biogaasi

Biogaasi, or biogas, is a renewable energy produced through anaerobic digestion of organic matter by specialized bacteria in oxygen-free conditions. It is primarily a mixture of methane and carbon dioxide, with smaller amounts of hydrogen sulfide, water vapor, and trace gases. The gas can be burned directly for heat and light or upgraded for injection into natural gas networks or use as vehicle fuel.

Biogas is produced from a wide range of feedstocks, including animal manure, agricultural residues, food waste, sewage sludge, and other organic waste streams. In a biogas plant, the feedstock is decomposed in a digester, a sealed tank that maintains anaerobic conditions. The biological process proceeds through stages of hydrolysis, acidogenesis, acetogenesis, and methanogenesis, yielding a stable gasblend and a nutrient-rich digestate.

Typical biogas contains roughly 50–70 percent methane, with the remainder mainly carbon dioxide; small quantities of hydrogen sulfide and moisture vary with feedstock and operation. The energy content depends on the gas composition and humidity, but biogas is commonly used on-site for cooking, heating, or electricity generation, and can be upgraded to biomethane suitable for natural gas networks or as a transport fuel.

Advantages of biogas include waste management, reduction of greenhouse gas emissions from organic waste, local energy production, and the production of digestate that can be used as fertilizer. Disadvantages can include odor, potential hydrogen sulfide corrosion, methane leakage risks, high upfront costs for digester systems, and the need for consistent feedstock and maintenance. Digesters come in several designs, such as fixed-dome, floating-drum, and plug-flow, with scale ranging from household to industrial plants.

Globally, biogas is most prominent in rural and agricultural communities where waste streams are abundant and energy access is limited, with ongoing expansion in both developing and some developed regions.