Category: Renewable Energy Objective Questions

Geothermal Energy Multiple Choice Questions on “Types of Geothermal Resources – 1”.

1. What are the types of geothermal energy resources?
a) Hydrothermal, geo-pressurised brines, hot dry rocks, magma
b) Hydrothermal, geo-pressurised brines, hot dry rocks, sun
c) Biomass, geo-pressurised brines, hot dry rocks
d) Wind, magma, geopressurised brines, hydrothermal
Answer: a
Clarification: The four types of geothermal energy resources are hydrothermal, geopressurised brines, hot dry rocks and magma, Biomass, sun and wind are not types of geothermal energy resources.

2. What are the forms of geothermal energy?
a) Liquid and solid
b) Liquid and vapour
c) Solid and Bose-Einstein condensate
d) Plasma and liquid
Answer: b
Clarification: Geothermal energy either comes in liquid form or in vapour form. They are not solids. Bose-Einstein condensate and plasma are not forms of geothermal energy. They are states of matter.

3. What is/are the ingredient in hydrothermal plants?
a) Water
b) Hot water
c) Hot water and steam
d) Steam and water
Answer: c
Clarification: Generally, the ingredients for hydrothermal plants are hot water and steam. Both hot water and steam come together in a package. Steam cannot exists without the water being hot.

4. Which of the following naturally occurring heater is best responsible for the hot water in a geothermal site?
a) Solar heater
b) Induction stove
c) Sunlight
d) Magma
Answer: d
Clarification: Magma is mainly responsible for heating the surrounding water and generating steam in a geothermal site. Solar heater and induction stove are not natural heaters. Sunlight does not the water in a geothermal site.

5. Which of the following affect the usage of hydrothermal resources?
a) Temperature and depth of the source
b) Temperature and location of the site
c) Location of the site and depth of the source
d) Type of water and steam
Answer: a
Clarification: Temperature and depth of the source affect the application of hydrothermal resource. It does not depend on the location of the site. Water and steam do not have types.

6. Which temperature range is most suitable for directly using the hydrothermal resource? Note that “F” stands for Fahrenheit.
a) 100 – 150 degree F
b) 50 – 60 degree F
c) -100 – -90 degree F
d) -100 – 0 degree F
Answer: b
Clarification: The temperature range between 50 – 60 degree F is most suitable for directly using the hydrothermal resource. Such sources are also called as low temperature sources.

7. _________ directly use low temperature hydrothermal source.
a) Electricity generation
b) Waste treatment
c) Spas
d) Gas stove
Answer: c
Clarification: Spas directly use low temperature hydrothermal source. Other examples are heating buildings and warming fish ponds. Gas stoves use LPG. Waste treatment is not done using geothermal sources.

8. Which of the following temperature ranges is most suitable to generate electricity from hydrothermal resources? Note that “F” stands for Fahrenheit.
a) 100 – 150 degree F
b) 55 – 60 degree F
c) -200 – -90 degree F
d) 300 – 700 degree F
Answer: d
Clarification: Electricity generation requires higher temperatures to run turbines. The typical temperature range is between 300 to 700 degree F and can reach 1000 degree F as well.

9. Which of the following best indicates the electricity generation from dry steam?
a) Drilling well → steam → pipes → generator
b) Steam → drilling well → pipes → generator
c) Steam → pipes → drilling well → generator
d) Generator → steam → pipes → drilling well
Answer: a
Clarification: The steam is extracted from the drilling wells via pipes. So, the steam flows through the pipes to run the turbines of generator thereby generating electricity.

10. Which of the following best indicates the electricity generation from hot water geothermal source?
a) Drilling well → hot water → generator → steam
b) Drilling well → hot water → steam → generator
c) Generator → hot water → steam → drilling well
d) Hot water → steam → drilling well → generator
Answer: b
Clarification: Hot water geothermal reservoirs are the most common type. The hot water flows from the drilling wells through the pipe. This hot water is then vaporized to generate steam which in turn runs the turbines.

