🌱 Sources of Energy
Biomass and Biogas
Class 10 CBSE Science | NCERT + Foundation + Competitive Preparation
🌱 Sources of Energy | Biomass and Biogas
1. Introduction | परिचय
English: Biomass is organic material obtained from plants, animals and other living or recently living matter that can be used as a source of energy.
हिन्दी: Biomass या जैव-द्रव्य पौधों, पशुओं तथा अन्य जीवित या हाल ही में जीवित रहे जैविक पदार्थों से प्राप्त कार्बनिक पदार्थ है, जिसका उपयोग ऊर्जा के स्रोत के रूप में किया जा सकता है।
Examples include wood, crop residues, animal dung and other organic wastes.
उदाहरण: लकड़ी, कृषि अवशेष, पशु अपशिष्ट/गोबर तथा अन्य जैविक कचरा।
हिन्दी: Biomass या जैव-द्रव्य पौधों, पशुओं तथा अन्य जीवित या हाल ही में जीवित रहे जैविक पदार्थों से प्राप्त कार्बनिक पदार्थ है, जिसका उपयोग ऊर्जा के स्रोत के रूप में किया जा सकता है।
Examples include wood, crop residues, animal dung and other organic wastes.
उदाहरण: लकड़ी, कृषि अवशेष, पशु अपशिष्ट/गोबर तथा अन्य जैविक कचरा।
Important: Biomass can be converted into useful forms of energy such as heat, biogas, biofuels and electricity.
महत्वपूर्ण: Biomass को ऊष्मा, बायोगैस, जैव ईंधन तथा विद्युत ऊर्जा जैसे उपयोगी ऊर्जा रूपों में बदला जा सकता है।
महत्वपूर्ण: Biomass को ऊष्मा, बायोगैस, जैव ईंधन तथा विद्युत ऊर्जा जैसे उपयोगी ऊर्जा रूपों में बदला जा सकता है।
2. What is Biomass? | Biomass क्या है?
Biomass is renewable organic matter that stores chemical energy originally captured by plants through photosynthesis.
पौधे प्रकाश संश्लेषण के माध्यम से सूर्य की ऊर्जा को रासायनिक ऊर्जा के रूप में अपने जैविक पदार्थ में संचित करते हैं। यही संचित रासायनिक ऊर्जा Biomass में उपलब्ध होती है।
पौधे प्रकाश संश्लेषण के माध्यम से सूर्य की ऊर्जा को रासायनिक ऊर्जा के रूप में अपने जैविक पदार्थ में संचित करते हैं। यही संचित रासायनिक ऊर्जा Biomass में उपलब्ध होती है।
Sunlight → Photosynthesis → Chemical Energy in Biomass
3. Sources of Biomass | Biomass के स्रोत
| Source | Examples | Energy Use |
|---|---|---|
| Wood | Firewood, wood residues | Heating and cooking |
| Agricultural residues | Straw, husk, stalks | Heat, fuel, electricity |
| Animal waste | Cattle dung | Biogas production |
| Food/organic waste | Kitchen and market waste | Biogas/composting |
| Energy crops | Selected biomass crops | Bioenergy production |
4. Biomass as a Source of Energy | Biomass से ऊर्जा
Biomass can be burned directly to produce heat. It can also be converted into other fuels such as biogas or liquid biofuels.
Biomass का प्रत्यक्ष दहन करके ऊष्मा प्राप्त की जा सकती है। इसके अलावा इसे बायोगैस या तरल जैव ईंधन जैसे अन्य ऊर्जा रूपों में बदला जा सकता है।
Biomass का प्रत्यक्ष दहन करके ऊष्मा प्राप्त की जा सकती है। इसके अलावा इसे बायोगैस या तरल जैव ईंधन जैसे अन्य ऊर्जा रूपों में बदला जा सकता है।
Energy conversion:
Chemical Energy in Biomass → Heat Energy
Chemical Energy in Biomass → Biogas → Heat/Electricity
Biomass → Biofuel → Useful Energy
Chemical Energy in Biomass → Heat Energy
Chemical Energy in Biomass → Biogas → Heat/Electricity
Biomass → Biofuel → Useful Energy
5. Animated Biomass Energy Cycle | Biomass ऊर्जा चक्र
6. What is Biogas? | Biogas क्या है?
English: Biogas is a combustible gas mixture produced by the anaerobic decomposition of biodegradable organic matter by microorganisms.
