CEA Renewable Energy Technologies 2 — Questions and Answers
Question 1: What is the typical capacity factor range for utility-scale onshore wind farms in the US?
- 10–20%
- 25–45% (Correct answer)
- 55–70%
- 75–90%
Correct answer: 25–45%
Onshore wind farms in the US typically achieve capacity factors of 25–45%, depending on site wind resources.
Question 2: Which component in a concentrating solar power (CSP) plant stores thermal energy for use after sunset?
- Lithium-ion battery bank
- Molten salt storage tank (Correct answer)
- Compressed air reservoir
- Flywheel energy storage
Correct answer: Molten salt storage tank
Molten salt thermal energy storage allows CSP plants to generate electricity hours after the sun sets.
Question 3: In a photovoltaic system, what is the primary function of the maximum power point tracker (MPPT)?
- Prevent reverse current flow at night
- Regulate battery charging cycles
- Optimize panel output as conditions change (Correct answer)
- Convert DC to AC power
Correct answer: Optimize panel output as conditions change
An MPPT continuously adjusts the electrical operating point to extract maximum power from PV panels under varying irradiance and temperature.
Question 4: Which offshore wind foundation type is most suitable for water depths exceeding 60 meters?
- Monopile
- Gravity base
- Jacket structure
- Floating semi-submersible (Correct answer)
Correct answer: Floating semi-submersible
Floating semi-submersible platforms are used in deep water (>60 m) where fixed-bottom foundations become uneconomical.
Question 5: What does the term 'perovskite' refer to in the context of next-generation solar cells?
- A crystalline silicon purification process
- A light-absorbing material with ABX3 crystal structure (Correct answer)
- A type of anti-reflective coating
- A bifacial panel architecture
Correct answer: A light-absorbing material with ABX3 crystal structure
Perovskite solar cells use a material with ABX3 crystal structure that efficiently absorbs sunlight and has shown rapid efficiency gains.
Question 6: What is the Betz limit in wind energy?
- The maximum voltage a wind turbine can produce
- The theoretical maximum efficiency of 59.3% for extracting kinetic energy from wind (Correct answer)
- The minimum wind speed required for turbine operation
- The structural load limit for turbine blades
Correct answer: The theoretical maximum efficiency of 59.3% for extracting kinetic energy from wind
The Betz limit, approximately 59.3%, is the theoretical maximum fraction of kinetic energy a wind turbine can extract from free-flowing air.
Question 7: Run-of-river hydropower differs from reservoir hydropower primarily because it:
- Uses tidal fluctuations rather than river flow
- Generates electricity only from rainfall events
- Operates without a large water storage reservoir (Correct answer)
- Requires a minimum head of 100 meters
Correct answer: Operates without a large water storage reservoir
Run-of-river hydropower diverts a portion of river flow through turbines with minimal or no reservoir storage, resulting in lower environmental impact.
CEA Renewable Energy Technologies 2
What is the typical capacity factor range for utility-scale onshore wind farms in the US?