain is taken into the agro