11. What is a binary cycle power plant?
a) Lower temperature hot water is used to cool a fluid which compresses
b) Higher temperature hot water is used to cool a fluid which compresses
c) Lower temperature hot water is used to heat a fluid which expands
d) Higher temperature hot water is used to heat a fluid which compresses
Answer: c
Clarification: A binary cycle power plant is used when the water is not sufficiently hot enough. So, the lower temperature hot water is used to heat a fluid which in turn expands when warmed.

12. Which of the following is used to run the turbine in a binary cycle power plant?
a) Fluid compressed due to hot water from the geothermal site
b) Hot water
c) Steam
d) Fluid expanded due to hot water from the geothermal site
Answer: d
Clarification: A binary cycle power plant uses the hot water from the geothermal site to heat a fluid which in turn expands. The turbine is powered from the expanded and pressurized fluid.

13. What are geopressurised resources?
a) Increased pressure in the geothermal reservoir
b) Increased temperature in the geothermal reservoir
c) Decreased temperature in the geothermal reservoir
d) Decreased pressure in the geothermal reservoir
Answer: a
Clarification: Geopressurized resources are formed when the geothermal reservoir is trapped by an impermeable sedimentary cap rock. This is the reason for the increase in pressure inside the reservoir.

14. The pressure inside a geothermal reservoir increases due to the weight of the sediment layer.
a) True
b) False
Answer: b
Clarification: The pressure inside a geothermal reservoir increases because of the weight and the lack of permeability of the sediment layer. This is the same sediment layer that traps the geothermal reservoir.

15. Why are geopressurized sites desirably?
a) Because they increase the energy required to pump the resource
b) Because they increase the temperature of the resource
c) Because they decrease the energy required to pump the resource
d) Because they decrease the temperature of the resource
Answer: c
Clarification: The increased pressure inside geopressurized sites reduce the load on the pump. Thus, it also reduces the amount of energy required to pump the resource. The pressure increases because of the weight and impermeability of the sediment layer.

Education & Learning Series – Geothermal Energy.

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Renewable Energy Multiple Choice Questions on “Importance of Non-Conventional Energy Sources”.

1. World Energy Needs are rising due to _________
a) deforestation
b) increasing population and Industrialization
c) inflation
d) natural calamities
Answer: b
Clarification: The increasing world population has caused the world energy needs to rise significantly. Apart from the rapid growth of industries, the formation of new ones has increased the energy needs of the world. Due to these reasons, Conventional sources of energy are not enough, and hence we need alternative energy sources.

2. Which of the following is a disadvantage of Hydro Power?
a) They cause deforestation and affect wildlife
b) They cause harmful emissions
c) They are an unstable source of energy
d) They are not suitable for long-distance electricity transmission
Answer: a
Clarification: For building Hydroelectric dams, a large area is required for which deforestation is done to clear the area which affects the local wildlife. Sometimes Dams also cause floods in Forests which damages it. Building a dam also affects the aquatic life.

3. Which of the following statement is true about conventional energy sources?
a) They cause minimum pollution
b) They are available in limited quantity
c) Coal is the most used conventional energy source in the world
d) There are sufficient reserves of Coal, Petroleum and Natural gas for the next 300 years
Answer: b
Clarification: Conventional energy sources like Coal, Petroleum, Natural gas, etc, are major causes of pollution and ozone layer depletion. There are limited reserves of conventional energy sources, which are bound to be finished. At the current rate of consumption, the approximate lifetime of the world’s petroleum, natural gas, and coal reserves are 50 years, 52.8 years, and 153 years, respectively. Oil is the most used energy source in the world. At present 31 percent of the world energy needs are fulfilled by Oil.

4. All of the conventional energy sources are Non-Renewable.
a) True
b) False
Answer: b
Clarification: Apart from Hydro Power, all other Conventional energy sources are Non-renewable. In Hydropower generation flowing water is used to generate electricity. It is considered a renewable energy source because the water cycle is constantly renewed by the sun.

5. To focus on Renewable and Other alternative sources of energy, ______ was established in March 1981 by the Government of India.
a) commission for additional sources of energy
b) commission for alternative sources of energy
c) council of scientific & industrial research
d) centre for science and environment
Answer: a
Clarification: Realizing the importance of Non-Conventional energy sources, in March 1981 the government of India established a Commission for Additional Sources of Energy (CASE), in the Department of Science and Technology. Council of Scientific & Industrial Research (CSIR) was established in September 1942 to bring Science and Technology to India. CSE (Centre for Science and Environment) was established in 1980 and works on environment-development issues in India.

