Q.1 What is the primary purpose of a battery in a smart grid?
To generate electricity
To store excess power
To measure voltage
To cool down the grid
Explanation - Batteries act as energy storage devices, absorbing surplus electricity during low demand and supplying it when demand rises, thus stabilizing the grid.
Correct answer is: To store excess power
Q.2 Which of these is a common type of rechargeable battery used in electric vehicles?
Alkaline
Lead‑acid
Lithium‑ion
Nickel‑metal hydride
Explanation - Lithium‑ion batteries offer high energy density and are widely used in EVs for their lightweight and long cycle life.
Correct answer is: Lithium‑ion
Q.3 Why do smart grids use communication networks?
To keep the wires hidden
To share data about power usage
To turn on the lights automatically
To entertain users
Explanation - Communication links enable real‑time monitoring and control, allowing utilities to balance supply and demand efficiently.
Correct answer is: To share data about power usage
Q.4 What is a ‘grid‑scale battery’?
A small battery for phones
A battery used in a single house
A large battery that stores electricity for the whole grid
A battery that runs on solar panels only
Explanation - Grid‑scale batteries are large installations that help smooth out supply variations across many users.
Correct answer is: A large battery that stores electricity for the whole grid
Q.5 Which unit measures electrical energy?
Volt
Watt
Watt‑hour
Ampere
Explanation - Watt‑hour (Wh) quantifies the amount of energy used or stored, while volts and amperes measure voltage and current.
Correct answer is: Watt‑hour
Q.6 Which technology helps batteries know when to charge or discharge?
Smart meters
Smart thermostats
Smart refrigerators
Smart phones
Explanation - Smart meters relay real‑time consumption data to the grid, enabling optimal battery operation.
Correct answer is: Smart meters
Q.7 What does ‘frequency regulation’ mean in a smart grid?
Changing how often lights blink
Keeping the grid’s electrical frequency steady
Adjusting the speed of the internet
Measuring how fast batteries charge
Explanation - Frequency regulation ensures the grid runs at the correct 50 or 60 Hz, preventing outages.
Correct answer is: Keeping the grid’s electrical frequency steady
Q.8 Which of these is NOT a type of energy storage?
Pumped hydro
Flywheel
Solar panels
Compressed air
Explanation - Solar panels generate electricity; they are not storage devices. Pumped hydro, flywheels, and compressed air store energy.
Correct answer is: Solar panels
Q.9 How do batteries help reduce electricity bills for homeowners?
By making lights brighter
By storing cheap nighttime energy for use during peak hours
By increasing the power supply to the house
By charging more devices
Explanation - Storing low‑cost energy for later use allows users to avoid high peak‑time rates.
Correct answer is: By storing cheap nighttime energy for use during peak hours
Q.10 What is a common challenge with battery storage in smart grids?
They always explode
They can lose capacity over time
They are invisible
They are too cheap
Explanation - Batteries degrade with each charge‑discharge cycle, reducing their effective storage capacity.
Correct answer is: They can lose capacity over time
Q.11 Which communication protocol is often used for smart meter data?
Bluetooth
Wi‑Fi
DLMS/COSEM
Ethernet
Explanation - DLMS/COSEM is a standard for data exchange between meters and utility systems.
Correct answer is: DLMS/COSEM
Q.12 What does ‘energy arbitrage’ mean?
Buying cheap power and selling expensive power
Buying cheap power and storing it for later use
Trading energy with neighbors
Using energy at all times
Explanation - Energy arbitrage exploits price differences by storing energy when it's cheap and using it when it's expensive.
Correct answer is: Buying cheap power and storing it for later use
Q.13 Which is a benefit of using hydrogen as energy storage?
It is cheap to produce
It can store large amounts of energy over long periods
It does not need any equipment
It is visible to the naked eye
Explanation - Hydrogen can be produced from excess renewable power and stored for long durations, making it suitable for seasonal storage.
Correct answer is: It can store large amounts of energy over long periods
Q.14 Which of these is NOT a communication technology for smart grids?
PLC (Power Line Communication)
Wi‑Fi Mesh
Fiber Optic
USB cable
Explanation - USB cables are for data transfer between devices, not for wide‑area grid communication.
