Tag: meaning and type of resources

Biogas typically refers to a mixture of different gases produced by the breakdown of organic matter in the absence of oxygen. Biogas can be produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste or food waste. It is a renewable energy source.
Biogas can be produced by anaerobic digestion with anaerobic bacteria, which digest material inside a closed system, or fermentation of biodegradable materials.

Anaerobic digestion is a natural process in which bacteria convert organic materials into biogas. It occurs in marshes and wetlands and in the digestive tract of ruminants. The bacteria are also active in landfills, where they are the principal process degrading landfilled food wastes and other 
biomass. Biogas can be collected and used as a potential energy resource. The process occurs in an anaerobic (oxygen-free) environment through the activities of acid- and methane-forming (methanogenic) bacteria that break down the organic material and produce methane and carbon dioxide in a gaseous form, known as biogas. 

Solar energy is inexhaustible non-conventional resource. Its use is yet to pick up because of requirement of back up system to store and generate electricity during night and during cloudy days. There are three methods of harnessing solar energy- direct heating (e.g., solar cookers), thermoelectric conversion or solar thermal power plants, e.g., steam generation and photovoltaic conversion.

Renewable source of energy include biomass energy and some forms of inexhaustible energy like solar energy, hydropower, wind power, tidal energy, wave energy, geothermal energy etc. 

Coal and oil are fossil fuels been derived from dead bodies of plants and animals, which existed in past. Hence, they are carbon compounds and emit carbon dioxide on combustion. Organic compounds are obviously compounds of carbon and will evolve carbon dioxide on combustion. Nuclear energy is non conventional, non renewable resource. Nuclear fission (now fusion also) of selected radioactive materials yields large amount of heat energy. For example one amu of Uranium - 235 yields energy equal to burning of 15 metric tonnes of coal. The energy released in nuclear fission and fusion is not due to combustion process and hence, does not evolves carbon dioxide.