🌬️ Sources of Energy
Wind Energy and Wind Power Plants
Class 10 CBSE Science | NCERT + Foundation + Competitive Preparation
🌬️ Sources of Energy | Wind Energy and Wind Power Plants
1. Introduction | परिचय
English: Wind energy is the kinetic energy possessed by moving air. It is a renewable source of energy because wind is continuously produced by natural processes in the atmosphere.
हिन्दी: पवन ऊर्जा (Wind Energy) गतिशील वायु में उपस्थित गतिज ऊर्जा है। यह ऊर्जा का एक नवीकरणीय स्रोत है क्योंकि वायुमंडलीय प्राकृतिक प्रक्रियाओं के कारण हवा लगातार चलती रहती है।
हिन्दी: पवन ऊर्जा (Wind Energy) गतिशील वायु में उपस्थित गतिज ऊर्जा है। यह ऊर्जा का एक नवीकरणीय स्रोत है क्योंकि वायुमंडलीय प्राकृतिक प्रक्रियाओं के कारण हवा लगातार चलती रहती है।
Key Idea: Wind → Mechanical rotation of turbine → Generator → Electrical Energy
मुख्य विचार: हवा → टरबाइन का घूर्णन → जनरेटर → विद्युत ऊर्जा
मुख्य विचार: हवा → टरबाइन का घूर्णन → जनरेटर → विद्युत ऊर्जा
2. What is Wind? | पवन क्या है?
English: Wind is the large-scale movement of air from a region of relatively higher atmospheric pressure towards a region of relatively lower atmospheric pressure.
हिन्दी: वायु का अपेक्षाकृत अधिक वायुदाब वाले क्षेत्र से कम वायुदाब वाले क्षेत्र की ओर बड़े पैमाने पर प्रवाह पवन (Wind) कहलाता है।
हिन्दी: वायु का अपेक्षाकृत अधिक वायुदाब वाले क्षेत्र से कम वायुदाब वाले क्षेत्र की ओर बड़े पैमाने पर प्रवाह पवन (Wind) कहलाता है।
Unequal heating of the Earth's surface by the Sun produces differences in temperature and atmospheric pressure. These pressure differences contribute to the movement of air.
सूर्य द्वारा पृथ्वी की सतह को असमान रूप से गर्म करने से तापमान और वायुदाब में अंतर उत्पन्न होते हैं। यही अंतर वायु की गति में महत्वपूर्ण भूमिका निभाते हैं।
सूर्य द्वारा पृथ्वी की सतह को असमान रूप से गर्म करने से तापमान और वायुदाब में अंतर उत्पन्न होते हैं। यही अंतर वायु की गति में महत्वपूर्ण भूमिका निभाते हैं।
3. Why is Wind Energy Renewable? | पवन ऊर्जा नवीकरणीय क्यों है?
Wind is ultimately driven by solar heating and atmospheric processes. Since these natural processes continuously replenish moving air, wind energy is considered renewable.
पवन की उत्पत्ति में सूर्य द्वारा पृथ्वी को असमान रूप से गर्म करना और वायुमंडलीय प्रक्रियाएँ महत्वपूर्ण हैं। इसलिए प्राकृतिक प्रक्रियाओं द्वारा हवा लगातार उपलब्ध होती रहती है और पवन ऊर्जा को नवीकरणीय माना जाता है।
पवन की उत्पत्ति में सूर्य द्वारा पृथ्वी को असमान रूप से गर्म करना और वायुमंडलीय प्रक्रियाएँ महत्वपूर्ण हैं। इसलिए प्राकृतिक प्रक्रियाओं द्वारा हवा लगातार उपलब्ध होती रहती है और पवन ऊर्जा को नवीकरणीय माना जाता है।
Remember: Wind energy does not require burning coal, petroleum or natural gas during electricity generation.
याद रखें: पवन टरबाइन से विद्युत उत्पादन के समय कोयला, पेट्रोलियम या प्राकृतिक गैस को जलाने की आवश्यकता नहीं होती।
याद रखें: पवन टरबाइन से विद्युत उत्पादन के समय कोयला, पेट्रोलियम या प्राकृतिक गैस को जलाने की आवश्यकता नहीं होती।
4. Animated Working Diagram | एनिमेटेड कार्य-विधि
Wind rotates the blades → rotor rotates → generator converts mechanical energy into electrical energy.
5. What is a Wind Turbine? | पवन टरबाइन क्या है?
English: A wind turbine is a machine that converts the kinetic energy of moving air into mechanical rotational energy and, through a generator, into electrical energy.