हिन्दी: बायोगैस एक ज्वलनशील गैसों का मिश्रण है जो ऑक्सीजन की अनुपस्थिति में सूक्ष्मजीवों द्वारा जैव-अवक्रमणीय कार्बनिक पदार्थों के अपघटन से बनता है।
हिन्दी: बायोगैस एक ज्वलनशील गैसों का मिश्रण है जो ऑक्सीजन की अनुपस्थिति में सूक्ष्मजीवों द्वारा जैव-अवक्रमणीय कार्बनिक पदार्थों के अपघटन से बनता है।
Key Word: Anaerobic
Anaerobic means in the absence of oxygen.
Anaerobic का अर्थ है ऑक्सीजन की अनुपस्थिति में।
Anaerobic means in the absence of oxygen.
Anaerobic का अर्थ है ऑक्सीजन की अनुपस्थिति में।
7. Composition of Biogas | Biogas की संरचना
| Component | Importance |
|---|---|
| Methane (CH₄) | Main combustible component and major source of energy. |
| Carbon dioxide (CO₂) | Non-combustible component present in biogas. |
| Hydrogen sulphide (H₂S) | May be present in smaller quantities; gives characteristic odour and is corrosive/toxic at sufficient concentrations. |
| Water vapour | May also be present. |
Exam Point: Methane is the main combustible component of biogas.
परीक्षा बिंदु: Biogas का मुख्य ज्वलनशील घटक Methane (CH₄) है।
परीक्षा बिंदु: Biogas का मुख्य ज्वलनशील घटक Methane (CH₄) है।
8. Biogas Plant | Biogas संयंत्र
A biogas plant is a system in which biodegradable organic material is mixed with water and fed into an airtight digester. Microorganisms decompose the material anaerobically and produce biogas.
Biogas plant में जैव-अवक्रमणीय कार्बनिक पदार्थ को पानी के साथ मिलाकर एक बंद/वायुरुद्ध digester में डाला जाता है। सूक्ष्मजीव ऑक्सीजन की अनुपस्थिति में इसका अपघटन करते हैं और Biogas उत्पन्न होती है।
Biogas plant में जैव-अवक्रमणीय कार्बनिक पदार्थ को पानी के साथ मिलाकर एक बंद/वायुरुद्ध digester में डाला जाता है। सूक्ष्मजीव ऑक्सीजन की अनुपस्थिति में इसका अपघटन करते हैं और Biogas उत्पन्न होती है।
9. Animated Biogas Plant Diagram | Biogas Plant का एनिमेटेड चित्र
10. Working of a Biogas Plant | Biogas Plant की कार्य-विधि
-
Collection of feed material:
Cow dung and other suitable biodegradable organic matter are collected.
कच्चा पदार्थ: गोबर तथा उपयुक्त जैव-अवक्रमणीय पदार्थ एकत्र किए जाते हैं। -
Mixing:
The material is mixed with water to form a slurry.
मिश्रण: पदार्थ को पानी के साथ मिलाकर slurry बनाई जाती है। -
Digestion:
The slurry enters an airtight digester.
अपघटन: Slurry को वायुरुद्ध digester में डाला जाता है। -
Anaerobic decomposition:
Microorganisms break down organic matter in the absence of oxygen.
अवायवीय अपघटन: सूक्ष्मजीव ऑक्सीजन की अनुपस्थिति में कार्बनिक पदार्थों का अपघटन करते हैं। -
Gas formation:
Biogas containing methane is produced.
गैस निर्माण: Methane युक्त Biogas बनती है। -
Collection:
The gas is collected and supplied through pipes.
संग्रह: गैस को एकत्र करके पाइप द्वारा उपयोग के स्थान तक पहुँचाया जाता है। -
Bio-slurry:
The remaining digested material can be used as a nutrient-rich organic manure after appropriate handling.