6. IREDA was developed by the Government of India _______
a) to implement more efficient methods for using Conventional Energy sources
b) to promote the Development of Non-Conventional Energy Sources
c) to develop Nuclear Energy in India
d) to control pollution
Answer: b
Clarification: Indian Renewable Energy Development Agency Ltd (IREDA) was established in 1987 to promote the use of Non-Conventional sources of energy. It is operated by the Ministry of New and Renewable Energy (MNRE).

7. Apart from supplying energy, fossil fuels are used for_________
a) storing energy in solar ponds
b) drying Vegetables
c) rotating turbine in Hydro Power plants
d) manufacture of Organic Chemicals
Answer: d
Clarification: Solar pond collects thermal energy from sunlight. The salt content of the pond increases with depth. It doesn’t require any fuel for storing energy. Apart from fulfilling energy needs, fossil fuels are also used as feedstock materials for the manufacture of organic chemicals. Solar dryers are used to dry foods i.e. Fruits, Vegetables, etc. In Hydroelectric power plants, turbines are rotated by the Kinetic Energy of water.

8. The only country having a full-fledged ministry for Development of New and Renewable Resources is _____
a) India
b) Bangladesh
c) USA
d) China
Answer: a
Clarification: India is the only country having a full-fledged ministry devoted to Developing New and Renewable Energy Sources. Ministry of New and Renewable Energy or MNRE is a ministry of the Government of India. The ministry was established as the Ministry of Non-Conventional Energy Sources in 1992.

9. CASE was established after the Oil Crisis of 1973.
a) True
b) False
Answer: a
Clarification: The Energy Crisis of the 1970s i.e. Oil crisis of 1973 and Energy Crisis of 1979 caused a shortage of petroleum (and other commonly used sources) and elevation in its price. This led to the establishment of the Commission for Additional Sources of Energy (CASE) in the Department of Science & Technology (India) in March 1981. It involved the formulation of policies, their implementation, and Research and Development in the field of New and Renewable energy sources.

10. Which of the following schemes was launched by MNRE?
a) MNREGA
b) UJJWALA
c) KUSUM
d) JWALA
Answer: c
Clarification: Ministry of New and Renewable Energy(MNRE) launched the Kisan Urja Suraksha evem Utthan Mahabhiyan (KUSUM) scheme for farmers for installation of solar pumps and grid-connected solar and other renewable power plants in the India. This scheme was launched with the aim to promote solar farming in India. Its launch was approved on 19 February 2019 by the Cabinet Committee on Economic Affairs(CCEA).

Solar Energy Multiple Choice Questions on “Solar Time (Locał Apparent Time)”.

1. What is solar time?
a) Calculation of passage of time based on sun’s position in sky
b) Calculation of passage of time based on moon’s position in sky
c) A unit that measures astronomical time
d) A reference unit for time
Answer: a
Clarification: Solar time is the calculation of passage of time based on sun’s position in sky. It is not calculated based on moon’s position. In astronomy, if required, time is measured in terms of speed of light.

2. What is the fundamental unit of solar time?
a) Seconds
b) Day
c) Hour
d) Meter
Answer: b
Clarification: The fundamental unit of time is day. Meter is not a measurement of time. It is a unit and measurement of distance.

3. What are the two types of solar time?
a) Fundamental solar and multi-solar time
b) Apparent and diurnal solar time
c) Apparent solar time and mean solar time
d) Mean solar time and single-solar time
Answer: c
Clarification: The two types of solar time are apparent solar time and mean solar time. Fundamental solar time, multi-solar time and single-solar time do not exist.

4. What is apparent time also known as?
a) Clock time
b) Revolution time
c) Lunar time
d) Sundial time
Answer: d
Clarification: Apparent time is also known as sundial time. Lunar time is basically the length of one day on moon with respect to earth. Revolution time depends on the speed of revolving body and the distance between body around which it revolves and itself.