हिन्दी: पवन टरबाइन एक ऐसी मशीन है जो गतिशील वायु की गतिज ऊर्जा को पहले यांत्रिक घूर्णन ऊर्जा में और फिर जनरेटर की सहायता से विद्युत ऊर्जा में परिवर्तित करती है।
हिन्दी: पवन टरबाइन एक ऐसी मशीन है जो गतिशील वायु की गतिज ऊर्जा को पहले यांत्रिक घूर्णन ऊर्जा में और फिर जनरेटर की सहायता से विद्युत ऊर्जा में परिवर्तित करती है।
| Part | Function | हिन्दी |
|---|---|---|
| Blades | Capture energy from moving air | हवा की ऊर्जा को ग्रहण करती हैं |
| Rotor | Rotates due to wind | हवा के कारण घूमता है |
| Nacelle | Contains major mechanical/electrical components | मुख्य यांत्रिक/विद्युत भागों का आवरण |
| Gearbox | May increase rotational speed for the generator | जनरेटर के लिए घूर्णन गति बढ़ा सकता है |
| Generator | Converts mechanical energy into electrical energy | यांत्रिक ऊर्जा को विद्युत ऊर्जा में बदलता है |
| Tower | Supports turbine at height | टरबाइन को ऊँचाई पर सहारा देता है |
| Controller | Controls turbine operation | टरबाइन के संचालन को नियंत्रित करता है |
6. Working of a Wind Turbine | पवन टरबाइन की कार्य-विधि
-
Wind strikes the blades: Moving air exerts aerodynamic forces on the blades.
हवा ब्लेडों से टकराती है: गतिशील हवा ब्लेडों पर वायुगतिकीय बल लगाती है। -
Rotor rotates: The blades are attached to a hub and rotate the rotor.
रोटर घूमता है: ब्लेड हब से जुड़े होते हैं और रोटर को घुमाते हैं। -
Mechanical transmission: In many turbines, a gearbox changes rotational speed before the generator.
यांत्रिक संचरण: कई टरबाइनों में जनरेटर तक पहुँचने से पहले गियरबॉक्स घूर्णन गति बदलता है। -
Generator: The generator converts mechanical rotational energy into electrical energy.
जनरेटर: जनरेटर यांत्रिक घूर्णन ऊर्जा को विद्युत ऊर्जा में बदलता है। -
Electricity transmission: Power electronics and transformers may condition and raise the voltage for transmission to the grid.
विद्युत संचरण: विद्युत उपकरण और ट्रांसफॉर्मर आवश्यकता के अनुसार बिजली को ग्रिड तक पहुँचाने के लिए तैयार/वोल्टेज बढ़ा सकते हैं।
7. Energy Conversion in Wind Power Plant
Wind Kinetic Energy → Mechanical Energy → Electrical Energy
| Stage | Energy | Example |
|---|---|---|
| 1 | Kinetic Energy | Moving air |
| 2 | Mechanical Energy | Rotating blades and shaft |
| 3 | Electrical Energy | Generator output |
8. What is a Wind Power Plant? | पवन विद्युत संयंत्र
English: A wind power plant, or wind farm, consists of one or more wind turbines installed at a suitable site to generate electricity from wind.
हिन्दी: पवन विद्युत संयंत्र या Wind Farm एक ऐसा क्षेत्र है जहाँ एक या अनेक पवन टरबाइन स्थापित करके हवा की ऊर्जा से विद्युत उत्पन्न की जाती है।
हिन्दी: पवन विद्युत संयंत्र या Wind Farm एक ऐसा क्षेत्र है जहाँ एक या अनेक पवन टरबाइन स्थापित करके हवा की ऊर्जा से विद्युत उत्पन्न की जाती है।
Wind Farm: A group of wind turbines operating in the same geographical area is commonly called a wind farm.
Wind Farm: एक ही क्षेत्र में स्थापित कई पवन टरबाइनों के समूह को सामान्यतः Wind Farm कहा जाता है।
Wind Farm: एक ही क्षेत्र में स्थापित कई पवन टरबाइनों के समूह को सामान्यतः Wind Farm कहा जाता है।
9. Wind Farm Layout | पवन ऊर्जा फार्म
10. Factors Affecting Wind Power Generation
| Factor | Effect |
|---|---|
| Wind Speed | Strongly affects available wind power. |
| Rotor Size | Larger swept area can capture more wind energy. |
| Air Density | Higher air density generally means more available wind power at the same speed. |
| Site Location | Open and windy locations are generally more suitable. |
| Wind Direction | Turbine orientation/yaw system helps face the wind. |
| Terrain | Mountains, buildings and rough terrain can influence wind flow. |
Available wind power ∝ ρ A v³
Where:
ρ = air density
A = swept area of rotor
v = wind speed
Therefore, wind speed has a very strong effect because it appears as the cube of speed.
