Biogas is created by the breakdown of organic matter and primarily consists of methane (CH4) and carbon dioxide (CO2). Biogas can be used as a cooking fuel, to power vehicles and in the case of ZooShare, to produce electricity.
To make biogas, you need a biogas plant (also known as a biodigester) to provide the oxygen-free environment for a process known as anaerobic digestion: The biogas plant works like a big concrete stomach, mixing organic waste on a continual basis. Meanwhile, bacteria eat and digest the waste, releasing methane as well as other gases. Instead of letting these greenhouse gases escape into the atmosphere (where they contribute to global warming), the biogas plant captures the gas and stores it until it can be used to create electricity. The biogas plant is “fed” organic waste on a continual basis, meaning it can store biogas and produce electricity at any time.
The biogas is fed directly from a holding tank into a combustion engine. This generates both electricity and heat. The electricity is used to supply homes and businesses. The heat and power required for operating the biogas plant is produced within this system.
At the end of the biogas production process there are two forms of waste. The liquid waste is known as digestate and this is rich in nutrients. This can be bottled and used as a liquid fertiliser. By returning this to food producing systems we are one step closer to a circular economy.
The solid waste has a variety of uses. It can be used as a soil amendment and is rich in nutrients. It can also serve as animal bedding or a raw material for the manufacture of paper products.
The production of biogas:
• Diverts organic waste from landfills
• Recycles a readily available source of energy
• Stops methane (21x worse than CO2) from going into the atmosphere
• Stores its own energy, meaning it can dispatch electricity whenever it’s needed
• Eliminates pathogens and odours in organic waste
• Returns valuable nutrients to the soil in the form of a rich fertilizer