5. Which of the following is the simplest sundial?
a) A tall pole casting a shadow whose length and position varies with sun’s position
b) A tall pole
c) A tall pole casting a shadow that varies with moon’s position
d) A stone slab
Answer: a
Clarification: Among the above options, a tall pole casting a shadow is the simplest sundial. It should be noted that both, the length and position of the shadow must vary with sun’s position. A tall pole casting a shadow that varies with moon’s position is not a sundial.

6. What is mean solar time also known as?
a) Rotation time
b) Clock time
c) Lunar time
d) Sundial time
Answer: b
Clarification: Mean solar time is also known as clock time. Apparent solar time is also known as sundial time. Lunar time is the length of a day on moon as compared to earth. Rotation time is the time a body takes to rotate about an axis.

7. Solar time is _____ clock time in December and ____ clock time in September.
a) same as, same as
b) less, more
c) more, less
d) more, same as
Answer: c
Clarification: Solar time is more than clock time in December. However, it is less than clock time in September. It is almost same as the clock time during the other months.

8. Why is does the solar time vary in September and December?
a) Because of earth-moon distance
b) Because of earth-moon gravitational force
c) Because of eccentricity of sun-moon orbit
d) Because of eccentricity of earth-sun orbit
Answer: d
Clarification: Solar time varies because of the eccentricity of earth-sun orbit. Earth’s orbit around the sun is elliptical and not perfectly circular. The variation in solar time does not depend on sun-moon and earth-moon distance/orbit.

9. The clock running at a constant (say, a pendulum clock) rate _____
a) cannot follow the sun
b) always follows the sun
c) follows the sun randomly
d) follows the moon
Answer: a
Clarification: The clock running at a constant (say, a pendulum clock) rate cannot follow the sun. This is because of the elliptical nature of earth’s orbit and the tilt of earth’s axis.

10. What does a clock running at a constant rate follow?
a) Moon
b) Imaginary mean sun
c) Actual sun
d) Real mean sun
Answer: b
Clarification: A clock running at constant rate does not and cannot follow the actual sun. Instead, it follows an imaginary mean sun. This imaginary sun moves at a constant rate along a celestial equator. The motion is such that it matches the real sun’s average clock over the period of a year.

11. What is apparent solar day?
a) Interval between sunrise and sunset of a normal day
b) Interval between two successive returns of sun on equator
c) Interval between two successive returns of sun on local meridian
d) Imaginary solar day
Answer: c
Clarification: The interval between two successive returns of sun on local meridian is called apparent solar day. The apparent motion of the actual sun is governs apparent solar time.

12. Which of the following describes the elliptical nature of earth’s orbit?
a) Apparent solar time
b) Sundial
c) Maxwell’s laws
d) Kepler’s laws
Answer: d
Clarification: Kepler’s laws describe the elliptical nature of earth’s orbit. Maxwell’s laws are related to electrodynamics. Sundial is an instrument used to measure apparent solar time.

13. The hour angle of the mean sun plus 12 hours is _______
a) mean solar time
b) angled solar time
c) offset solar time
d) apparent solar time
Answer: a
Clarification: The hour angle of the mean sun plus 12 hours is called the mean solar time. The 12 hour offset is used to ensure that each day starts at midnight for civil purposes. The hour angle or mean sun is measured from local meridian.

14. Solar time is 21 seconds less than clock time in September and 29 seconds more than clock time in December.
a) True
b) False
Answer: a
Clarification: Solar time is 21 seconds less than clock time in September and 29 seconds more than clock time in December. This is due to the eccentricity of earth’s orbit around the sun i.e. it is not perfectly circular.

15. The inclination of earth’s axis also contributes towards variation in solar time.
a) True
b) False
Answer: a
Clarification: Along with the elliptical nature of earth’s orbit around sun, the inclination of earth’s axis also contributes towards variation in solar time. Earth’s axis is not perpendicular to the plane of orbit.

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Solar Energy Multiple Choice Questions on “Solar Dryer”.

1. What is solar dryer?
a) Use solar energy to dry substances
b) Use solar energy to evaporate water and collect it within the same closed system
c) Use solar energy to evaporate water and collect its condensate within the same closed system
d) Use solar energy to dry liquids

Answer: a
Clarification: Solar dryer are devices that use solar energy to dry substances. Devices that use solar energy to evaporate water and collect its condensate within the same closed system are called solar stills.