ρ = air density
A = swept area of rotor
v = wind speed
Therefore, wind speed has a very strong effect because it appears as the cube of speed.
11. Important Numerical Concept | महत्वपूर्ण संख्यात्मक अवधारणा
Question: If wind speed increases from 5 m/s to 10 m/s, how does the available wind power change, assuming other factors remain constant?
Since P ∝ v³:
P₂/P₁ = (10/5)³ = 2³ = 8
Therefore, the available wind power becomes approximately 8 times.
अर्थात पवन की गति दोगुनी होने पर उपलब्ध पवन शक्ति लगभग 8 गुना हो सकती है।
P₂/P₁ = (10/5)³ = 2³ = 8
Therefore, the available wind power becomes approximately 8 times.
अर्थात पवन की गति दोगुनी होने पर उपलब्ध पवन शक्ति लगभग 8 गुना हो सकती है।
12. Suitable Locations for Wind Power Plants
Wind power plants are generally installed in areas having adequate and relatively consistent wind resources, such as coastal regions, open plains, mountain passes and other suitable elevated/open locations.
पवन विद्युत संयंत्र सामान्यतः ऐसे क्षेत्रों में लगाए जाते हैं जहाँ पर्याप्त और अपेक्षाकृत स्थिर पवन उपलब्ध हो, जैसे तटीय क्षेत्र, खुले मैदान, पर्वतीय दर्रे तथा उपयुक्त ऊँचे/खुले स्थान।
पवन विद्युत संयंत्र सामान्यतः ऐसे क्षेत्रों में लगाए जाते हैं जहाँ पर्याप्त और अपेक्षाकृत स्थिर पवन उपलब्ध हो, जैसे तटीय क्षेत्र, खुले मैदान, पर्वतीय दर्रे तथा उपयुक्त ऊँचे/खुले स्थान।
Important: A windy-looking location is not enough. Actual wind-resource assessment and technical, environmental and grid studies are required before developing a wind farm.
13. Advantages of Wind Energy | पवन ऊर्जा के लाभ
- Renewable source of energy.
- Fuel is not consumed during normal electricity generation.
- Very low operational greenhouse-gas emissions compared with fossil-fuel electricity generation.
- Reduces dependence on coal and other fossil fuels.
- Water consumption during normal wind generation is generally low.
- Wind turbines can be installed in groups as wind farms.
- Land around turbines may sometimes continue to be used for farming or grazing, depending on local conditions.
- Suitable for both large-scale and certain distributed applications.
14. Limitations of Wind Energy | पवन ऊर्जा की सीमाएँ
- Wind is variable and not available at a constant speed.
- Electricity generation depends strongly on wind conditions.
- Suitable sites may be limited.
- Large wind farms require substantial land area and infrastructure.
- Turbines can produce aerodynamic and mechanical noise.
- Visual impact may be significant for some communities.
- Bird and bat interactions require appropriate assessment and mitigation.
- Transmission infrastructure may be required when windy sites are far from demand centres.
- Initial installation cost can be significant.
15. Wind Energy vs Solar Energy
| Feature | Wind Energy | Solar Energy |
|---|---|---|
| Source | Moving air | Sunlight |
| Main Device | Wind turbine | Solar cell / solar thermal system |
| Energy Conversion | Kinetic → Mechanical → Electrical | Radiant → Electrical / Thermal |
| Night Operation | Possible if sufficient wind is available | Solar PV does not generate sunlight-based electricity at night without storage/backup |
| Major Limitation | Variable wind | Variable sunlight |
16. Wind Energy vs Fossil Fuels
| Wind Energy | Fossil Fuels |
|---|---|
| Renewable | Non-renewable |
| No fuel combustion during normal generation | Fuel is burned to release energy |
| Very low operational emissions | Produces CO₂ and other pollutants during combustion |
| Depends on wind availability | Can generally be dispatched when fuel is available and plant is operational |
17. Wind Energy in India | भारत में पवन ऊर्जा
India has significant wind-energy potential, particularly in several coastal and interior regions. Wind projects are developed where wind resources, land availability, grid connectivity and other technical/environmental factors are suitable.
