Biomass Definition (Energy Source)
Although biomass is a term that is closely associated with ecology, it can also be defined and described in terms of energy. The biomass energy is one of the primary sources of energy for many activities. It is considered as the source of renewable energy since the primary source of this energy is plenty in this world. Most biomass comprises carbon, hydrogen, oxygen, nitrogen, and other alkali metals, which provide a large amount of energy when burnt. Organic materials like agricultural wastes, wood, and municipal wastes can be recycled for the production of biofuels.
Definition of Biomass in terms of energy
Definition of Biomass could be, the energy that is generated from biomass is called biomass energy. All organic matter that can produce energy when reactions are done with it can produce biomass energy. These can be wood, leaves, pellets, fecal wastes, and other organic matters. Technically speaking, biomass energy was discovered back during the ages when humans used to live in caves. Marco Polo, in the 13th century, described the use of biomass for the production of fuel after taking inspiration from the Chinese who used to cover sewage tanks to generate biogas.
Biomass energy can be both renewable and non-renewable. The first source of energy in the production of biomass is the sun. The plants convert solar energy by photosynthesis into chemical energy as food and subsequently uses it in their growth, which is later converted to fuel. The energy derived from biomass can be processed directly by burning to produce heat, or converted directly into electricity, or can also be processed to produce biofuels in an indirect manner.
Plants that are a rich source of Biomass energy and hence considered for Biofuel production
There are several plants that can be considered as a rich source of biomass energy and hence are often considered for the production of biofuels. Some of them include wheat, switchgrass, sunflower, cottonseed, mustard oil, corn, canola, sugarcane, soy plants, jatropha, palm oil, and many more. These plants are often cultivated in large fields for the production of biofuels.
Ways to produce Biomass energy- Thermal conversion
One of the primitive ways of producing biomass energy is to burn the organic material and utilize the heat energy produced from it. The thermal conversion of biomass involves heating the feedstock so that energy is released, the feedstock is dehydrated, or the biomass is stabilized. The common source of biomass feedstock is the municipal solid wastes and also waste from lumber mills and paper factories.
The different processes of thermal conversion are direct firing, pyrolysis, co-firing, gasification, as well as anaerobic decomposition. Before the biomass is burnt, they are needed to be dried. The chemical process of drying biomasses is called torrefaction. In this process, the biomass is heated to a temperature of 200 to 320ᴼC. The biomass not only loses all its moisture, and also loses the ability to absorb it. After torrefaction, the biomass is converted into a black dry material, which is then compressed to form briquettes. Briquettes are highly hydrophobic, thus enabling them to be kept in moist places. Also, the briquettes have high energy density and can easily be burnt by direct firing or co-firing.
Ways to produce Biomass energy- Biofuel
Biomass is considered a renewable source of biofuels like biodiesel and ethanol. Such biofuels are used to power vehicles and machines in several countries like Austria, Sweden, and the United States of America. Ethanol is produced by the fermentation process of biomasses that are rich in carbohydrates, such as corn, wheat, and sugarcane. Biodiesel can be made by combining this ethanol with animal fat, vegetable oil, and recycled cooking fat.
Biofuels do not produce as much energy and, therefore, not as effective as gasoline. However, they can be mixed with gasoline, and this mixture can be used to power automobiles and pieces of machinery used in several industries. By using such mixture, the emission of harmful gases, as observed in the case of fossil fuels, is greatly minimized.
Ways to produce Biomass energy- Biochar
Biochar is a byproduct of the pyrolysis process of biomasses. It is considered to be a valuable source of energy for agriculture and other environmental uses.
When biomass rots or burns, it releases large amounts of carbon dioxide and methane into the atmosphere. However, such emissions are prevented, and the process of charring these biomasses can retain the carbon content. When these biochars are added back to the soil, they can still absorb carbon from the surroundings. They can act as sequestered carbon sinks, which is beneficial for maintaining the quality of the soil it has been found that addition of biochars to the soil helps in increasing the quality and quantity of agricultural production.
Ways to produce Biomass energy- Black liquor
Black liquor is a toxic byproduct in the production of paper from wood. Till the 1930s, this black liquor is considered as an industrial waste product and was dumped into the nearby water bodies. However, later it was found that the black liquor can retain almost 50% of the carbon content of the source material. Later it was used as a power source in several mills with the help of the recovery boiler. It was also tried to be gasified so that it can be used to generate electricity.
Ways to produce Biomass energy- Hydrogen fuel cells
Hydrogen fuel cells are produced from biomass that is rich in hydrogen. These hydrogen atoms are chemically extracted from the biomasses and are used in batteries for generating powers and fuel machines and vehicles. These cells are mainly used for automobiles driven in remote locations, like wilderness areas or in spacecraft. Hydrogen fuel cells can be considered as an alternative source of energy for vehicles. In current times, these cells are used as a source of power for boats, buses, submarines, and forklifts. Testings are going on for their usage in airplanes as well.