2. What is the most popular use of solar dryer?
a) Water
b) Food
c) Chemicals
d) Industrial substances

Answer: b
Clarification: Popularly, solar dryers are used to dry foods. If not the, it is one of the most common application of solar dryers. Since the question specifies most popular, food is the answer.

3. What are the two general types of solar dryers?
a) Direct and active
b) Indirect and passive
c) Direct and indirect
d) Box like and cone shaped

Answer: c
Clarification: The two general types of solar dryers are direct and indirect. Active and passive are types of solar stills. Box like and cone shaped are some of the basic configurations of solar stills.

4. What is the basic working principle of direct solar dryers?
a) Direct exposure of substance to fire
b) Direct use of sunlight to start a heater which is then used to dry the substance
c) Indirect exposure of substance to sunlight
d) Dehydrating the substance by directly exposing to sunlight

Answer: d
Clarification: The basic working principle of direct solar dryers is that they directly expose the substance to sunlight. By directly exposing the substance, they dehydrate the substance. A heater may or may not be used in a solar dryer.

5. Which of the following best indicates an example of direct solar dryer?
a) Drying wet clothes on wired lines
b) Using the dryer of a washing machine
c) Using an electric heater
d) Using a solar heater

Answer: a
Clarification: Drying wet clothes on wired lines is an example of direct solar dryer. Many countries including India still use this traditional method to dry clothes as it is cheap and natural. Electric and solar heaters are not solar dryers.

6. How do wet clothes laid on wired lines dry under sunlight?
a) Wind blows to accumulate more air consisting moisture near the clothes
b) Wind blows away the moisture near the wet clothes air exposing them to fresh air and sunlight
c) Sunlight continuously evaporates water in wet clothes without any assistance from wind
d) Wind blows away the moisture near the wet clothes air exposing them to fresh air

Answer: b
Clarification: Both sunlight and wind assist drying of wet clothes laid on wired lines. As the sun evaporates water from the clothes, moisture content in the surrounding air increases. Wind blows away this moisture saturated air and exposes to the clothes to fresh air and sunlight. The process repeats thereby drying the wet clothes over time.

7. Which of the following surface is best suited to absorb sunlight?
a) White surface
b) Red surface
c) Black surface
d) Silver surface

Answer: c
Clarification: A black surface or a black coated surface is best suited to absorb sunlight. This is supported by the concept of black body. A black body is an idealized physical body that absorbs all incident electromagnetic radiation.

8. How does an indirect solar dryer work?
a) By directly exposing the substance to sunlight
b) By using an electrical heater
c) By heating the incoming air with the help of a black surface
d) By using fire

Answer: d
Clarification: An indirect solar dyer heats the incoming air with the help of a black surface. Then this heated air is passed over the substance to be dried thereby drying the substance.

9. Why is direct solar dryer harmful for food?
a) Because direct sunlight could chemically alter some food items
b) Because direct sunlight dries the food
c) Because direct solar dryer does not cover the food
d) Because of contaminants brought by wind

Answer: a
Clarification: A major problem with a direct solar dryer is that it can harm the food. This is because the sunlight could chemically alter some food item and make them less appetizing. Contamination due to wind is also a problem but it is not as bad as chemical alteration.

10. Indirect solar dryers protect the food.
a) False
b) True

Answer: b
Clarification: Indirect solar dryers protect the food from directly exposing it to sunlight. Since they heat the incoming air they do not directly expose the food to sunlight. This prevents chemical alteration of food items.

11. _______ are used as air exhausts in indirect solar dryers.
a) Turbines
b) Ceiling fans
c) Chimneys
d) Table fans

Answer: c
Clarification: Chimneys are used as air exhausts in indirect solar dryers. They let the moisture containing air pass out of the chamber thereby making room for freshly heated air.

12. A glass cover _______ solar dryers.
a) decreases the efficiency of
b) is not used in
c) does not affect the efficiency of
d) increases the efficiency of

Answer: d
Clarification: A glass cover increases the efficiency of solar dryers. Sometimes, direct solar dryers are equipped with glass covers to trap more heat thereby increasing the efficiency of the system.