Bio-slurry: बचा हुआ पचा हुआ पदार्थ उचित प्रबंधन के बाद जैविक खाद के रूप में उपयोग किया जा सकता है।
11. Anaerobic Decomposition | अवायवीय अपघटन
Anaerobic digestion is a biological process in which microorganisms break down biodegradable organic matter without oxygen.
अवायवीय पाचन एक जैविक प्रक्रिया है जिसमें सूक्ष्मजीव ऑक्सीजन की अनुपस्थिति में जैव-अवक्रमणीय कार्बनिक पदार्थों को तोड़ते हैं।
अवायवीय पाचन एक जैविक प्रक्रिया है जिसमें सूक्ष्मजीव ऑक्सीजन की अनुपस्थिति में जैव-अवक्रमणीय कार्बनिक पदार्थों को तोड़ते हैं।
Organic Matter
→ Anaerobic Microorganisms
→ Biogas + Digested Slurry
12. Role of Microorganisms | सूक्ष्मजीवों की भूमिका
Different groups of microorganisms participate in anaerobic digestion. The final stage includes methane-forming microorganisms, commonly called methanogens, which produce methane-rich biogas.
अवायवीय पाचन में विभिन्न प्रकार के सूक्ष्मजीव भाग लेते हैं। अंतिम चरण में methanogens जैसे methane-forming microorganisms methane-rich biogas बनाने में महत्वपूर्ण भूमिका निभाते हैं।
अवायवीय पाचन में विभिन्न प्रकार के सूक्ष्मजीव भाग लेते हैं। अंतिम चरण में methanogens जैसे methane-forming microorganisms methane-rich biogas बनाने में महत्वपूर्ण भूमिका निभाते हैं।
Remember:
Methanogens → Methane formation
Methanogens → Methane बनाने वाले सूक्ष्मजीव
Methanogens → Methane formation
Methanogens → Methane बनाने वाले सूक्ष्मजीव
13. Types of Biomass Energy Conversion
| Method | Process | Main Product |
|---|---|---|
| Direct combustion | Biomass is burned | Heat |
| Anaerobic digestion | Microbial decomposition without oxygen | Biogas |
| Fermentation | Microbial conversion of suitable biomass | Bioethanol etc. |
| Gasification | Thermochemical conversion with limited oxygen/oxidant | Producer/synthesis gas |
| Pyrolysis | Thermal decomposition with little/no oxygen | Bio-oil, gases and char |
14. Uses of Biogas | Biogas के उपयोग
- Cooking fuel
- Heating applications
- Electricity generation through suitable engines/generators
- After appropriate purification, it can be upgraded to biomethane for certain applications
- Suitable organic waste management systems
Biogas → Cooking / Heating / Electricity
बायोगैस का उपयोग खाना पकाने, ऊष्मा प्राप्त करने तथा उपयुक्त जनरेटर/इंजन द्वारा बिजली बनाने में किया जा सकता है।
बायोगैस का उपयोग खाना पकाने, ऊष्मा प्राप्त करने तथा उपयुक्त जनरेटर/इंजन द्वारा बिजली बनाने में किया जा सकता है।
15. Bio-slurry | जैव-स्लरी
The material left after anaerobic digestion is called digestate or bio-slurry. It contains nutrients and organic matter and can be used as an organic soil amendment/manure after appropriate treatment and management.
Anaerobic digestion के बाद बचा पदार्थ digestate या bio-slurry कहलाता है। इसमें पोषक तत्व और कार्बनिक पदार्थ होते हैं और उचित उपचार एवं प्रबंधन के बाद इसे जैविक खाद/मृदा सुधारक के रूप में उपयोग किया जा सकता है।
Anaerobic digestion के बाद बचा पदार्थ digestate या bio-slurry कहलाता है। इसमें पोषक तत्व और कार्बनिक पदार्थ होते हैं और उचित उपचार एवं प्रबंधन के बाद इसे जैविक खाद/मृदा सुधारक के रूप में उपयोग किया जा सकता है।
16. Advantages of Biomass and Biogas | लाभ
Biomass Advantages:
- Renewable when sustainably managed.
- Uses agricultural and organic residues.