Correct answer is: USB cable
Q.15 What does the term ‘cyber‑physical system’ refer to in smart grids?
A computer that can also cook meals
An integrated system combining physical components and digital control
A system that replaces all physical meters
A new type of smartphone
Explanation - Cyber‑physical systems merge the physical power network with cyber elements such as sensors and communication.
Correct answer is: An integrated system combining physical components and digital control
Q.16 What is the main purpose of a flywheel in energy storage?
To store electricity as mechanical energy
To generate wind power
To cool down batteries
To charge phones
Explanation - Flywheels store kinetic energy by spinning at high speeds; the energy can be released as electricity when needed.
Correct answer is: To store electricity as mechanical energy
Q.17 Which of these is an example of a distributed energy resource (DER)?
A 400 MW coal plant
A rooftop solar panel system
A national transmission line
A submarine cable
Explanation - DERs are small‑scale power sources located near consumers, such as rooftop solar or home batteries.
Correct answer is: A rooftop solar panel system
Q.18 Which device can convert stored energy back into usable electricity?
A solar panel
An inverter
A transformer
A switch
Explanation - An inverter changes direct current (DC) from storage devices into alternating current (AC) used in homes.
Correct answer is: An inverter
Q.19 Which factor influences the lifespan of a lithium‑ion battery?
The color of its casing
Its temperature during use
The brand of charger
The number of sockets it plugs into
Explanation - Higher operating temperatures accelerate chemical degradation, shortening battery life.
Correct answer is: Its temperature during use
Q.20 What does a ‘smart inverter’ do in a solar system?
It turns solar panels into batteries
It manages power flow between panels, battery, and grid
It makes panels brighter
It heats up the house
Explanation - Smart inverters optimize the use of generated solar power and coordinate with energy storage.
Correct answer is: It manages power flow between panels, battery, and grid
Q.21 Which type of battery uses a salt‑water electrolyte instead of a liquid acid?
Lead‑acid
Lithium‑ion
Sodium‑sulfur
Alkaline
Explanation - Sodium‑sulfur batteries use molten salt and sulfur, offering high energy density for grid storage.
Correct answer is: Sodium‑sulfur
Q.22 Why are communication protocols important for battery management systems?
They keep the battery bright
They ensure data from sensors reach control units accurately
They prevent the battery from overheating
They make the battery silent
Explanation - Protocols standardize how data is transmitted, allowing precise control of charging and discharging.
Correct answer is: They ensure data from sensors reach control units accurately
Q.23 Which of the following is a real advantage of using supercapacitors for energy storage?
Very long cycle life
Low cost
High energy density
Can operate at very high temperatures
Explanation - Supercapacitors can endure millions of charge cycles, though they store less energy than batteries.
Correct answer is: Very long cycle life
Q.24 What is a key challenge when integrating many small batteries into a grid?
Synchronizing them all
Finding enough space for them
Keeping them all hot
Making them all look the same
Explanation - Distributed batteries must coordinate to prevent voltage or frequency issues across the network.
Correct answer is: Synchronizing them all
Q.25 What role does artificial intelligence (AI) play in smart grid energy storage?
It replaces all batteries
It predicts demand and optimizes storage use
It paints the grid walls
It charges batteries automatically
Explanation - AI algorithms analyze data to forecast load patterns, maximizing the efficiency of storage resources.
Correct answer is: It predicts demand and optimizes storage use
Q.26 What does the term 'grid parity' refer to?
When solar panels are as cheap as the grid
When the grid has a perfect shape
When all houses have identical wiring
When the grid runs on pure electricity
Explanation - Grid parity is achieved when renewable electricity costs less than grid-supplied power, encouraging adoption.
Correct answer is: When solar panels are as cheap as the grid
Q.27 Which of the following is NOT typically considered a storage medium for electricity?
Hydrogen gas
Compressed air
Magnetic fields
Wind turbines
Explanation - Wind turbines generate power; they do not store it. Storage mediums convert power into a storable form.
Correct answer is: Wind turbines
Q.28 What is the function of a 'charge controller' in a battery system?
It charges the battery at a safe rate
It cools the battery
It discharges the battery instantly
It monitors the battery color
Explanation - Charge controllers regulate voltage and current to protect batteries from overcharging.
