Biogas Digester Jeff Rohrer APES March 19, 2012

How it works? Anaerobic digestion- absence of oxygen, aka fermentation Organic waste is put in a air tight chamber to keep oxygen from entering Plant, animal and fecal matter typical Methane, Carbon dioxide, Hydrogen sulphide formed

Advantages/Disadvantages Lessen global climate change NO2 changes into CO2 310 less effect on climate Reduces waste Rural creation of reusable energy, higher S of L Saves money, resources Not as clean as natural gas Methane has greater effect on climate change Contamitive gases can hurt engines Limited production, not controllable

Environmental Impacts Methane is 20 times more potent of a GHG than CO2 Release VOCs contributing to photochemical smog Methane CH4 50–75, Carbon dioxide CO2 25–50, Nitrogen N2 0–10, Hydrogen H2 ,0–1 Hydrogen sulfide H2S 0–3 ,Oxygen O2 0–0

Where it is used? What does it replace? Typically used for cooking, electricity generation and heating Can be cleaned and brought up to natural gas standards when it becomes biomethane Can replace up to 17% of vehicle fuel Used all over the world, especially in rural farming areas such as Germany (largest producer) Small scale digesters, USA (1% of natural gas use), UK, China

Future Biogas transportation Biogas train in Sweden since 2006 Biogas buses used in Europe Matter is compressed and used in transportation Injection into the natural gas grid