भारत में पवन ऊर्जा की अच्छी संभावनाएँ हैं, विशेषकर कई तटीय तथा आंतरिक क्षेत्रों में। पवन परियोजनाएँ वहाँ विकसित की जाती हैं जहाँ पवन संसाधन, भूमि, ग्रिड कनेक्टिविटी और अन्य तकनीकी/पर्यावरणीय परिस्थितियाँ अनुकूल हों।
भारत में पवन ऊर्जा की अच्छी संभावनाएँ हैं, विशेषकर कई तटीय तथा आंतरिक क्षेत्रों में। पवन परियोजनाएँ वहाँ विकसित की जाती हैं जहाँ पवन संसाधन, भूमि, ग्रिड कनेक्टिविटी और अन्य तकनीकी/पर्यावरणीय परिस्थितियाँ अनुकूल हों।
For current state-wise installed-capacity figures or rankings, always use the latest official government data because capacities change over time.
18. Onshore and Offshore Wind Energy
| Onshore Wind | Offshore Wind |
|---|---|
| Turbines installed on land | Turbines installed in sea/ocean areas |
| Generally easier access and maintenance | Can access strong marine wind resources |
| Land and local terrain matter | Marine construction and underwater/grid infrastructure are important |
19. Capacity Factor | क्षमता कारक
Capacity factor compares the actual energy generated by a power plant over a period with the energy it would have generated if it had operated at its rated maximum power continuously during that entire period.
Capacity Factor =
Actual Energy Generated ÷ (Rated Power × Time)
A wind turbine does not normally produce its rated maximum power all the time because wind speed continuously changes.
20. Does Wind Energy Need a Battery?
No, not necessarily. Utility-scale wind farms can feed electricity into the grid without storing all generated electricity in batteries. However, batteries or other storage technologies can be used to help manage variability and match generation with demand.
हिन्दी: पवन ऊर्जा के लिए बैटरी अनिवार्य नहीं है। बड़े Wind Farms सीधे Grid को बिजली दे सकते हैं। लेकिन Battery Storage या अन्य Energy Storage तकनीकें उत्पादन की अनियमितता को प्रबंधित करने और मांग के साथ आपूर्ति को बेहतर ढंग से मिलाने में मदद कर सकती हैं।
हिन्दी: पवन ऊर्जा के लिए बैटरी अनिवार्य नहीं है। बड़े Wind Farms सीधे Grid को बिजली दे सकते हैं। लेकिन Battery Storage या अन्य Energy Storage तकनीकें उत्पादन की अनियमितता को प्रबंधित करने और मांग के साथ आपूर्ति को बेहतर ढंग से मिलाने में मदद कर सकती हैं।
21. Important Terms | महत्वपूर्ण शब्द
| Term | Meaning |
|---|---|
| Wind Energy | Energy associated with moving air. |
| Wind Turbine | Machine that extracts energy from wind and drives a generator. |
| Rotor | Rotating assembly of blades and hub. |
| Nacelle | Housing containing major turbine components. |
| Wind Farm | Group of wind turbines at one site/area. |
| Onshore | Located on land. |
| Offshore | Located in marine waters. |
| Capacity Factor | Ratio comparing actual energy generation with maximum possible generation over the period. |
| Renewable Energy | Energy obtained from naturally replenished sources. |
22. 30 MCQs | बहुविकल्पीय प्रश्न
1. Wind energy is primarily associated with the:
A. Kinetic energy of moving air
B. Chemical energy of coal
C. Nuclear energy of atoms
D. Chemical energy of petrol
Answer: A — Moving air possesses kinetic energy.
