Biomass is energy derived from vegetative matter — plants, considered with biogas as biofuels or bioenergy. Globally, bioenergy for electricity generation has reached an installed capacity of 35GW. The US alone has 500 biomass-powered power plants with an installed capacity of 7GW (IEA, 2010) (Source: Climate change, disasters and electricity generation. By Dr. Frauke Urban and Dr. Tom Mitchell Strengthening Climate Resilience Discussion Paper 8).
It can be debatable, as to whether it is a sustainable energy or not, because unless trees are grown for this purpose, we cannot continue to use trees and plants for energy. Also, burning surely does produce gasses that are all forms of particulate matter in the air, raising talk about air pollution. An example is the high methane gas it gives off, which is not good for the ozone layer. On a positive note, it does not have as many harmful emissions as Fossil Fuels, and plants, together with animal waste used in this way will reduce the amount of waste that ends up in the landfill.
Many biomass plants use crop and forest residue like perennial grasses, straw, corn stalks, rice husks, and leftover soya bean plants to produce energy. Some producers also cultivate fast-growing trees like poplars to feed the biomass plant.
Like fossil fuels, the primary source of energy from biomass is the sun. Trees and plants use sunlight to produce energy, and in their lifetime, they store the food in the form of chemical energy. As plants die (or trees are cut down), they can be used in a number of ways.
BURNING
The residue can be burned in a bunker to produce great heat that can be used to turn turbines to generate electricity.
METHANE
The residue may also be forced to decompose by the addition of some bacteria. As decomposition goes on, methane gas is produced and can be captured by special machines. Methane can be used to turn turbines too.
FERMENTATION
Crops and plants with high levels of sugar, such as sugarcane can be fermented with the help of enzymes to produce fuels like ethanol. Ethanol is becoming a popular fuel type in the automobile industry.
Biomass is not entirely a new technology — people all over the world use wood and plant residue to make fire or charcoal for cooking and heating purposes. In the United States, biomass is very common, used in many homes and especially on farms. It is estimated that about 39 million tons of crop residue go unused each year. This can be collected and put to good use.
Biomass accounts for over 10% of global primary energy supply and is the world’s fourth-largest source of energy (following oil, coal, and natural gas). Source: Renewables 2013, Global Status Report