Renewable Energy Technologies Flashcards
7 cards from real CEA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Renewable Energy Technologies flashcards as text
Which metric best describes the total electricity generated by a solar PV system over its lifetime relative to the energy used to manufacture and install it?
Answer: Energy payback ratio (EPR)
The energy payback ratio (EPR) compares lifetime energy output to embodied energy, indicating net energy gain from a PV system.
In a wind turbine drivetrain, a gearbox-free direct-drive design eliminates the gearbox by using:
Answer: A low-speed permanent magnet generator with many pole pairs
Direct-drive turbines use low-speed permanent magnet generators with many pole pairs to match rotor RPM without mechanical gearing.
What is the primary purpose of a power purchase agreement (PPA) in renewable energy project finance?
Answer: Provide a long-term contract guaranteeing electricity sale price and volume
A PPA is a long-term contract between an energy producer and buyer that locks in the price and volume of electricity sold, reducing revenue risk.
What differentiates a parabolic trough CSP system from a power tower (central receiver) CSP system?
Answer: Parabolic troughs focus sunlight onto a linear receiver; power towers concentrate it onto a central point
Parabolic troughs use curved mirrors to focus sunlight onto a linear tube receiver, while power towers use hundreds of heliostats to focus on a central point at higher temperatures.
Which geothermal power plant type is best suited for lower-temperature hydrothermal resources (below 150°C)?
Answer: Binary cycle plant
Binary cycle plants use a secondary working fluid with a lower boiling point, enabling power generation from lower-temperature geothermal resources.
What is 'curtailment' in the context of renewable energy grid integration?
Answer: Forced reduction of output below available generation capacity
Curtailment occurs when grid operators force renewable generators to reduce output below what they could produce, typically due to transmission constraints or excess supply.
In tidal stream energy systems, power output is proportional to water velocity raised to which power?
Answer: Third power (cubed)
Like wind turbines, tidal stream turbines extract kinetic energy from moving fluid, and power is proportional to the cube of fluid velocity.