Correct answer is: It charges the battery at a safe rate
Q.29 Which communication technology uses existing power lines for data transmission?
Power Line Communication (PLC)
Bluetooth
Wi‑Fi
NFC
Explanation - PLC embeds data signals onto electrical wires, enabling network connectivity without extra cables.
Correct answer is: Power Line Communication (PLC)
Q.30 Which of these is a key advantage of using grid‑scale battery storage?
Immediate response to frequency changes
Unlimited capacity
Zero cost
No maintenance required
Explanation - Batteries can discharge or absorb power in milliseconds, aiding grid stability during disturbances.
Correct answer is: Immediate response to frequency changes
Q.31 What is the main difference between 'energy' and 'power'?
Energy is quantity, power is rate
Energy is measured in watts, power in watt‑hours
They are the same
Energy is heavier than power
Explanation - Energy (e.g., watt‑hours) is total amount consumed; power (e.g., watts) is how fast it is used.
Correct answer is: Energy is quantity, power is rate
Q.32 Which protocol is commonly used for secure communication in smart grids?
TLS/SSL
HTTP
FTP
Telnet
Explanation - TLS/SSL provides encryption and authentication, protecting data exchanges in the grid.
Correct answer is: TLS/SSL
Q.33 Why might a utility install a 'pumped hydro storage' plant?
To generate hydroelectric power continuously
To store excess energy by moving water between reservoirs
To reduce water usage
To produce hydrogen fuel
Explanation - Pumped hydro stores energy as potential energy in an upper reservoir, releasing it by letting water flow back down.
Correct answer is: To store excess energy by moving water between reservoirs
Q.34 Which of the following best describes 'load shifting'?
Moving the load to a different grid
Using stored energy to supply power during high‑demand periods
Shifting the physical location of a house
Reducing the weight of the load
Explanation - Load shifting involves using storage to avoid peak‑time demand, saving costs and reducing strain on the grid.
Correct answer is: Using stored energy to supply power during high‑demand periods
Q.35 Which device measures the voltage and current of a battery during charging?
Multimeter
Thermometer
Barometer
Speedometer
Explanation - A multimeter can test electrical parameters to ensure proper charging and prevent damage.
Correct answer is: Multimeter
Q.36 Which of these is a benefit of using solid‑state batteries?
They are made of solid rock
They have higher energy density and safety
They are cheaper than lead‑acid batteries
They use water as electrolyte
Explanation - Solid‑state batteries replace liquid electrolytes with solid materials, improving performance and reducing fire risk.
Correct answer is: They have higher energy density and safety
Q.37 What is a typical use case for a flywheel energy storage system in a power grid?
Long‑term seasonal storage
Quick frequency regulation
Generating solar power
Cooling the grid
Explanation - Flywheels respond in milliseconds, ideal for smoothing rapid frequency fluctuations.
Correct answer is: Quick frequency regulation
Q.38 What does 'smart charging' of electric vehicles involve?
Charging only when the battery is full
Charging at the lowest grid price times and using V2G to supply power back
Charging at a constant rate regardless of the grid
Charging only through solar panels
Explanation - Smart charging optimizes cost and grid support, sometimes feeding energy back via Vehicle-to-Grid (V2G).
Correct answer is: Charging at the lowest grid price times and using V2G to supply power back
Q.39 Which of the following best describes a 'distributed battery system'?
A single giant battery in the middle of the city
Multiple small batteries placed near consumers
A battery that is distributed by a company
A battery that distributes water
Explanation - Distributed batteries reduce transmission losses and improve resilience by being located close to load centers.
Correct answer is: Multiple small batteries placed near consumers
Q.40 What is the purpose of an 'energy management system (EMS)' in a smart grid?
To paint the grid in bright colors
To monitor and optimize energy flows and storage
To store batteries only
To generate electricity
Explanation - EMS uses data and algorithms to control generation, storage, and consumption for efficiency.
Correct answer is: To monitor and optimize energy flows and storage
Q.41 Which factor most significantly limits the deployment of grid‑scale batteries?
Their bright color
The cost and availability of materials
The lack of batteries in the market
The absence of storage need
Explanation - Materials such as lithium and cobalt can be expensive and scarce, influencing large‑scale adoption.
