Levelized cost of energy divides lifetime cost by what?
A Installed capacity only
B Fuel mass
C Lifetime energy output
D Peak demand
Answer: C. Lifetime energy output. LCOE expresses discounted lifetime cost per unit of energy generated.
Intermittency describes generation that varies with what?
A Grid voltage only
B Panel color
C Turbine mass
D Resource availability
Answer: D. Resource availability. Solar and wind output vary as weather and resource conditions change.
Grid balancing matches generation with what?
A Electricity demand
B Fuel quality
C Turbine height
D Battery chemistry only
Answer: A. Electricity demand. Power systems continually balance generation and consumption.
A lithium-ion battery stores energy through what process?
A Wind rotation
B Water elevation
C Steam compression
D Electrochemical reactions
Answer: D. Electrochemical reactions. Lithium-ion cells store and release energy through reversible electrochemical reactions.
A flow battery stores energy in what?
A Liquid electrolytes
B Rotor blades
C Compressed air only
D Hot rocks only
Answer: A. Liquid electrolytes. Flow batteries store active materials in liquid electrolyte tanks.
Pumped hydro storage converts electrical energy into what stored form?
A Chemical fuel
B Gravitational potential
C Solar radiation
D Wind momentum
Answer: B. Gravitational potential. Pumping water uphill stores gravitational potential energy.
Thermal storage can store energy as sensible heat or what?
A Latent heat
B Gear torque
C Wind pressure
D Electrical resistance only
Answer: A. Latent heat. Thermal storage uses temperature change or phase change to store heat.
Demand response changes electricity use in response to what?
A Solar cell color
B Turbine blade count
C Grid conditions or prices
D Fuel octane
Answer: C. Grid conditions or prices. Demand response shifts or reduces load to support grid operation.
A smart grid uses digital communication and what?
A Automated control
B Manual-only meters
C No sensors
D Fixed generation only
Answer: A. Automated control. Smart grids use sensing, communication and control to improve system operation.
Frequency regulation helps maintain grid what?
A Panel orientation
B Frequency stability
C Water head
D Wind speed
Answer: B. Frequency stability. Frequency services balance real-time generation and load.
Renewable curtailment means reducing available generation because of what?
A Low equipment quality only
B No sunlight ever
C System limits or surplus
D Generator failure always
Answer: C. System limits or surplus. Curtailment occurs when available output is intentionally reduced due to grid or market constraints.
Transmission upgrades can reduce renewable what?
A Solar irradiance
B Congestion
C Wind resource
D Battery capacity
Answer: B. Congestion. Grid transmission can move renewable energy from resource areas to load centers.
Grid-support inverters can provide voltage and what support?
A Frequency
B Water head
C Blade pitch
D Fuel pressure
Answer: A. Frequency. Advanced inverters can support voltage, frequency and grid stability.
A grid-forming inverter can establish what reference?
A Voltage and frequency
B Solar irradiance
C Battery chemistry
D Wind direction
Answer: A. Voltage and frequency. Grid-forming controls establish a voltage waveform and frequency reference.
Lifecycle assessment evaluates impacts across what stages?
A Only factory gate
B Only operation
C Product life cycle
D Only disposal
Answer: C. Product life cycle. LCA considers resource extraction, manufacturing, use and end-of-life impacts.
Energy payback time compares embodied energy with what?
A Energy generated
B Installed cost
C Peak power
D Battery voltage
Answer: A. Energy generated. Energy payback time is when cumulative energy output equals energy invested.
PV module recycling can recover glass, metals and what?
A Wind resource
B Hydrogen fuel
C Geothermal steam
D Semiconductor materials
Answer: D. Semiconductor materials. Recycling can recover glass, aluminum, copper and semiconductor materials.
Wind turbine blade recycling is challenging due to what?
A Pure steel construction
B Composite materials
C No resin
D Liquid fuel content
Answer: B. Composite materials. Composite blades combine fibers and resins that are difficult to separate.
Distributed generation is located near what?
A Only central plants
B Fuel mines only
C Transmission towers only
D Electricity consumers
Answer: D. Electricity consumers. Distributed resources are placed near loads or within distribution networks.
A microgrid can operate connected to or separated from what?
A Fuel cell only
B Main grid
C Battery pack only
D Wind turbine tower
Answer: B. Main grid. Microgrids can connect to the utility or island when needed.
Net-zero energy balances energy use with what over a period?
A Peak demand only
B Fuel mass
C Energy supplied or generated
D Grid frequency
Answer: C. Energy supplied or generated. Net-zero energy aims to match annual consumption with energy supplied or produced.
Carbon intensity measures emissions per unit what?
A Installed capacity
B Panel area
C Energy output
D Turbine speed
Answer: C. Energy output. Carbon intensity is greenhouse-gas emissions divided by energy generated or consumed.
Renewable portfolio diversity can improve what?
A Panel temperature
B Supply reliability
C Turbine noise
D Battery mass
Answer: B. Supply reliability. A mix of resources can reduce dependence on one variable source.
Battery round-trip efficiency is discharged energy divided by what?
A Battery mass
B Peak power
C Cell voltage
D Charging energy
Answer: D. Charging energy. Round-trip efficiency compares energy returned with energy used to charge.
A renewable microgrid may combine PV with batteries and what?
A Only coal boilers
B No inverter
C A single transmission line
D Local loads and controls
Answer: D. Local loads and controls. Microgrids coordinate local generation, storage, loads and controls.