- 2072 Asoj · 6 marks
Bio-energy with an example
Short answer
Bio-energy is energy from organic matter like wood, dung, or crop residues. A common example is a household biogas plant: cattle dung mixed with water ferments in an airtight digester, producing methane for cooking and slurry for fertilizer, reducing firewood use and indoor smoke.
What is bio-energy? Describe with a suitable example.
Bio-energy is the energy obtained from biomass, i.e. organic matter from plants and animals (wood, crop residue, dung, energy crops, food and municipal organic waste). It is stored solar energy, captured by photosynthesis, and is renewable if used sustainably.
Forms of bio-energy
| Form | Process | Product |
|---|---|---|
| Solid | Direct combustion, briquetting | Heat, steam for power |
| Gaseous | Anaerobic digestion | Biogas (CH₄ + CO₂) |
| Gaseous | Gasification (partial oxidation) | Producer gas (CO, H₂) |
| Liquid | Fermentation | Bio-ethanol |
| Liquid | Transesterification | Bio-diesel (from jatropha etc.) |
Example: household biogas plant (Nepal)
Nepal has several hundred thousand family-size biogas plants (mainly GGC-2047 fixed dome design) promoted by AEPC and the Biogas Support Programme.
Dung+water -> Inlet -> Digester (dome) -> Gas pipe
| |
Outlet tank Stove / lamp
|
Slurry (fertiliser)
Working:
- Fresh cattle dung is mixed with water (about 1:1) and fed through the inlet.
- In the airtight digester, bacteria break down the organic matter without oxygen in three stages: hydrolysis, acid formation and methane formation.
- Gas (about 60% methane) collects in the dome and flows through a pipe to the stove.
- Digested slurry comes out of the outlet and is used as manure.
Benefits:
- Replaces firewood and kerosene; saves forest.
- Smoke-free kitchen and better health.
- Good organic fertiliser.
- Reduces GHG emission (registered under CDM).
Other examples
- Bagasse-based power in sugar mills.
- Rice husk gasifier for power in rice mills.
- Improved cook stoves burning firewood more efficiently.
✓ Answer checked by Claude Opus 5.5 (high effort)
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