Cofiring of Biomass with Coal
Biomass power generation is a proven, mature technology and is the single largest source of non-hydro renewable electricity. Biomass installations range from very small units of 5-10 kW capacity to large facilities 50 MW and larger in size. Commercial scale power is considered 10MW and larger.
Biomass fuel from forested areas comes from residues of non-commercial wood. Residues can be gathered during milling, logging, thinning, and other forest management activities. With a biomass plant, efficient generation of forest residues is helpful for providing sustainable fuel supplies.
Electricity produced from biomass is considered to be carbon neutral and therefore helps to combat global warming. The CO2 that the facility will release would have been produced as the plants and trees naturally decomposed in the forest without the benefit of electricity production. So, it is like harnessing energy that would otherwise be wasted, just like wind energy and solar energy. So, there is a potential advantage of reducing Green House Gas (GHG) emissions.
Biomass energy is the utilization of energy stored in organic matter. Examples of biomass include wood, leaves, animal waste, crops, bones, and scales. The abundant plant life in our planet is natures store house of solar energy and chemical resources. Whether cultivated by man, or growing wild, plant matter represents a massive quantity of a renewable resource that we call biomass. Put another way, biomass is stored solar energy that can be converted to electricity or fuel. Biomass is a renewable resource.
The other major reasons for consideration of the biomass power option are:
- Disposal of biomass residues combined with the production of electricity and heat
- Power production from abundant indigenous biomass resources
- Power for remote locations rich in biomass resources
- Pollution-free: Lower NOx, SOx, CO emissions
- No bed make-up material required
- Helps reducing unemployment in specific regions
The area requirements are not much and are comparable to Thermal power plants, if built nearby sources of rich biomass.
A variety of conversion processes are used to convert biomass to either thermal energy, liquid, solid or gaseous fuels. These processes include thermal conversion via combustion or pyrolysis (Torrefaction) , chemical conversion, microbial conversion or fermentation, and physical conversion to pellets or cubes, i.e. densified fuels. Electrical energy and heat generation is most commonly accomplished through direct combustion of biomass in a boiler. In the combustion process, energy content, moisture content and chemical composition are the most important biomass characteristics affecting combustion processes.
For a list of Biomass Co-firing power plants around the world: http://www.ieabcc.nl/database/cofiring.php