Correct answer is: The cost and availability of materials
Q.42 What does V2G stand for in the context of electric vehicles?
Vehicle to Grid
Voltage to Gas
Virtual to Generation
Voltage to Ground
Explanation - V2G allows vehicles to supply stored electricity back to the grid during peak demand.
Correct answer is: Vehicle to Grid
Q.43 Which of these communication methods is best suited for wide‑area coverage of a smart grid?
Bluetooth Low Energy
Zigbee
Cellular (4G/5G)
Infrared
Explanation - Cellular networks provide large coverage areas and high data rates, ideal for grid management.
Correct answer is: Cellular (4G/5G)
Q.44 What is the main advantage of using compressed air energy storage (CAES) in large grids?
It requires no water
It can store energy for hours or days
It produces hydrogen automatically
It is cheaper than any other storage
Explanation - CAES uses pressurized air in underground caverns, providing long‑duration seasonal storage.
Correct answer is: It can store energy for hours or days
Q.45 Which of the following is NOT a common energy storage technology?
Li‑ion batteries
Pumped hydro
Solar cells
Flywheel
Explanation - Solar cells generate electricity, they do not store it. Storage technologies convert electricity to other forms.
Correct answer is: Solar cells
Q.46 What is the role of 'frequency droop' in grid stability?
To keep frequency constant by adjusting generator output
To drop the grid's frequency randomly
To increase voltage
To control lighting color
Explanation - Frequency droop is a control strategy where generators automatically reduce output when frequency rises.
Correct answer is: To keep frequency constant by adjusting generator output
Q.47 Which communication protocol is widely adopted for smart meters in Europe?
Z-Wave
IEC 61850
MQTT
Modbus
Explanation - IEC 61850 is an international standard for communication in substations and smart grids.
Correct answer is: IEC 61850
Q.48 What is the primary benefit of using hybrid energy storage systems?
They are cheaper to build
They combine strengths of different storage types to improve overall performance
They require no maintenance
They are lighter than single‑type systems
Explanation - Hybrid systems (e.g., battery + flywheel) balance power density, energy density, and cost.
Correct answer is: They combine strengths of different storage types to improve overall performance
Q.49 In the context of grid stability, what is 'load shedding'?
Disconnecting non‑essential loads during a shortage
Increasing the grid's capacity
Adding more solar panels
Installing more batteries
Explanation - Load shedding reduces demand by cutting power to some consumers to avoid blackouts.
Correct answer is: Disconnecting non‑essential loads during a shortage
Q.50 Which type of battery has the highest cycle life among commercial options?
Lead‑acid
Lithium‑ion
Flow batteries
Nickel‑metal hydride
Explanation - Flow batteries can endure millions of cycles due to their external electrolyte reservoirs.
Correct answer is: Flow batteries
Q.51 What is the main challenge in integrating renewable energy with battery storage at a large scale?
The randomness of renewable generation
The high cost of communication cables
The lack of demand for electricity
The inability to store hydrogen
Explanation - Renewable output fluctuates, making storage essential to balance supply and demand.
Correct answer is: The randomness of renewable generation
Q.52 Which parameter is most critical in determining battery lifetime?
The color of the casing
The depth of discharge per cycle
The brand name
The temperature of the surrounding air
Explanation - Deeper discharges generally reduce cycle life because of higher stress on cells.
Correct answer is: The depth of discharge per cycle
Q.53 Which communication method is best for low‑power, short‑range devices in a smart grid?
LoRaWAN
Fiber Optic
Satellite
Wi‑Fi Direct
Explanation - LoRaWAN offers low data rates with long range and very low power consumption, ideal for sensors.
Correct answer is: LoRaWAN
Q.54 Which of the following is a key advantage of hydrogen fuel cells for energy storage?
They can be charged in seconds
They provide long‑duration storage with high energy density
They are made of cheap materials
They do not emit any by‑products
Explanation - Hydrogen has a high gravimetric energy density, suitable for seasonal storage.
Correct answer is: They provide long‑duration storage with high energy density
Q.55 What is the purpose of a 'battery management system' (BMS)?