- Can provide heat, fuels and electricity.
- Can reduce dependence on some fossil fuels.
- Converts biodegradable waste into useful fuel.
- Produces methane-rich combustible gas.
- Useful for cooking and electricity generation.
- Produces digestate that can be used as organic manure after appropriate management.
- Can support better organic waste management.
17. Limitations | सीमाएँ
- Biomass collection and transportation can be costly.
- Burning biomass directly can produce smoke and air pollutants if combustion is incomplete or poorly controlled.
- Sustainable biomass supply is important to avoid pressure on forests and land.
- Biogas production requires suitable feedstock and operating conditions.
- Biogas plants require proper maintenance and gas handling.
- Biogas production can vary with temperature, feedstock composition and digester conditions.
- Methane leakage should be minimized because methane is a potent greenhouse gas.
18. Biomass vs Biogas | अंतर
| Biomass | Biogas |
|---|---|
| Organic material used as an energy resource. | Combustible gas produced from anaerobic digestion. |
| Examples: wood, crop residues, dung. | Main combustible component: methane. |
| Can be directly burned or converted. | Produced through microbial digestion. |
| May exist as solid organic material. | Gaseous fuel. |
19. Biogas vs LPG
| Biogas | LPG |
|---|---|
| Produced from biodegradable organic matter. | Commercial fuel mainly consisting of propane/butane mixtures. |
| Renewable when feedstock is sustainably replenished. | Derived primarily from fossil-fuel processing. |
| Methane is the main combustible component. | Propane and butane are major combustible components. |
| Can be produced locally in a biogas plant. | Usually supplied through cylinders or pipelines. |
20. Biomass and Fossil Fuels
Biomass can be renewable on a human timescale when the biological resources are replenished sustainably. Coal, petroleum and natural gas are fossil fuels formed over geological timescales and are considered non-renewable.
Biomass भी तभी वास्तव में टिकाऊ renewable resource बनती है जब उसका उपयोग और पुनःउत्पादन संतुलित तथा sustainable हो।
Biomass भी तभी वास्तव में टिकाऊ renewable resource बनती है जब उसका उपयोग और पुनःउत्पादन संतुलित तथा sustainable हो।
21. Environmental Importance | पर्यावरणीय महत्व
Properly managed biogas systems can help capture useful energy from organic waste instead of allowing uncontrolled decomposition. They can also produce a useful digestate.
उचित तरीके से प्रबंधित Biogas systems जैविक कचरे से उपयोगी ऊर्जा प्राप्त करने में मदद कर सकते हैं तथा बची हुई slurry/digestate को उचित प्रबंधन के बाद जैविक खाद के रूप में उपयोग किया जा सकता है।
उचित तरीके से प्रबंधित Biogas systems जैविक कचरे से उपयोगी ऊर्जा प्राप्त करने में मदद कर सकते हैं तथा बची हुई slurry/digestate को उचित प्रबंधन के बाद जैविक खाद के रूप में उपयोग किया जा सकता है।
Important: Biomass is not automatically carbon-neutral or environmentally harmless. Its environmental impact depends on the source, land use, harvesting, transportation, processing and combustion technology.