2. A wind turbine converts wind energy first into:
A. Chemical energy
B. Mechanical rotational energy
C. Nuclear energy
D. Sound energy
Answer: B
3. The final useful output of a wind power plant is generally:
A. Heat
B. Light
C. Electrical energy
D. Chemical energy
Answer: C
4. A group of wind turbines installed in the same area is called a:
A. Solar park
B. Thermal station
C. Hydroelectric plant
D. Wind farm
Answer: D
5. Wind energy is classified as:
A. Renewable energy
B. Non-renewable energy
C. Fossil-fuel energy
D. Nuclear fuel energy
Answer: A
6. Which component rotates due to wind?
A. Transformer
B. Rotor
C. Fuse
D. Battery
Answer: B
7. The generator in a wind turbine converts:
A. Electrical energy into chemical energy
B. Heat into sound
C. Mechanical energy into electrical energy
D. Electrical energy into nuclear energy
Answer: C
8. Which factor has a particularly strong effect on available wind power?
A. Colour of turbine
B. Tower paint
C. Cable length only
D. Wind speed
Answer: D
9. Approximately how does available wind power vary with wind speed?
A. v³
B. v
C. 1/v
D. v² only
Answer: A
10. Which part generally contains major turbine machinery?
A. Foundation only
B. Nacelle
C. Road
D. Transformer oil tank only
Answer: B
11. Which is a renewable source?
A. Coal
B. Petroleum
C. Wind
D. Natural gas
Answer: C
12. Offshore wind turbines are installed:
A. Inside coal mines
B. Inside deserts only
C. On railway tracks
D. In marine areas
Answer: D
13. Which energy drives the rotor of a wind turbine?
A. Kinetic energy of wind
B. Chemical energy of petrol
C. Nuclear energy
D. Electrical energy from grid
Answer: A
14. A gearbox in many wind turbines is used mainly to:
A. Store electricity
B. Change rotational speed
C. Produce coal
D. Absorb sunlight
Answer: B
15. Which is NOT a direct advantage of wind energy?
A. Renewable resource
B. No fuel combustion during normal operation
C. Constant wind at every location
D. Low operational emissions
Answer: C
16. A wind farm requires:
A. Only one blade
B. No wind
C. A coal mine
D. Suitable wind resources
Answer: D
17. If wind speed doubles, available wind power approximately becomes:
A. 8 times
B. 2 times
C. 4 times
D. Half
Answer: A
18. Which parameter represents rotor swept area?
A. A
B. V
C. I
D. R
Answer: A
19. Wind power generation is generally:
A. Completely independent of weather
B. Variable
C. Based on coal combustion
D. Based on uranium fission
Answer: B
20. The tower of a wind turbine mainly:
A. Stores fuel
B. Produces sunlight
C. Supports the turbine at height
D. Produces coal
Answer: C
21. Which source ultimately drives most atmospheric wind patterns?
A. Moonlight only
B. Coal
C. Petroleum
D. Solar heating of Earth
Answer: D
22. Which of the following can influence wind turbine output?
A. Wind speed
B. Wind direction
C. Air density
D. All of these
Answer: D
23. A wind turbine generator primarily produces:
A. Electrical energy
B. Chemical energy
C. Nuclear energy
D. Potential energy only
Answer: A
24. Onshore wind means turbines located:
A. In deep oceans
B. On land
C. Inside lakes
D. In underground mines
Answer: B
25. Which is a limitation of wind energy?
A. Wind is always constant
B. It requires no site selection
C. Wind availability is variable
D. It always produces electricity at rated power
Answer: C
26. Capacity factor compares actual generation with:
A. Coal consumption
B. Fuel cost
C. Battery voltage
D. Maximum possible generation at rated power over the period
Answer: D
27. Which component may be used to increase shaft speed before a generator?
A. Gearbox
B. Fuse
C. Solar cell
D. Ammeter
Answer: A
28. Wind power is classified as:
A. Fossil fuel energy
B. Renewable energy
C. Nuclear energy
D. Chemical fuel energy
Answer: B
29. Which statement is correct?
A. Wind turbines need coal to rotate
B. Wind farms cannot supply electricity to a grid
C. Wind energy can be integrated into an electricity grid
D. Wind energy is non-renewable
Answer: C
30. The correct energy sequence is:
A. Electrical → Wind → Chemical
B. Chemical → Wind → Nuclear
C. Heat → Chemical → Wind
D. Wind → Mechanical → Electrical
Answer: D
23. 30 Subjective Questions with Answers
2 Marks
Q1. What is wind energy?
Wind energy is the energy associated with moving air. It is mainly the kinetic energy of wind that can be converted into useful mechanical or electrical energy.
पवन ऊर्जा गतिशील वायु से संबंधित ऊर्जा है, जिसे यांत्रिक या विद्युत ऊर्जा में बदला जा सकता है।
पवन ऊर्जा गतिशील वायु से संबंधित ऊर्जा है, जिसे यांत्रिक या विद्युत ऊर्जा में बदला जा सकता है।
2 Marks
Q2. Why is wind energy renewable?
Because wind is continuously replenished by natural atmospheric processes, largely driven by solar heating of Earth's surface.
2 Marks
Q3. What is a wind turbine?
A wind turbine is a machine that extracts energy from moving air and uses the resulting rotation to drive a generator.
2 Marks
Q4. What is a wind farm?
A wind farm is a group of wind turbines installed in a suitable geographical area for generating electricity.
2 Marks
Q5. What is the role of the generator in a wind turbine?
The generator converts the mechanical rotational energy of the turbine shaft into electrical energy.
3 Marks
Q6. Explain the energy conversion in a wind power plant.
