Biogas is a combustible fuel which is produced through the anaerobic digestion process. Anaerobic means “in the absence of oxygen”. In the right set of circumstances, the organic fraction of liquid or solid biomass is converted into valuable fuel. Biogas consists of roughly 40% – 70% methane, with the rest being CO2 and trace amounts of H2O, H2S, H2 and NH3 produced by the microbiological process. The amount of methane in the biogas is largely a function of the organic input menu.
Liquid and solid manure, vegetable waste, grocery store waste, fats, oils, and greases (FOG), slaughterhouse waste, and selective energy crops, like corn, are ideally suited as inputs to a biogas plant. Biogas, when utilized in a combined heat and power (CHP) unit produces electrical energy for sale and heat energy for use locally. The heat produced by the CHP is used to heat the digestion process to improve biogas yield. Biogas can also be cleaned up for injection into the local natural gas grid or as a vehicle fuel.
The remaining byproduct of the digestion process is digestate which is a fermented organic material which may be used as high quality fertilizer. Biogas has a key role in supporting a diverse energy portfolio as a flexible, dispatchable fuel source.
Anaerobic digestion of livestock manure and organic food residuals provides security to the agricultural/ food sector. Several benefits include:
– financial diversification and risk mitigation through energy sales
– implementing strong nutrient management practices
– supporting local processing of agricultural production
– reducing commercial fertilizer requirements and costs
The green economy benefits of biogas are considerable and include:
– local job creation in technical, manufacturing and construction/trades
– economic development generating billions of dollars of investment in rural communities
– creation of useful by-products from wastes, acting as a significant economic multiplier
As a source of renewable energy, biogas has unique characteristics and offers many energy end uses. Biogas can
– generate reliable, flexible power 24/7
– manage intermittent renewable power supply through means of storage and flexible power
– improve/support local infrastructure and power quality
– upgrade to renewable natural gas (RNG) for injection into the natural gas grid, delivering ‘green’ renewable energy through existing infrastructure
– be compressed for use as transportation fuel, or direct replacement of fossil-sourced natural gas in household heating, or industrial, commercial and institutional processes
The environmental benefits of biogas are numerous.
– control weed seed germination, reducing herbicide use
– remove odour-causing compounds
– capture and use of methane, a greenhouse gas 21 times worse than CO2
– convert high energy waste streams into fuel, diverting them from landfill