22. 30 MCQs | बहुविकल्पीय प्रश्न
1. Biomass is mainly:
A. Organic material from biological sources
B. Nuclear fuel
C. Mineral ore only
D. Artificial radiation
Answer: A
2. The main combustible component of biogas is:
A. Oxygen
B. Methane
C. Nitrogen
D. Carbon dioxide
Answer: B
3. Biogas is mainly produced by:
A. Photosynthesis
B. Combustion in air
C. Anaerobic digestion
D. Nuclear fission
Answer: C
4. Anaerobic means:
A. At high temperature
B. Under sunlight
C. In water only
D. In the absence of oxygen
Answer: D
5. Which is commonly used as feedstock for a biogas plant?
A. Cattle dung
B. Iron ore
C. Glass
D. Sand
Answer: A
6. Methanogens are microorganisms associated with the production of:
A. Oxygen
B. Methane
C. Iron
D. Nitrogen
Answer: B
7. Which gas is non-combustible and commonly present in biogas?
A. Methane
B. Hydrogen
C. Carbon dioxide
D. Oxygen
Answer: C
8. The mixture fed into a typical biogas digester is called:
A. Alloy
B. Ore
C. Emulsion
D. Slurry
Answer: D
9. Biomass stores mainly:
A. Chemical energy
B. Nuclear energy
C. Magnetic energy
D. Sound energy
Answer: A
10. Plants initially capture solar energy through:
A. Respiration
B. Photosynthesis
C. Fermentation
D. Anaerobic digestion
Answer: B
11. Which is an example of biomass?
A. Uranium
B. Natural gas
C. Crop residue
D. Iron
Answer: C
12. Which process occurs inside an anaerobic digester?
A. Nuclear fission
B. Electrolysis only
C. Photosynthesis
D. Microbial decomposition
Answer: D
13. Which product remains after anaerobic digestion?
A. Digestate or bio-slurry
B. Uranium
C. Pure oxygen
D. Iron powder
Answer: A
14. Biogas can be used for:
A. Cooking
B. Heating
C. Electricity generation
D. All of these
Answer: D
15. Which statement about methane is correct?
A. It is the main combustible component of biogas
B. It is completely non-combustible
C. It is the main solid component
D. It is an oxide of carbon
Answer: A
16. Which is NOT normally a biomass source?
A. Wood residue
B. Crop residue
C. Animal dung
D. Uranium ore
Answer: D
17. The digester of a biogas plant should generally be:
A. Open to continuous oxygen supply
B. Airtight
C. Filled with sand
D. Made of dry wood only
Answer: B
18. The main purpose of mixing dung with water is to form:
A. Slurry
B. Alloy
C. Cement
D. Metal
Answer: A
19. Biogas production is a biological process involving:
A. Only metals
B. Microorganisms
C. Electric motors only
D. Magnets only
Answer: B
20. Which gas gives biogas its main fuel value?
A. Carbon dioxide
B. Oxygen
C. Methane
D. Nitrogen
Answer: C
21. Which process converts biomass into biogas?
A. Anaerobic digestion
B. Reflection
C. Refraction
D. Distillation only
Answer: A
22. Bio-slurry can be useful as:
A. Nuclear fuel
B. Organic manure/soil amendment
C. Metal ore
D. Semiconductor
Answer: B
23. Which energy source is directly associated with organic matter?
A. Biomass
B. Uranium
C. Geothermal steam only
D. Tidal energy only
Answer: A
24. Which condition is essential for anaerobic digestion?
A. Continuous sunlight
B. High oxygen concentration
C. Absence of oxygen
D. Vacuum only
Answer: C
25. Which component may be present in biogas and has a characteristic odour?
A. H₂S
B. O₂
C. Pure H₂
D. Neon
Answer: A
26. Which is a limitation of direct biomass burning?
A. It can cause smoke and air pollution if poorly controlled
B. It never produces heat
C. Biomass cannot burn
D. It requires uranium
Answer: A
27. Biogas is primarily a:
A. Liquid metal
B. Combustible gas mixture
C. Solid mineral
D. Nuclear fuel
Answer: B
28. Which of the following can be converted into biogas?
A. Suitable biodegradable organic waste
B. Glass bottles
C. Aluminium sheets
D. Sand
Answer: A
29. Sustainable biomass management is important because:
A. Biomass resources can never be depleted
B. Unsustainable harvesting can harm ecosystems
C. Biomass contains no carbon
D. Biomass is a mineral
Answer: B
30. The correct sequence for a typical biogas plant is:
A. Dung + water → digester → anaerobic digestion → biogas
B. Coal → turbine → sunlight → biogas
C. Water → transformer → methane → plant
D. Oxygen → photosynthesis → LPG → digester
Answer: A
23. 30 Subjective Questions with Answers
2 Marks
Q1. What is biomass?
Biomass is organic material obtained from plants, animals and other biological sources that can be used as an energy resource.
2 Marks
Q2. Give two examples of biomass.
Wood and agricultural residues are examples of biomass. Animal dung and organic waste are other examples.
2 Marks
Q3. What is biogas?
Biogas is a combustible gas mixture produced by anaerobic microbial decomposition of biodegradable organic matter.