13. Which of the following best explains the increment in efficiency of a glass covered solar dryer?
a) Greenhouse effect
b) Greenhouse gas
c) Climate change
d) Thermohaline circulation

Answer: a
Clarification: Greenhouse effect best explains the increment in efficiency of a glass covered solar dryer. Greenhouse effect is the process of increasing the temperature of a chamber covered with glass by trapping sun’s heat within the chamber.

14. Which of the following is an example of indirect solar dryer?
a) Wet clothes laid on wired lines
b) Solar cabinet dryer
c) Solar tunnel dryer
d) Biomass cabinet dryer

Answer: b
Clarification: Solar cabinet dryer is an example of indirect solar dryer. Wet clothes laid on wired lines is an example of direct solar dryer. Solar tunnel dryer and biomass cabinet dryer are not examples of indirect solar dryers.

15. Indirect solar dryers work on natural air convection.
a) True
b) False

Answer: a
Clarification: Indirect solar dryers work on natural air convection. This is because the incoming air is heated by a black surface. As the air is heated, it rises thereby giving room for the heavier colder air to get heated.

Wind Energy Assessment Questions on “Effects of Wind Speed and Grid Condition (System Integration) – 1”.

1. Why is the energy output of wind power plant variable?
a) Wind speed is variable
b) Wind speed is an unknown constant
c) Wind speed is known constant
d) Poor equipment is used

Answer: a
Clarification: The energy output of any wind power plant (WPP) is variable because the wind speed is variable. The equipment used in power plant is designed to deal with such variability and uncertainty.

2. Which of the following is a reason for variable wind speed?
a) Water
b) Earth’s rotation
c) Electrons
d) Fans

Answer: b
Clarification: Day and night cycle caused by earth’s rotation and seasonal changes due to tilt axis of earth cause changes in wind speed. Water, electrons and fans do not affect wind speed.

3. What is grid integration of wind energy?
a) Planning the connection of wind power plant to the grid
b) Physical connection of wind power plant to the grid
c) Energy sent from grid to run the wind turbines
d) Collection of all activities related to connecting wind power plants to the grid

Answer: d
Clarification: Grid integration of wind energy is simply the collection of all activities related to connecting wind power plants to the grid. The wind power plant sends energy to the grid. It does not consume energy from the grid.

4. Which of the following depicts the correct order of the stages involved in grid integration of wind energy?
a) System operations → physical connection → planning
b) Planning → system operations → physical connection
c) Planning → physical connection → system operations
d) Physical connection → planning → system operations

Answer: c
Clarification: Grid integration of wind energy consists of three stages starting with planning the connection. After laying out the plan, the power plant is physically connected to the substation (grid). Lastly, the functioning of each system is handled under systems operation.

5. What are the two types of planning activities related to grid integration?
a) Network-wide and project-specific
b) BJT and MOSFET
c) Rotor and shaft
d) Low power and high power designs

Answer: a
Clarification: The two types of planning activities related to grid integration are network-wide and project-specific activities. BJT and MOSFET are electronic/electrical devices (components). Rotor and shaft are used in a rotating mechanism. Low power and high power designs are circuit design specifications.

6. Which of the following best describes network-wide planning activity in grid integration?
a) Planning activities related to a unique wind project
b) Planning activities for all the future wind power plants
c) Planning activities for a telecommunication system
d) Planning activities for the maintenance of the existing wind power plants

Answer: b
Clarification: Network-wide plans are laid out for all the future wind power plants. Planning activities for a telecommunication system are not related to grid integration of wind energy. Maintenance of existing wind power plants is covered in the previous network-wide plan.

7. Network-wide plans in wind energy grid integration include _______
a) system impact studies done for a specific wind project
b) materials used to manufacture wind turbine blades
c) developing grid code
d) solar panel manufacturing plant

Answer: c
Clarification: Network-wide plans include development of grid code, network-wide system integration studies with scenarios for different levels of wind penetration and system operation studies. They are not done for a specific wind project.

8. What is project specific planning in wind energy grid integration?
a) Planning activities for a solar panel system
b) Planning activities for all the future wind power plants
c) Planning activities related to a unique wind project
d) Planning activities for the maintenance of the existing thermal power plants

Answer: c
Clarification: Project specific planning activities in wind energy grid integration are planning activities related to a unique wind project. They include system impact studies done for a specific wind project. The input for this type of study is the wind power plant which is being studied.