Conclusion
All living organisms can be considered as a rich source of energy. Most of our energy sources are carbon, hydrogen, and oxygen, and all these atoms make up the carbohydrate, which is an integral part of all living organisms. Biomass can be converted to different forms of energy, which can then be used in different ways like as fuel for automobiles, as a source of power for different industries, and to generate electricity.
FAQs on Biomass Energy
1. What exactly is biomass energy and how is it generated?
Biomass energy is a form of renewable energy derived from organic material known as biomass. This organic matter, which includes plants, wood, and waste, contains stored chemical energy from the sun through photosynthesis. Energy is generated from biomass through several methods, including direct combustion (burning) to produce heat, thermal conversion like pyrolysis to create biofuels, or biochemical processes like anaerobic digestion to produce biogas.
2. What are five common examples of biomass used for energy?
Biomass sources are varied and abundant. Five common examples include:
- Wood and Wood Waste: This includes everything from forest debris and lumber mill scraps to dedicated energy crops like poplar trees.
- Agricultural Crops and Residues: Materials like corn stover, wheat straw, sugarcane, and switchgrass are frequently used.
- Animal Manure: Waste from livestock farms can be placed in digesters to produce biogas (methane).
- Municipal Solid Waste (MSW): The organic components of household and industrial trash, such as paper, food scraps, and yard waste, can be burned to generate electricity.
- Algae: Certain species of algae are cultivated for their high oil content, which can be converted into biodiesel.
3. How are biofuels like ethanol and biodiesel produced from biomass?
Biofuels are transportation fuels derived from biomass. Ethanol is typically produced through the fermentation of biomass rich in carbohydrates, such as sugarcane or corn. Yeast consumes the sugars and converts them into alcohol. Biodiesel is created by chemically reacting vegetable oils, animal fats, or recycled cooking grease with an alcohol. This process, known as transesterification, produces biodiesel and a byproduct called glycerin.
4. What is the key difference between thermal conversion processes like pyrolysis and gasification?
The main difference lies in the presence of oxygen. Pyrolysis is the process of heating biomass to high temperatures in the complete absence of oxygen. This breaks down the organic material into bio-oil, syngas, and a solid residue called biochar. In contrast, gasification involves heating biomass with a limited amount of oxygen, which is not enough for full combustion. This process primarily converts the biomass into a combustible gas mixture called syngas (synthesis gas).
5. Is biomass energy a truly renewable resource?
Biomass is considered renewable because its source—plants—can be regrown in a relatively short period. However, its renewability depends on sustainable management. If biomass resources, like forests, are consumed faster than they are replenished, it effectively becomes a non-renewable source. True sustainability requires a balance where the rate of biomass harvesting does not exceed the rate of its regrowth, preventing deforestation and soil depletion.
6. What are the main advantages and disadvantages of using biomass as an energy source?
Using biomass energy offers several benefits but also has significant drawbacks.
- Advantages: It is a widely available, renewable resource that helps reduce landfill waste. It is often considered carbon neutral because the carbon released during combustion is offset by the carbon absorbed by the plants during their growth.
- Disadvantages: It can lead to deforestation if not managed sustainably. Growing energy crops requires significant land and water, potentially competing with food production. The combustion of biomass can also release air pollutants like nitrogen oxides and particulate matter.
7. Why isn't biomass energy considered a completely 'clean' or zero-emission fuel?
While biomass is often called carbon neutral, it is not a zero-emission fuel. The combustion process itself releases pollutants into the atmosphere, including carbon dioxide (CO2), nitrogen oxides (NOx), volatile organic compounds (VOCs), and particulate matter. Although the CO2 released was recently captured from the atmosphere by the plant, the other emissions contribute to air pollution and smog, unlike zero-emission sources like solar or wind power at the point of generation.
8. What is biochar and why is it beneficial for the environment?
Biochar is a stable, charcoal-like substance that is produced as a byproduct when biomass undergoes pyrolysis (heating without oxygen). It has significant environmental benefits. When added to soil, biochar can improve soil fertility, increase water retention, and reduce the need for chemical fertilisers. Most importantly, it acts as a method of carbon sequestration, locking carbon into the soil for hundreds or even thousands of years, thereby helping to mitigate climate change.
9. How does biomass energy compare to other renewable sources like solar or wind?
Biomass has a key advantage over solar and wind energy: it is dispatchable. This means it can be stored and used to generate power on demand, 24/7, providing a stable and reliable energy supply. In contrast, solar and wind are intermittent, as they only generate power when the sun is shining or the wind is blowing. However, biomass requires a constant supply of physical fuel, utilises more land, and produces emissions during combustion, whereas solar and wind have zero operational emissions.
