Biomass is a term defined to describe a variety of energy derived products from photosynthesis. This technology includes all plant material such as trees, crops, seaweed, and animal wastes. All forms of biomass contain sunlight energy stored in chemical bonds. By the process of photosynthesis plants use solar energy to transfer CO2 and H20 into glucose (carbohydrates). The strong covalent bonds between the carbons, oxygen and hydrogen of the glucose molecule are stored as potential energy. The breaking of the bonds by digestion, burning or decomposition releases the stored energy. 9
Biomass in the form of wood has been traditionally man’s oldest form of energy. Sequestering of this energy has been by the process of burning to produce heat and cooking. Historically, as industrialization and energy needs increased biomass reserves were depleted.
Large wood burning stoves are used to heat a large area or generate electricity. Techniques include burning chips of wood or sometimes the tree itself in a mammoth sized boiler. Other systems heat biomass in the absences of oxygen extracting flammable gasses which can be used as an alternative renewable fuel replacing fossil fuels.
Another common form of biomass energy is the burning of municipal solid wastes. Waste-to-energy power plants operate like a traditional coal plant except garbage is burned to produce steam to turn a turbine to generate electricity. Some of these plants burn raw trash, others convert it into dried pellets called
refuse derived fuel
. Sludge from treatment plants can also be incinerated from energy in the same way.
Garbage sites may not be appealing to humans but are feeding grounds to bacteria. These bacterial species slowly digest the organic matter found in the wastes while emitting their own waste products. Their methane gas product is colleted. The burning of this gas can be used similar to fossil fuel use. 9
Major crops such as corn and wheat can be used to generate liquid fuels such as methanol and ethanol. These are relatively high cost fuels to produce but when combining 10 % of ethanol to 90% gasoline Gashol is produced. Gashol is much more cost competitive and can be used in a traditional gasoline engine. It has a higher octane rating than gasoline and is also cleaner burning.
Biomass is a versatile local energy source. Those that live in wooded areas can tap a constant supply of wood while high urban areas can relish in the constant waste production. High yielding quick growing crops can be used to make fuels while providing new jobs for farmers, foresters and loggers around the country. However, burning of wood, alcohol or dried sewage creates the same set of air pollutants as fossil fuels. Over harvesting of wood causes erosion, and silting to our steams and destruction of habitats for plants and animals. Most of these problems can be manage requiring appropriate regulation, which are not yet in place.8