Energy and Environment MCQ Quiz - Objective Question with Answer for Energy and Environment - Download Free PDF

Explanation:

Semiconductors Used in Crystalline Solar PV Modules

In the manufacturing of crystalline solar photovoltaic (PV) modules, the choice of semiconductor material is crucial for the efficiency and performance of the solar cells. Various semiconductor materials can be used, each with its own advantages and applications. The common options include:

• Gallium arsenide (GaAs): Known for its high efficiency, but it is expensive and not commonly used in large-scale PV module production.

• Cadmium telluride (CdTe): Used in thin-film solar cells and has good efficiency, but it is not typically used in crystalline PV modules.

• Amorphous silicon (a-Si): Another type of thin-film technology, less efficient compared to crystalline silicon, and not commonly used in crystalline PV modules.

• Monocrystalline silicon (mono-Si): The most commonly used semiconductor in crystalline solar PV modules due to its high efficiency and reliability.

Analyzing the Given Options

1. "Gallium arsenide" (Option 1)

   • Although GaAs cells have high efficiency, their high cost makes them less favorable for large-scale production.

   • Thus, it is not the most commonly used semiconductor in crystalline PV modules.

2. "Cadmium telluride" (Option 2)

   • CdTe is primarily used in thin-film solar cells, not crystalline PV modules.

   • Therefore, it is not the correct answer for crystalline PV modules.

3. "Amorphous silicon" (Option 3)

   • Amorphous silicon is another thin-film technology, which is less efficient and less commonly used in crystalline PV modules.

   • Thus, it is not the most commonly used semiconductor in crystalline PV modules.

4. "Monocrystalline silicon" (Option 4)

   • Monocrystalline silicon is highly efficient and widely used in crystalline PV modules.

   • Therefore, it is the correct and most commonly used semiconductor in crystalline solar PV modules.

Explanation:

Reducing Levelized Cost of Electricity (LCOE) in Renewable Energy Plants

Levelized Cost of Electricity (LCOE) is a measure of the average net present cost of electricity generation for a generator over its lifetime. It is influenced by various factors, and reducing the LCOE is critical for making renewable energy plants more economically viable. The following analysis explains how different parameters affect the LCOE:

1. "Higher discount rate" (Increases LCOE)

   • A higher discount rate increases the present value of future costs, leading to a higher LCOE.

   • This makes the investment less attractive as the future savings are worth less today.

2. "Shorter plant lifetime" (Increases LCOE)

   • A shorter plant lifetime means that the capital costs have to be recovered over a shorter period, increasing the LCOE.

   • This leads to higher annual costs and reduces the economic efficiency of the plant.

3. "Lower O&M costs" (Reduces LCOE)

   • Lower operation and maintenance (O&M) costs reduce the annual costs associated with running the plant.

   • This directly reduces the LCOE, making the electricity generation more economical.

4. "Higher land cost" (Increases LCOE)

   • Higher land costs increase the initial capital expenditure required to establish the plant.

   • This higher upfront cost leads to a higher LCOE as these costs are spread over the electricity generated during the plant's lifetime.

Explanation:

Maturity of Renewable Energy Technologies in India

In the context of renewable energy implementation in India, different technologies are at different levels of maturity. The maturity of these technologies can be analyzed based on their current adoption, government policies, and technological advancements.

• Solar PV (Photovoltaic): Solar PV technology has witnessed significant growth in India due to government initiatives like the National Solar Mission. It is widely adopted, and the country has become one of the largest markets for solar energy in the world.

• Onshore Wind: Onshore wind energy is another mature technology in India. With substantial installed capacity and favorable wind conditions in various regions, wind energy contributes significantly to the renewable energy mix.

• Biomass Gasification: Biomass gasification has been explored for rural electrification and small-scale power generation. While it has potential, its adoption is not as widespread as solar PV and wind energy.

• Tidal Energy: Tidal energy is still in its nascent stage in India. There have been pilot projects, but large-scale implementation is limited due to technological and economic challenges.

Analyzing the Given Options

1. Option 1: "A > D > B > C"

   • This option places Solar PV as the most mature, followed by Onshore Wind, Biomass Gasification, and Tidal Energy.

   • This correctly reflects the current state of renewable energy technologies in India, with Solar PV and Onshore Wind being the most mature and widely implemented.

2. Option 2: "A > C > D > B"

   • This option places Tidal Energy above Onshore Wind and Biomass Gasification, which is not accurate as Tidal Energy is less mature and less implemented in India.

   • Therefore, this option does not correctly reflect the maturity levels.

3. Option 3: "D > A > B > C"

   • This option places Onshore Wind above Solar PV, which is debatable as both have significant adoption, but Solar PV has seen more recent growth and investment.

   • Given the recent trends, Solar PV could be considered slightly more mature than Onshore Wind in India.