2 Marks
Q4. Name the main combustible component of biogas.
Methane (CH₄) is the main combustible component of biogas.
2 Marks
Q5. What is meant by anaerobic digestion?
It is the microbial breakdown of biodegradable organic matter in the absence of oxygen.
3 Marks
Q6. Why is biomass considered a renewable energy source?
Biomass can be renewed through plant growth and biological processes when the resources are managed sustainably. However, unsustainable harvesting can make biomass use environmentally damaging.
3 Marks
Q7. What is the role of methanogens?
Methanogens are methane-forming microorganisms that participate in the anaerobic digestion process and help produce methane-rich biogas.
3 Marks
Q8. Why is a biogas digester kept airtight?
The digester is kept airtight to maintain anaerobic conditions, which are necessary for the microorganisms involved in methane production.
3 Marks
Q9. Mention three uses of biogas.
Biogas can be used for cooking, heating and electricity generation using suitable engines/generators.
3 Marks
Q10. What happens to the material left after biogas production?
The remaining digestate or bio-slurry contains nutrients and organic matter. After appropriate handling, it can be used as organic manure or a soil amendment.
3 Marks
Q11. What is the function of the mixing tank?
The mixing tank mixes organic feedstock such as cattle dung with water to form a slurry that can be fed into the digester.
3 Marks
Q12. Why is methane important in biogas?
Methane is combustible and therefore provides most of the useful fuel value of biogas.
4 Marks
Q13. Explain the working of a biogas plant.
Organic material is mixed with water and fed into an airtight digester. Microorganisms decompose it anaerobically. Methane-rich biogas accumulates and is collected through a pipe. The remaining digestate is removed and can be used as manure after suitable management.
4 Marks
Q14. Explain the composition of biogas.
Biogas mainly contains methane and carbon dioxide. Smaller quantities of gases such as hydrogen sulphide and water vapour may also be present. Methane provides the major combustible value.
4 Marks
Q15. Explain why biogas is considered a useful waste-management technology.
Biogas plants process biodegradable organic waste under controlled anaerobic conditions. They recover useful energy as methane-rich gas and produce digestate that can be used beneficially after appropriate management.
4 Marks
Q16. Differentiate between aerobic and anaerobic decomposition.
Aerobic decomposition occurs in the presence of oxygen, whereas anaerobic decomposition occurs without oxygen. Biogas production uses anaerobic digestion and produces methane-rich gas.
4 Marks
Q17. What are the advantages of biomass energy?
Biomass is potentially renewable, can use agricultural residues and organic wastes, and can provide heat, fuels and electricity. It can also reduce dependence on some fossil fuels when sustainably managed.
4 Marks
Q18. What are the limitations of biomass energy?
Collection and transport may be difficult, direct combustion can produce pollutants if poorly controlled, and unsustainable harvesting can harm forests, soil and biodiversity. Biomass availability can also vary by season and region.
5 Marks
Q19. Draw and explain a biogas plant.
A basic biogas plant includes a mixing tank, inlet, airtight digester, gas collection space/pipe, outlet and digestate collection area. Dung and water form slurry, which undergoes anaerobic digestion in the digester. Methane-rich biogas is collected for use and the remaining digestate exits through the outlet.
5 Marks
Q20. Explain the complete process of biogas formation.
Biodegradable organic material is mixed with water and introduced into an airtight digester. Microorganisms break down complex organic matter through several stages. Methane-forming microorganisms finally produce methane-rich biogas. The gas is collected and the remaining digestate is removed.
5 Marks
Q21. Explain the environmental benefits of a properly managed biogas plant.
It can convert organic waste into useful fuel, reduce uncontrolled decomposition of waste, produce digestate for beneficial use and provide a renewable source of energy. Methane leakage and digestate management must still be properly controlled.
5 Marks
Q22. Compare biomass and biogas.
Biomass refers to organic biological material used as an energy resource. Biogas is a gaseous fuel produced when suitable biodegradable biomass undergoes anaerobic digestion. Biomass can be solid, while biogas is a gas mixture mainly containing methane and carbon dioxide.