9. In a substation, the wind power plant line is connected to a _______ voltage bus bar.
a) high
b) low
c) mini
d) medium

Answer: d
Clarification: In a substation, the wind power plant line is connected a medium voltage bus bar. A medium voltage bus bar is used for medium voltages – 10kV to 50kV. At the wind turbine generator, this bar is connected to a step up transformer which steps up the output of the generator from 0.69kV to 11kV or 33kV.

10. Which of the following are a few primary tests performed after commissioning phase in the physical connection stage?
a) Switch-gear functioning and quality parameters
b) Feathering
c) Wind turbine blade tests
d) Rotor and shaft tests

Answer: a
Clarification: Testing the functioning of switch-gear, quality parameters like harmonics and flicker, proper start-up and shut down are crucial during grid integration. Feathering of blades is done to prevent the blades from being damaged by storm winds. Wind turbine blade, rotor and shaft tests do not come under grid integration tests.

11. Which of the following are impacts of grid integration of wind power plant?
a) Day-ahead unit commitment process
b) Day-ahead unit commitment process, economic dispatch process
c) Generator types
d) Rotor and shaft tests

Answer: b
Clarification: The unit commitment process is cost-effective combination of generating units to meet forecasted load and reserve requirements, while adhering to generator and transmission constraints. Economic dispatch is the optimization of production from generators to minimize cost of generation while meeting all the constraints. In most grids, wind energy has the highest priority due to its low marginal costs.

12. Which of the following is/are good practices for grid integration of wind power plant?
a) Day-ahead unit commitment process
b) Day-ahead unit commitment process, economic dispatch process
c) Optimized transmission from resources-rich areas to load, flexible generation
d) Rotor and shaft tests

Answer: c
Clarification: Optimizing transmission from resource-rich areas to load saves both, power and costs. Using the under-utilized line to transmit power instead of setting a new transmission line is an example of optimization. Flexible power generation helps meeting in varying power demands.

13. What is a grid code for wind energy integration?
a) A binary code
b) A hexadecimal code
c) A code of conduct
d) A rulebook specifying generator properties

Answer: d
Clarification: A grid code for integration is a rulebook that specifies properties of generators and other equipment used to connect to the grid. The equipment must satisfy these properties to ensure reliable and safe operation.

14. What are the types of grid integration costs?
a) Transmission extension, volatility balancing, covering peak load
b) Marginal cost
c) Fixed cost
d) Fundamental Analysis

Answer: a
Clarification: Grid integration costs are divided into three categories – transmission extension, balancing of increased volatility in grid and covering the peak load. The other options are various terms used in economics and finance to define different types of costs. They are not particularly related to grid integration.

15. What is a power flow study in wind energy integration?
a) A binary code
b) Determines flow of electrical energy from generators to consumers
c) Determines flow of electrical energy from generators to consumers meeting line loading requirements
d) A study specifying generator properties

Answer: c
Clarification: A power flow study in wind energy integration determines flow of electrical energy from generators to consumers meeting line loading requirements and all grid code requirements. It is performed using various power systems modelling software like PSS/E and ETAP.

Geothermal Energy online test on “Types of Geothermal Resources – 2”.

1. Which of the following is a type of high temperature geothermal resource?
a) Dry steam
b) Dry water
c) Wet steam
d) Water
Answer: a
Clarification: High temperature hydrothermal resource is used to produce electricity. The two main types of high temperature hydrothermal resources are dry steam and hot water.

2. Dry steam is _________ dominated.
a) liquid
b) vapour
c) solid
d) plasma
Answer: b
Clarification: Dry steam is a type of high temperature hydrothermal resource. It is vapour dominated. It is mainly used to generate electricity.

3. Hot water is _________ dominated.
a) vapour
b) nitrogen
c) liquid
d) Bose-Einstein condensate
Answer: c
Clarification: Hot water is liquid dominated high temperature hydrothermal resource. Like dry steam, it is used to generate electricity. Unlike low temperature resources, it cannot be used directly.