4. Option 4: "B > A > D > C"

   • This option places Biomass Gasification above Solar PV and Onshore Wind, which is not accurate as Biomass Gasification is less mature and less widely implemented.

   • Therefore, this option does not correctly reflect the maturity levels.

Explanation:

Green Energy Systems Requiring Consistent Base-Load Heat Source

Certain green energy systems require a consistent and reliable heat source, such as geothermal gradient or deep aquifer, to generate energy. These systems utilize the Earth's natural heat to produce power and need a steady base-load heat source to function effectively. The options provided are:

• Wave energy – This system harnesses energy from the surface motion of ocean waves. It does not rely on a heat source.

• Tidal barrage – This system generates energy by trapping and releasing water through turbines during tidal cycles. It is not dependent on a heat source.

• Enhanced Geothermal Systems (EGS) – This system relies on extracting heat from deep within the Earth, using geothermal gradients or deep aquifers. It requires a consistent base-load heat source.

• Passive solar architecture – This design approach utilizes the sun's energy for heating and cooling buildings without mechanical systems. It does not need a consistent base-load heat source.

Analyzing the Given Options

1. "Wave energy" (Option 1)

   • Wave energy captures the kinetic energy from ocean waves. It does not require a geothermal gradient or deep aquifer heat source.

2. "Tidal barrage" (Option 2)

   • Tidal barrage systems utilize the potential energy from tidal movements. They do not depend on a geothermal heat source.

3. "Enhanced Geothermal Systems (EGS)" (Option 3)

   • EGS systems extract heat from deep within the Earth, necessitating a consistent base-load heat source such as a geothermal gradient or deep aquifer.

4. "Passive solar architecture" (Option 4)

   • Passive solar architecture uses the design of buildings to utilize sunlight for heating and cooling. It does not require a consistent base-load heat source.

Conclusion

After analyzing all the options, it is clear that Enhanced Geothermal Systems (EGS) (Option 3) is the green energy system that requires a consistent base-load heat source like a geothermal gradient or deep aquifer.

Explanation:

Maximum Power Point Tracking (MPPT) in Grid-Connected Solar Plants

In grid-connected solar plants, MPPT (Maximum Power Point Tracking) is a technique used to maximize the power extraction from the solar panels. This is achieved by continuously adjusting the electrical operating point of the modules or array. The primary goal is to ensure that the solar panels operate at their maximum power point (MPP), which is the point at which the product of current (I) and voltage (V) is maximized. Let's analyze the given options to understand why option 3 is the correct answer:

1. Protect modules from overvoltage (Incorrect)

   • While protecting modules from overvoltage is important, it is not the primary function of MPPT. Overvoltage protection is typically handled by other components in the system.

2. Stabilize grid frequency (Incorrect)

   • Grid frequency stabilization is managed by grid operators and power electronics, not by the MPPT. MPPT focuses on maximizing power output from the solar panels.

3. Maximize power extraction by matching load and I-V curve (Correct)

   • This is the correct answer because MPPT is specifically designed to track the maximum power point on the I-V curve of the solar panels. By continuously adjusting the load, the MPPT ensures that the panels operate at their optimal power output, thereby maximizing the energy harvested.

4. Avoid shading losses (Incorrect)

   • Shading losses are minimized by proper design and layout of the solar array rather than MPPT. While MPPT can help optimize performance under partial shading, its primary function is to maximize power output, not specifically to avoid shading losses.

The correct answer is tidal.Key Points

• Tidal energy is the correct answer for utilising in the Gulf of Khambhat, the Gulf of Kutch and Sundarbans region in India.
• Tidal energy is generated by the gravitational forces of the moon and the sun on the earth's water bodies.
• The Gulf of Khambhat and the Gulf of Kutch are known for their strong tidal currents, making them ideal locations for tidal energy projects.
• The Sundarbans region, located in the delta of the Ganges, Brahmaputra and Meghna rivers, has a vast network of tidal creeks and channels which can be used to generate tidal energy.

Additional Information

• The most advanced and developed renewable energy source is wind energy.
  • By harnessing the kinetic energy created by air currents, it uses wind to create electricity. 
• The energy present in a system that determines its temperature is referred to as thermal energy.
  • Thermal energy flows as heat.
• Any energy produced by the sun is referred to as solar energy.
  • Nuclear fusion occurs in the sun and produces solar energy.

The correct answer is Sun.Key Points

• The ultimate source of energy for all living organisms is the sun.
• The sun provides energy to plants through the process of photosynthesis.
• Animals then consume plants (or other animals that have consumed plants) to obtain energy.
• This energy is then used for various processes such as growth, reproduction, and movement.
• Without the sun, life on Earth would not be possible.​

Additional Information

• Soil: While soil does provide nutrients and water to plants, it is not the ultimate source of energy for living organisms.
• Water: Water is essential for life, but it is not a direct source of energy.
• Air: While oxygen is required for respiration, it is not the ultimate source of energy.

