BIOGAS

WASTE DIVERTING, LOW-CARBON ENERGY SOURCE

Turning organic waste into a gas, diverting waste from landfills or waterways, can help cut carbon emissions, while creating value from wasted resources.

Biodigesting waste organics into gas

Biodigesters process organic waste to produce a combustible gas that can be used for electricity generation and/or heating technologies. Biomass can be converted to gas by biological processes such as anaerobic digestion or gasification, which is a thermochemical process.

In anaerobic digestion, biogas is produced from the fermentation of organic matter or feedstock. Feedstock can be wet organic material such as manure, sewage sludge, industrial effluents, and agricultural and forest residues. Biogas from anaerobic digesters is composed primarily of methane, which can be used as a fuel or chemical feedstock.

Gasification is a thermochemical process that occurs when biomass is heated in an oxygen-starved environment (containing approximately 1/3 of the air needed for complete combustion) to produce a synthetic gas (i.e. “syngas”), which contains carbon monoxide and hydrogen. Any reasonably dry biomass can be converted to syngas, which can also be used as a fuel or chemical feedstock.

Benefits

PROCESS DIVERTS ORGANIC WASTE FROM LANDFILLS

Organic waste streams that would otherwise end up in landfills are used as feedstocks in biogas systems, thereby reducing the amount of organic waste to be handled.

REDUCTION IN METHANE EMISSIONS

Organic wastes (especially from sewage streams) are a source of methane emissions which contributes to global warming. By treating these wastes and using them as energy sources, GHG emissions are reduced.

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VALUABLE BYPRODUCTS

Biogas processing can produce valuable byproducts such as fertilizers that can be commercialized.

POTENTIAL TO INTEGRATE WITH EXISTING GAS NETWORK

Depending on the size of your biogas plant and quality of biogas you produce, you could benefit from integrating into a pre-existing natural gas distribution network.

Considerations

ECONOMIC VIABILITY

The biogas technology works well for large scale projects but is not yet at a stage where it is economically viable to implement at a small scale.

FEEDSTOCK AVAILABILITY

The biogas treatment process requires a continuous feedstock stream of organic waste or sewage and is hence scalable only where there is regular availability.

DEBATABLE TECHNOLOGY AND COMMERCIAL READINESS

Even though the biogas technology is sustainable and provides a less carbon-intensive alternative, economic viability of the technology is yet to be widely accepted.