The kinetic energy of moving air rotates the turbine blades. The rotor and shaft provide mechanical rotational energy. The generator then converts this mechanical energy into electrical energy.
3 Marks
Q7. Mention three factors affecting wind power generation.
Wind speed, rotor swept area and air density are three important factors. Site conditions and turbine efficiency also affect actual generation.
3 Marks
Q8. Why are wind turbines installed at considerable height?
Wind conditions can be stronger and less affected by surface obstacles at greater heights. A suitable height can therefore improve access to useful wind resources.
3 Marks
Q9. Write three advantages of wind energy.
1. It is renewable.
2. No fuel is burned during normal electricity generation.
3. Operational greenhouse-gas emissions are very low compared with fossil-fuel generation.
2. No fuel is burned during normal electricity generation.
3. Operational greenhouse-gas emissions are very low compared with fossil-fuel generation.
3 Marks
Q10. Write three limitations of wind energy.
Wind is variable, suitable sites are limited, and wind farms can have environmental, visual, noise and transmission-related considerations.
3 Marks
Q11. Differentiate between onshore and offshore wind energy.
Onshore turbines are installed on land, whereas offshore turbines are installed in marine areas. Offshore projects can access marine wind resources but require specialized marine construction and infrastructure.
3 Marks
Q12. Why is wind speed important for wind power?
Available wind power is approximately proportional to the cube of wind speed. Therefore, even a moderate increase in wind speed can produce a large increase in available power.
4 Marks
Q13. Explain the construction of a typical wind turbine.
A typical turbine includes blades, hub and rotor, nacelle, shaft, generator, tower and control systems. Many designs also use a gearbox. The tower supports the nacelle and rotor at an appropriate height.
4 Marks
Q14. Explain the working of a wind turbine step by step.
Wind applies aerodynamic force to the blades. The blades rotate the hub and rotor. The shaft transfers mechanical rotation to the generator, directly or through a gearbox. The generator converts mechanical energy into electrical energy.
4 Marks
Q15. Explain why wind farms need proper site selection.
A suitable site must have adequate wind resources, appropriate terrain, land availability, access for construction and maintenance, grid connectivity and acceptable environmental conditions. Wind-resource assessment is therefore essential.
4 Marks
Q16. Explain the importance of rotor swept area.
The rotor sweeps an area through which wind passes. Larger swept area allows a turbine to intercept more moving air under comparable wind conditions. Thus, available wind power increases with rotor swept area.
4 Marks
Q17. What is capacity factor?
Capacity factor is the ratio of actual energy generated over a period to the energy that would have been generated if the plant operated continuously at rated power during that period.
4 Marks
Q18. Explain two environmental considerations associated with wind farms.
Possible considerations include noise and visual impact, as well as interactions with birds and bats. Proper site assessment, turbine design and mitigation measures can reduce these impacts.
5 Marks
Q19. Explain wind power generation with a labelled diagram.
The wind rotates turbine blades. The rotor transfers mechanical rotation to a shaft. A gearbox may alter the speed. The generator converts mechanical energy into electrical energy. Power electronics and a transformer may then condition and raise the voltage before grid transmission.
5 Marks
Q20. Discuss the advantages and limitations of wind energy.
Advantages: renewable, no fuel combustion during operation, low operational emissions, low water use during normal generation and modular installation.
Limitations: variable output, site dependence, land/infrastructure requirements, noise/visual considerations, wildlife considerations and possible transmission needs.
Limitations: variable output, site dependence, land/infrastructure requirements, noise/visual considerations, wildlife considerations and possible transmission needs.
5 Marks
Q21. Explain why wind energy cannot always supply constant power.
Wind speed changes with time and location. Since available power depends strongly on wind speed, turbine output also varies. Grid systems therefore balance wind generation with other generators, demand response, transmission and/or storage.
5 Marks
Q22. Compare wind energy and solar energy.
Wind energy uses moving air and turbines, whereas solar photovoltaic energy uses sunlight and solar cells. Both are renewable but variable. Wind can generate electricity at night if wind is available, while solar PV requires sunlight and therefore normally needs storage or other sources for night-time supply.
5 Marks
Q23. Explain the role of the gearbox in a wind turbine.
The rotor often turns at a relatively low rotational speed. In geared turbines, a gearbox can increase the rotational speed suitable for the generator. Some modern turbines use direct-drive generators and therefore do not require a conventional gearbox.
6 Marks
Q24. Describe a complete wind power plant from wind to grid.
Wind strikes the blades and rotates the rotor. The shaft transfers mechanical energy, with a gearbox used in many designs. The generator converts mechanical energy into electricity. Power-electronic equipment may control and condition the output. A transformer can raise voltage for efficient transmission. The electricity is then supplied to the grid.