5 Marks
Q23. Compare biogas and LPG.
Biogas is mainly methane-rich gas produced biologically from organic matter. LPG is a commercial fossil-derived fuel mainly containing propane and butane. Both can be used for cooking, but their sources and composition differ.
6 Marks
Q24. Explain biomass as an energy source with suitable examples.
Biomass consists of organic material such as wood, crop residues, animal dung and organic wastes. Plants capture solar energy through photosynthesis and store it as chemical energy. Biomass can be burned directly for heat or converted into biogas, biofuels or electricity. Sustainable management is essential.
6 Marks
Q25. Explain why methane is called the energy-rich component of biogas.
Methane is a combustible hydrocarbon. When methane burns in oxygen, chemical energy is released mainly as heat. Since methane forms the major combustible part of biogas, it gives biogas its useful fuel value.
6 Marks
Q26. Explain the role of microorganisms in a biogas plant.
Microorganisms break down biodegradable organic matter under anaerobic conditions. Different microbial groups participate in successive stages of digestion. Methanogens are especially important in the final methane-forming stage and produce methane-rich biogas.
6 Marks
Q27. Explain how biomass can be converted into different forms of energy.
Biomass can be directly burned to produce heat. Through anaerobic digestion it can produce biogas. Through fermentation it can produce fuels such as bioethanol from suitable feedstocks. Thermochemical processes such as gasification and pyrolysis can produce gases, liquids and solid products.
6 Marks
Q28. Explain the advantages and limitations of biogas.
Advantages: renewable when feedstock is sustainably supplied, converts organic waste into useful fuel, can be used for cooking/heating/electricity, and produces digestate.
Limitations: requires suitable feedstock, digester management, temperature and process control; gas leakage and hydrogen sulphide need proper management.
Limitations: requires suitable feedstock, digester management, temperature and process control; gas leakage and hydrogen sulphide need proper management.
6 Marks
Q29. Why should biomass energy be used sustainably?
If biomass is harvested faster than it can regenerate, forests, soil, biodiversity and carbon stocks can be damaged. Sustainable sourcing ensures that biomass remains a renewable resource while limiting environmental impacts.
6 Marks
Q30. Write an exam-ready note on Biomass and Biogas.
Biomass is organic matter from plants, animals and other biological sources that can be used for energy. It contains chemical energy originally captured by plants through photosynthesis. Biogas is a methane-rich combustible gas produced by anaerobic digestion of biodegradable organic matter. A biogas plant contains a mixing system, airtight digester, gas collection system and digestate outlet. Biogas is useful for cooking, heating and electricity generation, while digestate can be used as organic manure after proper management.
24. Assertion–Reason Questions
Q1. Assertion: Biogas is produced under anaerobic conditions.
Reason: Methanogens involved in biogas formation require oxygen-free conditions.
Reason: Methanogens involved in biogas formation require oxygen-free conditions.
Answer: Both Assertion and Reason are true, and the Reason correctly explains the Assertion.
Q2. Assertion: Methane gives biogas its main fuel value.
Reason: Methane is a combustible gas.
Reason: Methane is a combustible gas.
Answer: Both are true, and the Reason correctly explains the Assertion.
Q3. Assertion: Carbon dioxide is the main combustible component of biogas.
Reason: Carbon dioxide supports burning.
Reason: Carbon dioxide supports burning.
Answer: Both Assertion and Reason are false.
Q4. Assertion: Bio-slurry can be useful as organic manure.
Reason: It contains nutrients and organic matter after digestion.
Reason: It contains nutrients and organic matter after digestion.
Answer: Both are true, and the Reason correctly explains the Assertion.
Q5. Assertion: A biogas plant should be kept continuously open to air.
Reason: Anaerobic microorganisms require oxygen for methane formation.
Reason: Anaerobic microorganisms require oxygen for methane formation.
Answer: Both Assertion and Reason are false.
25. HOTS / Competency-Based Questions
HOTS 1: Why is cow dung mixed with water before feeding it into a biogas plant?
It helps form a pumpable slurry that can move through the digester and provides a suitable medium for microbial digestion.
HOTS 2: Why does a biogas plant not simply burn the dung directly?
