Biomass is the biological component obtained from living organisms. It is also referred as plant based material when energy is produced from biomass. At the same time, biomass is also applicable for both animal and vegetable resultant components.
Biomass is a renewable energy source and it can re-grow quite quickly. Sun's energy is captured by plants' chlorophyll through the photosynthesis process. Here, carbohydrates are created by converting carbon dioxide from the air and water from the ground. They are complex combination of carbon, hydrogen and oxygen.
Basically, plant materials are either broken down by micro-organisms or burned. After burning, carbohydrates are transformed into carbon dioxide and water and release the energy harnessed from the sun. This process is known as the carbon cycle in the earth. In this technique, biomass works like natural battery in order to store solar energy. Appropriate utilization of biomass can enhance the longevity of this natural battery as well as provide low-carbon energy sources. Sustainable low-carbon biomass is great source of new renewable energy which is environmentally friendly indeed.
Types of beneficial biomass
There are following types of beneficial biomass in this planet:
- Wood and forest residues which are harvested in sustainable way.
- Crop residues like wheat straw.
- Energy crops which don’t compete with food crops for land.
- Clean industrial and municipal wastes.
Typically, beneficial biomass sources help to maintain and increase the stocks of carbon stored in plants or soil. It also moves emissions from fossil fuels, like coal, natural gas and oil. Most sustainable and effective biomass resources may be varied from region to region. It also depends on the types of final application you wish to use. For example, you can utilize biomass as bio power, bio products, heat and biofuel.
Benefits of biomass
Typically, biomass offers environmental, economic and energy security benefits.
- Biomass energy decreases air pollution and net carbon emissions.
- It contributes to protect the quality of soil, maintain wildlife habitat and avoid erosion.
- Biomass helps to minimize the dependency on importing fossil fuels which reduces our expenses.
- Rapid growth of biomass energy technology helps farmers and forest owners to obtain valuable new markets for their new energy crops, forest and crops residues.
- It contributes to minimize the global warming.
How to convert biomass into electricity
Generating heat energy by burning biomass is one of the most familiar method since long time. This biomass fired heat can produce steam power for generating electricity. Burning biomass in conventional boilers provides environmental and air-quality benefits over burning fossil fuels.
Recent researches by researchers indicate that biomass can be converted more cleanly into liquid fuels. For example, producing combustible gases from gaseous process. It decreases different kinds of emissions from biomass combustion.
Technologies which can convert renewable biomass fuels into heat and electricity is called biopower technologies. It follows same process wherein fossil fuels are used to generate electricity. The energy is stored in biomass. It can be released to produce biopower by using three methods. They are – Direct Combustion, Decomposing by Anaerobic Bacteria and conversion to gas/liquid fuel.
Direct combustion
Direct combustion is one of the most used methods for generating electricity from biomass. In this method, high-pressure steam is produced by burning biomass. This steam flows over a series of turbine blades and help them to rotate. The rotation of the turbine drives a generator for generating electricity. In an existing power plant furnace wherein a portion of coals are used for generating electricity, there biomass can be used as substitute by co-firing process. Co-firing is combusting two different types of materials at the same time.
Decomposing by anaerobic bacteria
Organic waste material animal dung or human sewage, is collected in oxygen-free tanks called digesters. Some organic waste materials like cow dung, human sewage etc. are reserved in oxygen-free tanks called digesters and decomposed by anaerobic bacteria. It produces methane and other byproducts to form a renewable natural gas. After purifying, it is used for generating electricity.
Converting biomass into to a gas or liquid fuel
By using gasification and pyrolysis process, biomass can be converted to a gaseous or liquid fuel. In the gasification process, synthesis gas or syngas is produced by exposing solid biomass material to high temperatures with very small amount of oxygen present. Synthesis gas or syngas is a mixture that consists mostly of carbon monoxide and hydrogen. This gas is burnt in a conventional boiler for generating electricity. In a combined-cycle gas turbine, it can also be used as a replacement of natural gas.
In the process of pyrolysis, crude bio-oil can be produced by heating biomass in the complete absence of oxygen at a lower temperature range. This bio-oil can be used in the power plant as a substitute wherein diesel or fuel oil is used for generating electricity.