To make the battery look shiny
To monitor and protect the battery by controlling charge and discharge cycles
To physically move the battery around
To measure water consumption
Explanation - BMS ensures safe operation, balances cells, and prolongs battery life.
Correct answer is: To monitor and protect the battery by controlling charge and discharge cycles
Q.56 Which of the following best describes 'Vehicle-to-Grid' (V2G) technology?
Cars driving on the grid
Cars feeding stored energy back to the power network
Cars communicating with traffic lights
Cars that can fly
Explanation - V2G uses the battery capacity of EVs as distributed storage for the grid.
Correct answer is: Cars feeding stored energy back to the power network
Q.57 What is the main difference between 'frequency regulation' and 'voltage regulation' in a smart grid?
Frequency regulation controls the grid's speed, voltage regulation controls its electric potential
Frequency regulation is for water, voltage regulation is for electricity
There is no difference
Frequency regulation is slower than voltage regulation
Explanation - Frequency refers to grid cycles per second; voltage is the electrical potential difference.
Correct answer is: Frequency regulation controls the grid's speed, voltage regulation controls its electric potential
Q.58 Which of these is an example of a 'grid‑connected inverter'?
A solar panel inverter
A battery charger
A transformer
A DC power supply
Explanation - Grid‑connected inverters convert DC from solar panels to AC that can feed into the utility grid.
Correct answer is: A solar panel inverter
Q.59 Which storage technology is known for its quick response but low energy density?
Lithium‑ion batteries
Flywheels
Pumped hydro
Flow batteries
Explanation - Flywheels deliver power very fast, but their stored energy per unit mass is lower.
Correct answer is: Flywheels
Q.60 What is the main challenge with using sodium‑sulfur batteries for grid storage?
They are too light
They require very high operating temperatures
They produce a lot of noise
They cannot be charged
Explanation - Sodium‑sulfur batteries must operate at ~300 °C, necessitating specialized containment.
Correct answer is: They require very high operating temperatures
Q.61 Which of the following best describes 'time‑of‑use pricing'?
Charging electricity at different rates depending on the time of day
Charging electricity only at night
Charging electricity at a flat rate all the time
Charging electricity based on weather conditions
Explanation - Time‑of‑use pricing incentivizes consumers to shift usage to cheaper off‑peak periods.
Correct answer is: Charging electricity at different rates depending on the time of day
Q.62 Which of these is a key metric for evaluating battery performance in a grid application?
Weight
Cycle life
Color
Brand reputation
Explanation - Cycle life indicates how many charge‑discharge cycles a battery can sustain before capacity drops.
Correct answer is: Cycle life
Q.63 What is the main benefit of using 'solid‑state batteries' in electric vehicles?
They are lighter but less safe
They use liquid electrolytes for better performance
They improve safety and potentially increase energy density
They are cheaper than all other batteries
Explanation - Solid‑state electrolytes eliminate flammable liquids, reducing fire risk and allowing higher energy densities.
Correct answer is: They improve safety and potentially increase energy density
Q.64 Which communication technology is typically used for real‑time monitoring of substations?
Fiber optic with IEC 61850
Wi‑Fi
Bluetooth Low Energy
Zigbee
Explanation - Fiber optics provide high bandwidth and low latency, essential for critical substation data.
Correct answer is: Fiber optic with IEC 61850
Q.65 In a battery‑integrated smart grid, what does the term 'state of charge' (SoC) refer to?
The physical size of the battery
The remaining energy capacity as a percentage of total capacity
The number of charge cycles left
The color of the battery casing
Explanation - SoC indicates how much usable energy is left in the battery.
Correct answer is: The remaining energy capacity as a percentage of total capacity
Q.66 Which protocol is commonly used for MQTT messaging in smart grid IoT devices?
MQTT
HTTP
SMTP
FTP
Explanation - MQTT is lightweight and ideal for IoT devices that need low bandwidth, high reliability.
Correct answer is: MQTT
Q.67 What is the main advantage of using flow batteries in power grids?
They are very small
They offer modular scalability and long cycle life
They use solar light
They are the cheapest option
Explanation - Flow batteries can be expanded by adding tanks, and their electrolytes allow many cycles.
Correct answer is: They offer modular scalability and long cycle life
Q.68 What is 'grid stability' primarily concerned with?