Anaerobic digestion converts organic matter into methane-rich gas, which can be collected and used as a cleaner and convenient fuel. It also leaves a useful digestate.
HOTS 3: Why is oxygen undesirable inside the anaerobic digester?
The process depends on microorganisms operating under oxygen-free conditions. Excess oxygen disrupts the anaerobic environment required for methane formation.
HOTS 4: A village has abundant cattle dung but no reliable LPG supply. How can a biogas plant help?
The dung can be processed anaerobically to produce methane-rich biogas for cooking. The remaining digestate can also be used as organic manure after appropriate management.
HOTS 5: Why should methane leakage from biogas plants be minimized?
Methane is a strong greenhouse gas. Preventing leakage improves the climate benefit of the system and also ensures that more of the produced fuel is actually used.
26. Golden Points | परीक्षा के लिए महत्वपूर्ण बिंदु
- Biomass = organic biological material used as an energy resource.
- Plants store solar energy as chemical energy through photosynthesis.
- Biomass can be burned directly or converted into fuels.
- Biogas is produced by anaerobic digestion.
- Anaerobic = absence of oxygen.
- Methane (CH₄) is the main combustible component of biogas.
- Carbon dioxide is another major component of biogas.
- Methanogens help produce methane.
- Biogas plant requires an airtight digester.
- Dung + water → slurry.
- Organic slurry → anaerobic digestion → biogas + digestate.
- Biogas can be used for cooking, heating and electricity generation.
- Bio-slurry/digestate can be useful as organic manure after proper management.
- Sustainable biomass management is essential.
- Methane leakage should be minimized.
27. One-Minute Revision | एक मिनट में Revision
🌱 Biomass
↓
🦠 Anaerobic Digestion ↓
🔥 Methane-rich Biogas ↓
🍳 Cooking / ⚡ Electricity
🦠 Anaerobic Digestion ↓
🔥 Methane-rich Biogas ↓
🍳 Cooking / ⚡ Electricity
Biomass: Organic material
Biogas: Combustible gas mixture
Main fuel: Methane
Process: Anaerobic digestion
Important microbes: Methanogens
Feed: Organic waste / dung
Output: Biogas + digestate
Main use: Cooking / heating / electricity
Biogas: Combustible gas mixture
Main fuel: Methane
Process: Anaerobic digestion
Important microbes: Methanogens
Feed: Organic waste / dung
Output: Biogas + digestate
Main use: Cooking / heating / electricity
28. Concept Map | अवधारणा मानचित्र
29. Final Summary | अंतिम सारांश
Biomass is organic material obtained from biological sources and can be used as a renewable energy resource when managed sustainably. Plants capture solar energy through photosynthesis and store it as chemical energy.
Biogas is a methane-rich combustible gas produced by anaerobic digestion of biodegradable organic matter. A typical biogas plant uses a mixing tank, airtight digester, gas collection system and digestate outlet.
Biogas can be used for cooking, heating and electricity generation. The remaining digestate can provide useful nutrients and organic matter for soil after proper management.
Biomass → Anaerobic Digestion → Biogas → Useful Energy
परीक्षा के लिए सबसे महत्वपूर्ण शब्द हैं: Biomass, Anaerobic Digestion, Methane, Methanogens, Biogas Plant, Slurry, Digestate और Renewable Energy.
Biogas is a methane-rich combustible gas produced by anaerobic digestion of biodegradable organic matter. A typical biogas plant uses a mixing tank, airtight digester, gas collection system and digestate outlet.
Biogas can be used for cooking, heating and electricity generation. The remaining digestate can provide useful nutrients and organic matter for soil after proper management.
Biomass → Anaerobic Digestion → Biogas → Useful Energy
परीक्षा के लिए सबसे महत्वपूर्ण शब्द हैं: Biomass, Anaerobic Digestion, Methane, Methanogens, Biogas Plant, Slurry, Digestate और Renewable Energy.
📘 Class 10 CBSE Science
Sources of Energy | Biomass and Biogas
NCERT + Foundation + Competitive Preparation
Sources of Energy | Biomass and Biogas
NCERT + Foundation + Competitive Preparation
