Biomass is a collective term that refers to all materials derived from plants and animals. Humans have been using Biomass as fuel since the time they discovered fire and burnt wood for warmth, protection and cooking. Wood still remains the most commonly used Bio fuel source today, although many other sources of Biomass – crop waste, forest waste, food crops, poultry litter and straw to name a few – exist.
Why should I be aware of this?
Biomass is a very versatile fuel, and may be used to produce heat, electricity or a combination of both. It is a source of renewable energy, as plants that make Biomass may be grown over and over again.
The UK has some of the largest examples of the use of Biomass to generate electricity in Europe.
All about Biomass
Energy from Biomass can potentially reduce greenhouse gases. Although while burning, Biomass and fossil fuels release similar quantities of carbon dioxide into the atmosphere, Biomass absorbs an equal quantity of carbon dioxide in its living form. Fossil fuels might have also done the same millennia ago, but that is too long ago to count.
Liquid Bio Fuels produced from Biomass, like Bio Diesel may enable us to reduce our dependence on petroleum and diesel, as they are the only renewable liquid transportation fuels available.
By using Biomass to derive energy, waste from landfills, farms and industries gets utilized. Thus, Biomass energy is essentially energy from easily available waste. For example, it is estimated that California produces over 60 million tonnes of dry biomass annually. If all of it were to be used, upto 2,000 megawatts of electricity could be generated, enough to power about two million homes!
Forms of Biomass
- Wood is the most commonly used Biomass energy source in the world. On a large scale, it may be used to generate energy using different techniques. First, through combustion chambers (where the material is burnt to produce steam). Second, by a process known as gasification (where the material is heated in such a way that Bio gases are given off). Third, by another process, Pyrolysis (where the material is heated in the absence of oxygen to produce an oil-like liquid, charcoal and gas).
Upon burning, wood releases a substantial amount of Carbon Dioxide into the atmosphere. However, this carbon Dioxide may be offset by replacing the felled trees with new ones. There are some sustainable wood sources too, like forest residues, tree surgery waste, wood chips, compressed saw dust and other wood residue.
- Agricultural Waste -- By products of farming and animal husbandry – for example crop residues, straw and wet organic matter (slurry), are also important sources of Biomass energy. While dry wastes – straw, crop waste etc may be burnt to produce energy, wet wastes like organic slurry can be put into Methane Digesters in anaerobic conditions to produce Methane. This gas can fuel gas engines which produce power as well as heat.
Both Methane Digesters and combustions have been found to be viable when they are close to the source of Biomass.
Some forms of Municipal and Industrial Waste may also be described as Biomass –for example, waste food, kitchen wastes, wood from construction sites etc. As sources of Biomass energy, these are not very popular yet. However, energy generated by these sources has the dual advantage of minimizing landfill space and creating cheap energy. On the flip side, these may often release harmful gases and residues which are difficult to control.
Other uses of Biomass
Recent research has shown that it is possible to use Biomass to produce many compounds like plastics, glues, antifreeze, artificial sweeteners and gels, using a process similar to the one needed to produce Biofuels.
When Biomass is heated with a small amount of oxygen, it releases carbon monoxide and hydrogen, among other compounds. These are important components plastics and acids. These may be used to make photographic films, textiles, and synthetic fabrics.
When Biomass is heated in the absence of oxygen in the process of Pyrolysis, the resultant compound is pyrolysis oil. Phenol may be extracted from this oil, which is used to manufacture wood adhesives, molded plastic, and foam insulation.