Keeping the lights on
Maintaining voltage and frequency within specified limits
Ensuring every house has Wi‑Fi
Reducing the number of power lines
Explanation - Grid stability ensures that voltage and frequency remain within safe operational ranges.
Correct answer is: Maintaining voltage and frequency within specified limits
Q.69 Which technology is used to convert DC energy from batteries into AC for the grid?
Rectifier
Inverter
Transformer
Converter
Explanation - An inverter performs DC‑to‑AC conversion, allowing battery energy to be fed into the AC grid.
Correct answer is: Inverter
Q.70 Which of these is a primary challenge when using batteries as grid energy storage?
High cost of production and disposal
Inability to store renewable energy
Limited geographic availability
Lack of charging stations
Explanation - Batteries can be expensive to manufacture and require careful handling at end‑of‑life.
Correct answer is: High cost of production and disposal
Q.71 What does 'load forecasting' involve in smart grid management?
Predicting future energy consumption patterns
Forecasting weather conditions
Determining the color of lights
Calculating the size of a building's load
Explanation - Accurate load forecasting allows utilities to plan generation and storage accordingly.
Correct answer is: Predicting future energy consumption patterns
Q.72 Which communication protocol ensures end‑to‑end encryption for smart grid data?
TLS
HTTP
FTP
Telnet
Explanation - Transport Layer Security (TLS) encrypts data transmitted between devices and utilities.
Correct answer is: TLS
Q.73 Which of the following is a typical benefit of integrating battery storage with solar PV?
Reducing the need for inverters
Storing excess solar energy for use at night
Increasing the size of solar panels
Eliminating the need for batteries
Explanation - Batteries capture surplus solar output during daylight for later use when panels are inactive.
Correct answer is: Storing excess solar energy for use at night
Q.74 What does the term 'grid‑edge' refer to?
The physical edge of the grid
The point where distributed resources connect to the main grid
The last power line in a city
The edge of a battery cell
Explanation - Grid‑edge devices like storage, PV, and demand response interact directly with the utility network.
Correct answer is: The point where distributed resources connect to the main grid
Q.75 Which parameter is most critical when sizing a battery for a microgrid?
Battery's color
Energy capacity (kWh)
Number of charging ports
Brand name
Explanation - Capacity determines how much energy the battery can store to meet the microgrid's load demands.
Correct answer is: Energy capacity (kWh)
Q.76 In a utility‑scale battery system, what does 'depth of discharge' (DoD) influence?
The battery's color
The battery's cycle life and efficiency
The number of sockets needed
The amount of water used
Explanation - Higher DoD generally reduces cycle life and can lower efficiency due to deeper cycling.
Correct answer is: The battery's cycle life and efficiency
Q.77 What is the primary advantage of using a 'sodium‑sulfur' battery for grid storage?
Low cost of raw materials
High energy density and long cycle life
Fast charging times
Low temperature operation
Explanation - Sodium‑sulfur batteries provide high energy per unit weight and can endure many cycles.
Correct answer is: High energy density and long cycle life
Q.78 Which communication standard is designed specifically for low‑power, wide‑area network applications in energy management?
LoRaWAN
Bluetooth
Wi‑Fi
Ethernet
Explanation - LoRaWAN offers long‑range, low‑power connectivity ideal for sensor networks in grids.
Correct answer is: LoRaWAN
Q.79 What does 'grid‑friendly' mean for a battery system?
The battery can be installed anywhere
The battery can provide services like frequency regulation, voltage support, and demand response
The battery is inexpensive
The battery can be moved easily
Explanation - Grid‑friendly assets adapt to grid needs and provide ancillary services.
Correct answer is: The battery can provide services like frequency regulation, voltage support, and demand response
Q.80 Which of the following is a primary consideration when choosing between lithium‑ion and flow batteries for grid storage?
Color preference
Cost per kWh, scalability, and cycle life
Manufacturer's marketing claims
The shape of the battery pack
Explanation - Decision factors include economics, modularity, and durability under grid conditions.
Correct answer is: Cost per kWh, scalability, and cycle life
Q.81 Which of these is a potential disadvantage of large‑scale battery installations?