4. Which of the following is also called as a flash steam plant?
a) Low temperature hydrothermal resource
b) Dry steam
c) Hydrogen
d) Hot water
Answer: d
Clarification: Hot water is a high temperature hydrothermal resource. It is also called as flash steam plant because the hot water is first converted to steam. This steam is used to drive the turbines to generate electricity.

5. What is hot dry rock geothermal resource made of?
a) Granite
b) Soil
c) Solid carbon dioxide
d) Liquid nitrogen
Answer: a
Clarification: Hot dry rock is made up of granite. It is a unique geothermal resource that lacks stored fluid and has extremely low permeability. Fracture creation is required for commercial applications.

6. Which of the following fracture creation techniques is/are used in hot dry rock geothermal resource?
a) Condensation and hydrofracking
b) Hydrofracking and hydroshearing
c) Hydroshearing and distillation
d) Hydrofracking and combustion
Answer: b
Clarification: Hydrofracking and hydroshearing are the two commonly used fracture creation techniques for practical applications hot dry rock. Condensation, distillation and combustion are not fracture creation techniques.

7. What is the difference between enhanced geothermal system and hot dry rock?
a) Lack of fluid permeability
b) Fluid permeability
c) Presence of fluid
d) Presence of rocks
Answer: c
Clarification: The main difference between enhanced geothermal system and hot dry rock is the presence of fluid. Enhanced geothermal system contains hot fluid but hot dry rock does not or contains negligible amounts.

8. What is the similarity between enhanced geothermal system and hot dry rock?
a) Magma
b) Presence of steam
c) Presence of fluid
d) Lack of fluid permeability
Answer: d
Clarification: The main similarity between the two is that both lack fluid permeability. Magma is not the right option because it is present irrespective of the resource. In fact, it heats the resource. Both the resources lack steam.

9. Enhanced geothermal resource is man-made.
a) True
b) False
Answer: a
Clarification: Enhanced geothermal resource is a man-made reservoir. It is created where there is hot rock but insufficient or little permeability of the fluid.

10. Deep hydrothermal systems are found at a depth of ______
a) 1km
b) 2.5 – 5km
c) 10km
d) 1 – 2km
Answer: b
Clarification: Deep hydrothermal systems are found at a depth of 2.5 – 5km. The surrounding regions do not have elevated geothermal temperature gradients and the temperature range is between 120 – 140 degree Celsius.

11. What are deep hydrothermal systems?
a) Hot dry rock
b) Magma
c) Permeable and fluid saturated region
d) Impermeable and fluid saturated region
Answer: c
Clarification: Deep hydrothermal systems consists of permeable and saturated fluid in the surrounding region at a depth of 2.5 – 5km below the earth. The region is surrounded by magma and can be used to generate electricity.

12. Which of the following is responsible for the volcanic geothermal heat?
a) Water
b) Hot dry rock
c) Carbon dioxide
d) Supercritical water
Answer: d
Clarification: Supercritical water is responsible for the volcanic geothermal heat. The energy obtained from this supercritical water is much higher than conventional geothermal steam. Carbon dioxide does not contribute to any geothermal resource. Hot dry rock is a geothermal resource found beneath earth’s surface and not near volcanoes.

13. Supercritical water is a liquid.
a) False
b) True
Answer: a
Clarification: Supercritical water is a unique state of water where it neither behaves as a true liquid nor as a true gas. It is capable of generating upto 10 times more power than conventional geothermal sources.

14. Where is geothermal energy from volcanoes being harvested?
a) United States
b) Iceland
c) Iran
d) Greenland
Answer: b
Clarification: Iceland is a nation built on about 130 volcanoes. It rests above a divergent plate boundary which brings continuous supply of hot and fresh magma from the mantle. Iceland Deep Drilling Project (IDDP) is the most famous amongst all the other projects.

15. Geothermal power plants are very good sources for baseload power.
Note – Baseload power is power that electric utility companies must deliver all day long.
a) True
b) False
Answer: a
Clarification: Geothermal power plants are very good sources for baseload power. Except for the high initial costs, they produce electricity very cheaply – 4.5 to 7 cents per KWh. In fact, baseload geothermal plants sell electricity all the time even when during high demand.

Education & Learning Series – Geothermal Energy.

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