6 Marks
Q25. Derive the dependence of available wind power on wind speed.
The kinetic energy of a mass m moving with speed v is:
E = ½mv²
Mass flow rate of air through area A is proportional to ρAv. Therefore power, which is energy per unit time, becomes proportional to:
P ∝ ρAv³
Thus wind power depends on the cube of wind speed.
E = ½mv²
Mass flow rate of air through area A is proportional to ρAv. Therefore power, which is energy per unit time, becomes proportional to:
P ∝ ρAv³
Thus wind power depends on the cube of wind speed.
6 Marks
Q26. A turbine experiences a doubling of wind speed. Explain its effect on available wind power.
Since P ∝ v³:
P₂/P₁ = (2v)³/v³ = 8.
Therefore the theoretical available wind power becomes eight times, assuming air density, swept area and other conditions remain constant.
P₂/P₁ = (2v)³/v³ = 8.
Therefore the theoretical available wind power becomes eight times, assuming air density, swept area and other conditions remain constant.
6 Marks
Q27. Explain why wind energy is considered cleaner than fossil-fuel electricity generation during operation.
Wind turbines do not burn coal, oil or gas to generate electricity during normal operation. Therefore they do not produce combustion-related CO₂ and air pollutants at the point of electricity generation in the same way fossil-fuel plants do. However, wind turbines still have lifecycle environmental impacts from manufacturing, transport, construction and disposal.
6 Marks
Q28. Explain onshore and offshore wind power in detail.
Onshore wind turbines are installed on land and generally have easier access for construction and maintenance. Offshore turbines are installed in marine environments and can access strong wind resources but require specialized foundations, marine installation, subsea/grid infrastructure and maintenance systems.
6 Marks
Q29. Explain the importance of wind-resource assessment before building a wind farm.
Wind-resource assessment determines wind speed, direction, variability and other characteristics at a proposed site. Long-term measurements and modelling help estimate energy production, turbine suitability, economic feasibility and grid requirements. It also supports environmental and engineering planning.
6 Marks
Q30. Explain the complete concept of wind energy in an exam-ready answer.
Wind energy is the kinetic energy of moving air. A wind turbine captures part of this energy through aerodynamic forces on its blades. The rotor and shaft convert it into mechanical rotation. A generator converts the mechanical energy into electrical energy. Multiple turbines form a wind farm. Wind energy is renewable and has low operational emissions, but its output varies with wind conditions and suitable sites, infrastructure and environmental considerations are important.
24. Assertion–Reason Questions
Q1. Assertion: Wind energy is a renewable source.
Reason: Natural atmospheric processes continuously replenish moving air.
Reason: Natural atmospheric processes continuously replenish moving air.
Answer: Both Assertion and Reason are true, and the Reason correctly explains the Assertion.
Q2. Assertion: Wind power strongly depends on wind speed.
Reason: Available wind power is approximately proportional to the cube of wind speed.
Reason: Available wind power is approximately proportional to the cube of wind speed.
Answer: Both are true, and the Reason correctly explains the Assertion.
Q3. Assertion: A wind turbine directly converts all wind energy into electricity.
Reason: The turbine blades rotate a generator without any intermediate mechanical process.
Reason: The turbine blades rotate a generator without any intermediate mechanical process.
Answer: Assertion is false and Reason is false. Wind energy is first converted into mechanical rotational energy, which drives the generator.
Q4. Assertion: Wind farms require suitable site selection.
Reason: Wind speed and wind characteristics vary from place to place.
Reason: Wind speed and wind characteristics vary from place to place.
Answer: Both are true, and the Reason correctly explains the Assertion.
Q5. Assertion: Wind power output is always constant.
Reason: Wind speed remains exactly constant throughout the day.
Reason: Wind speed remains exactly constant throughout the day.
Answer: Both Assertion and Reason are false.
25. HOTS / Competency-Based Questions
HOTS 1: Two locations have the same rotor size, but Location A has an average wind speed twice that of Location B. Which location has much greater theoretical wind-power availability?
Location A. Since P ∝ v³, doubling wind speed gives approximately 8 times the available wind power, all else equal.
HOTS 2: Why would a wind farm be unsuitable at a location where wind speed is generally very low?
Because the available wind power falls very rapidly with decreasing wind speed. Since P ∝ v³, low wind speed can result in insufficient energy production.
HOTS 3: Why are wind turbines generally installed in open areas rather than immediately behind tall buildings?