They require high operating temperatures
They produce greenhouse gases during operation
They can deplete critical raw materials
They increase grid inertia automatically
Explanation - Large batteries consume metals like lithium and cobalt, raising supply concerns.
Correct answer is: They can deplete critical raw materials
Q.82 What role does 'blockchain' technology play in smart grid energy markets?
It controls the physical grid switches
It provides secure, transparent, decentralized transaction records for energy trading
It cools the grid
It generates electricity
Explanation - Blockchain can enable peer‑to‑peer energy trading with immutable records.
Correct answer is: It provides secure, transparent, decentralized transaction records for energy trading
Q.83 Which of these is a key metric for evaluating the economic viability of a battery storage project?
Return on investment (ROI)
The color of the battery
The number of ports
The brand name
Explanation - ROI measures the financial return relative to the investment cost over the project's life.
Correct answer is: Return on investment (ROI)
Q.84 Which advanced communication protocol ensures secure and reliable data exchange in a smart grid?
IEC 61850 with TLS
Wi‑Fi with HTTP
Bluetooth Low Energy
SMS text messaging
Explanation - IEC 61850 provides data modeling, while TLS adds encryption for secure communications.
Correct answer is: IEC 61850 with TLS
Q.85 What does 'grid inertia' refer to in the context of power systems?
The physical mass of power plants
The ability of rotating machines to resist changes in frequency
The weight of the power lines
The inertia of batteries
Explanation - Inertia helps stabilize frequency by absorbing kinetic energy from generators.
Correct answer is: The ability of rotating machines to resist changes in frequency
Q.86 Which of the following best describes a 'battery‑integrated microgrid'?
A microgrid with a central battery that provides storage and load management
A microgrid that operates without any storage
A microgrid that only uses solar panels
A microgrid that stores water
Explanation - Battery integration enables islanding, backup, and demand response within microgrids.
Correct answer is: A microgrid with a central battery that provides storage and load management
Q.87 Which technology enables high‑frequency power conversion for grid‑connected PV systems?
Power electronic inverters using IGBT or SiC devices
Simple resistors
Mechanical transformers
DC‑to‑DC converters
Explanation - IGBT and SiC devices handle high switching speeds, improving efficiency and grid compliance.
Correct answer is: Power electronic inverters using IGBT or SiC devices
Q.88 Which of these is a primary environmental consideration for large‑scale battery storage?
Battery color waste
Potential for hazardous chemical release and resource depletion
Battery noise levels
Battery manufacturing location
Explanation - Large deployments raise concerns about toxic materials, recycling, and mining impacts.
Correct answer is: Potential for hazardous chemical release and resource depletion
Q.89 What is the purpose of a 'state of health' (SoH) metric in a battery management system?
To indicate how healthy the battery's color is
To estimate the remaining useful life and performance of the battery
To measure how many people own the battery
To calculate the battery's weight
Explanation - SoH quantifies degradation, helping operators decide when to replace or recharge the battery.
Correct answer is: To estimate the remaining useful life and performance of the battery
Q.90 Which of the following is a major advantage of 'hydrogen‑to‑electricity' fuel cells in grid storage?
They produce zero waste products
They allow high‑energy‑density, long‑duration storage with rapid dispatch
They are the cheapest storage technology
They work only during the day
Explanation - Fuel cells can quickly convert stored hydrogen back to electricity, enabling flexible grid support.
Correct answer is: They allow high‑energy‑density, long‑duration storage with rapid dispatch
Q.91 In smart grid communication, what does 'mesh networking' enable?
A single connection point for all devices
Multiple interconnections allowing data to route through various paths for redundancy
Only one device can communicate at a time
Devices cannot communicate outside the mesh
Explanation - Mesh networks provide resilience by allowing multiple data routes.
Correct answer is: Multiple interconnections allowing data to route through various paths for redundancy
Q.92 Which of the following best explains 'power electronics' in the context of grid‑connected storage?
Devices that convert mechanical power to electrical power
Devices that manage the flow of electricity using semiconductor switches for efficient energy conversion and control
Devices that store power in batteries
Devices that only cool down the grid
Explanation - Power electronics control voltage, current, and timing in energy conversion.
Correct answer is: Devices that manage the flow of electricity using semiconductor switches for efficient energy conversion and control