Biogas is a type of biofuel that is naturally produced from the decomposition of organic waste. When organic matter, such as food scraps and animal waste, break down in an anaerobic environment (an environment absent of oxygen) they release a blend of gases, primarily methane and carbon dioxide. Because this decomposition happens in an anaerobic environment, the process of producing biogas is also known as anaerobic digestion.
Anaerobic digestion is a natural form of waste-to-energy that uses the process of fermentation to breakdown organic matter. Animal manure, food scraps, wastewater, and sewage are all examples of organic matter that can produce biogas by anaerobic digestion. Due to the high content of biogas (typically 50-75%) biogas is combustible, and therefore produces a deep blue flame, and can be used as an energy source.
Biogas is known as an environmentally-friendly energy source because it alleviates two major environmental problems simultaneously:
- The global waste epidemic that releases dangerous levels of methane gas every day
- The reliance on fossil fuel energy to meet global energy demand
By converting organic waste into energy, biogas is utilizing nature’s elegant tendency to recycle substances into productive resources. Biogas generation recovers waste materials that would otherwise pollute landfills; prevents the use of toxic chemicals in sewage treatment plants, and saves money, energy, and material by treating waste on-site.
Biogas takes a problematic gas, and converts it into a much safer form. More specifically, the methane content present in decomposing waste is converted into carbon dioxide. Methane gas has approximately 20 to 30 times the heat-trapping capabilities of carbon dioxide. This means that when a rotting loaf of bread converts into biogas, the loaf’s environmental impact will be about 10 times less potent than if it was left to rot in a landfill.
In India, the estimate for the production of biogas is about 20,757 lakh cubic meters in 2014-15. This is equivalent to 6.6 crore domestic LPG cylinders. This is equivalent to 5% of the total LPG consumption in the country today.
Apart from these, under the twelfth five year plan (2012-2017), the government of India had set a target to set up 6.5 lakh biogas plants across the nation with a budget of Rs. 650 crore under a program called, the National Biogas and Manure Management Program (NBMMP). It had been estimated that by setting up of these biogas plants, about 1-6 cubic meter of biogas per day and 4745 lakh cubic meter biogas could be produced annually. The program is being implemented by the State Nodal Departments/State Nodal Agencies and Khadi and Village Industries Commission (KVIC), Biogas Development and Training Centers (BDTCs).
A wood-burning stove (or wood burner or log burner) is a heating appliance capable of burning wood fuel and wood-derived biomassfuel, such as wood pellets. Generally the appliance consists of a solid metal (usually cast iron or steel) closed fire chamber, a fire brick base and an adjustable air control.
The stove is connected by ventilating stove pipes to a suitable chimney or flue, which will fill with hot combustion gases once the fuel is ignited. The chimney or flue gases must be hotter than the outside temperature to ensure combustion gases are drawn out of the fire chamber and up the chimney. Many wood-burning stoves are engineered such that they can be converted to multi-fuel stoves with the addition of a grate.