The correct answer is Methane.

Key Points

• Biogas is primarily composed of methane gas, which is the major component of biogas.
• Methane gas makes up about 50-75% of biogas, while the remaining 25-50% is made up of carbon dioxide, water vapor, and trace amounts of other gases.
• Biogas is a gaseous renewable energy source.
• Anaerobic digestion using methanogens or anaerobic organisms in a bioreactor, biodigester, or anaerobic digester produces biogas.
• The main components of the gas are methane (CH₄) and carbon dioxide (CO₂), with trace amounts of moisture, siloxanes, and hydrogen sulfide (H₂S).

Additional Information

• Compressed natural gas:
  • CNG is a fossil fuel that is primarily composed of methane gas.
  • CNG is commonly used as a fuel for vehicles and is produced from natural gas reserves.
• Hydrogen gas:
  • It is a colorless, odorless, tasteless, and highly flammable gas.
  • It is commonly used in fuel cells to generate electricity.
• Liquefied petroleum gas:
  • It is a mixture of propane and butane gases.
  • It is commonly used as a fuel for heating and cooking.

The correct answer is Karanja (Pongamia pinnata).

 Key Points

• Karanja (Pongamia pinnata) trees are normally planted along highways, roads, and canals to stop soil erosion. 
• It is found as one of the most suitable non-edible oil plant species in India due to its good N₂ fixing ability and not being grazable and eatable by animals.
• It can be grown in water-logged, saline and alkaline soil, wasteland/ fallow land and can withstand harsh agro-climates.
• The seeds of Pongamia pinnata contain 30 to 40% oil which is thick, reddish brown in colour oil known as Pongam/Pongamol/Hongay oil which can be converted to biodiesel by transesterification with methanol in the presence of KOH.
• Areas with good natural populations of Pongamia provide a great opportunity for the production of bio-diesel on a local scale and will be able to source germplasm for the development of the resource.

Therefore, the correct answer is Karanja (Pongamia pinnata).

The correct answer is Natural Gas.

Key Points

Therefore, the correct answer is Natural Gas.

Key Points

• The gross calorific value of a gas is the quantity of heat liberated by the combustion of a unit volume of gas.
• The net calorific value of a gas is the gross calorific value minus the latent heat in the water produced by the combustion of the hydrogen in the gas (free or combined) above atmospheric temperature. 

The correct answer is greater than 1.

Key Points

• Fast breeder reactor (FBR) which uses fast (i.e. unmoderated) neutrons to breed fissile plutonium and possibly higher transuranic from fertile uranium-238.
• The fast spectrum is flexible enough that it can also breed fissile uranium-233 from thorium.
• One measure of a reactor's performance is the "conversion ratio", defined as the ratio of new fissile atoms produced to fissile atoms consumed. 
• A breeder reactor is a nuclear reactor that generates more fissile material than it consumes i.e., the ratio of fissile material produced to fissile material consumed is greater than 1.
• When the conversion ratio is greater than 1, it is often called the "breeding ratio". 

Therefore, the correct answer is greater than 1.

Explanation:

Given Data

Efficiency, Ƞ = 20% = 20/100 = 0.20

Incident Solar Radiation, S.I  = 400 W/m²

Power = 2 kW = 2000 W

Solution

Power = Ƞ x S.I x Area

2000    = 0.20 x 400 x Area

2000    = 80 x Area

Area  = 2000 / 80

Area  = 25 m²

Hence, option 2 is the correct answer.

Calculation:

Given:

The flow of water, Q = 10 m³s^-1

Speed of water, v = 3 ms^-1

Efficiency (ɳ) = 0.6

Since, Power,

P = \( {1{} \over 2}\) Q × ɳ ×1000 × v²

P = 0.5 × 10 × 0.6 ×1000 × (3)²

P = 27000 W = 27×10³ = 27 kW

Therefore, Power, P = 27 kW

Key Points

• Wind energy harnesses the power of moving air to generate electricity.
• This form of energy is considered renewable because it relies on wind, which is a naturally occurring and inexhaustible resource.
• Unlike fossil fuels, wind energy does not emit greenhouse gases during operation, making it an environmentally friendly option.
• Wind turbines convert the kinetic energy of wind into mechanical power, which can then be converted into electricity.
• Advancements in technology have made wind energy more efficient and cost-effective, contributing to its growing adoption worldwide.

Additional Information

• Wind energy is often used in conjunction with other renewable energy sources like solar power to create a more reliable and sustainable energy grid.
• The installation of wind farms can also provide economic benefits, including job creation and local investment.
• Challenges such as noise pollution and impact on wildlife are being addressed with improved turbine designs and strategic placement.