Buildings can obstruct and disturb airflow, producing turbulence and reducing the quality of the wind resource. Open sites can provide more suitable and predictable wind conditions.
HOTS 4: Can wind energy be called completely pollution-free?
It is better to say that wind electricity has very low operational emissions and no fuel combustion during normal operation. Manufacturing, transportation, construction and end-of-life processes still have environmental impacts.
HOTS 5: Why can a wind turbine sometimes produce less electricity even though it is rotating?
Rotation alone does not mean rated power output. Electrical output depends on wind speed, turbine operating conditions, generator characteristics and control systems. The turbine may rotate at low power when wind conditions are not strong enough for rated output.
26. Golden Points for Exam | परीक्षा के लिए महत्वपूर्ण बिंदु
- Wind energy = kinetic energy of moving air.
- Wind energy is renewable.
- Wind turbine converts wind energy into mechanical rotation and then electrical energy.
- Rotor consists of blades and hub.
- Nacelle contains major turbine machinery.
- Generator converts mechanical energy into electrical energy.
- Several turbines together form a wind farm.
- Available wind power is approximately proportional to ρAv³.
- Wind speed has a cubic effect on available power.
- Wind output is variable.
- Onshore = land-based; Offshore = marine-based.
- Wind-resource assessment is essential before selecting a site.
- Wind power has low operational greenhouse-gas emissions compared with fossil-fuel generation.
- Wind farms require consideration of grid connection, land, environment and local conditions.
27. One-Minute Revision | एक मिनट में Revision
🌬️ Wind → 🌀 Rotor → ⚙️ Shaft/Gearbox → ⚡ Generator → 🔌 Grid
Wind: Moving air
Energy: Kinetic
Device: Wind turbine
Output: Electricity
Group: Wind farm
Key factor: Wind speed
Power relation: P ∝ ρAv³
Onshore: Land
Offshore: Sea/marine area
Main limitation: Variable wind
Energy: Kinetic
Device: Wind turbine
Output: Electricity
Group: Wind farm
Key factor: Wind speed
Power relation: P ∝ ρAv³
Onshore: Land
Offshore: Sea/marine area
Main limitation: Variable wind
28. Concept Map | अवधारणा मानचित्र
29. Final Summary | अंतिम सारांश
Wind energy is a renewable form of energy obtained from moving air. Wind turbines capture a portion of the kinetic energy of wind and convert it into mechanical rotational energy. A generator then converts this mechanical energy into electricity. A group of turbines forms a wind farm or wind power plant.
The amount of available wind power depends strongly on wind speed and is approximately proportional to the cube of wind speed. Therefore, selecting a location with a good wind resource is extremely important.
पवन ऊर्जा गतिशील वायु से प्राप्त नवीकरणीय ऊर्जा है। पवन टरबाइन हवा की गतिज ऊर्जा को यांत्रिक घूर्णन ऊर्जा में तथा जनरेटर की सहायता से विद्युत ऊर्जा में बदलती है। कई टरबाइनों का समूह Wind Farm कहलाता है।
पवन ऊर्जा के प्रमुख लाभ हैं—नवीकरणीय होना, सामान्य संचालन में ईंधन न जलाना और कम परिचालन उत्सर्जन। इसकी प्रमुख सीमाएँ हैं—हवा की परिवर्तनशीलता, उपयुक्त स्थान की आवश्यकता तथा पर्यावरणीय, भूमि और ग्रिड संबंधी विचार।
The amount of available wind power depends strongly on wind speed and is approximately proportional to the cube of wind speed. Therefore, selecting a location with a good wind resource is extremely important.
पवन ऊर्जा गतिशील वायु से प्राप्त नवीकरणीय ऊर्जा है। पवन टरबाइन हवा की गतिज ऊर्जा को यांत्रिक घूर्णन ऊर्जा में तथा जनरेटर की सहायता से विद्युत ऊर्जा में बदलती है। कई टरबाइनों का समूह Wind Farm कहलाता है।
पवन ऊर्जा के प्रमुख लाभ हैं—नवीकरणीय होना, सामान्य संचालन में ईंधन न जलाना और कम परिचालन उत्सर्जन। इसकी प्रमुख सीमाएँ हैं—हवा की परिवर्तनशीलता, उपयुक्त स्थान की आवश्यकता तथा पर्यावरणीय, भूमि और ग्रिड संबंधी विचार।
📘 Class 10 CBSE Science
Sources of Energy | Wind Energy and Wind Power Plants
NCERT + Foundation + Competitive Preparation
Sources of Energy | Wind Energy and Wind Power Plants
NCERT + Foundation + Competitive Preparation
