Climate Change Renewable Energy Technologies 3 — Questions and Answers
Question 1: What is 'grid parity' in the context of renewable energy?
- When renewable and fossil fuel plants have the same physical size
- When renewable energy costs equal or fall below conventional electricity prices (Correct answer)
- When the electric grid uses exactly 50% renewable sources
- When different renewable sources produce equal amounts of power
Correct answer: When renewable energy costs equal or fall below conventional electricity prices
Grid parity occurs when a renewable energy source can generate electricity at a cost equal to or less than buying power from the conventional grid, making it economically competitive without subsidies.
Question 2: Which component in a wind turbine converts mechanical rotation into electricity?
- The nacelle
- The rotor blade
- The generator (Correct answer)
- The transformer
Correct answer: The generator
The generator inside the nacelle converts the mechanical rotational energy from the spinning blades into electrical energy through electromagnetic induction.
Question 3: Tidal energy technologies harness power from:
- Ocean surface waves driven by wind
- The gravitational pull of the moon causing water level changes (Correct answer)
- Temperature differences between ocean surface and deep water
- Salinity differences between river and ocean water
Correct answer: The gravitational pull of the moon causing water level changes
Tidal energy exploits the rise and fall of sea levels caused primarily by the gravitational attraction of the moon (and to a lesser extent the sun) on Earth's oceans.
Question 4: What is the 'duck curve' problem in solar energy grid management?
- The bending of solar panels under wind load
- A mismatch between solar generation peaks and evening electricity demand peaks (Correct answer)
- The shape of a solar panel efficiency curve over its lifetime
- Increased power line losses shaped like a duck's neck
Correct answer: A mismatch between solar generation peaks and evening electricity demand peaks
The duck curve describes the grid challenge where midday solar overproduction followed by a steep evening demand ramp creates a curve resembling a duck when graphed over 24 hours.
Question 5: Run-of-river hydropower differs from reservoir-based hydropower because it:
- Generates electricity only during rain events
- Uses river flow without significant water storage, reducing ecological disruption (Correct answer)
- Can only be built on large rivers
- Produces no usable electricity during dry seasons
Correct answer: Uses river flow without significant water storage, reducing ecological disruption
Run-of-river projects divert part of a river's natural flow through turbines without large reservoir storage, causing less flooding of land and lower disruption to river ecosystems.
Question 6: What percentage of the world's electricity could theoretically be supplied by rooftop solar panels on existing buildings, according to international energy studies?
- Less than 5%
- Around 25%
- More than 50% (Correct answer)
- Exactly 100%
Correct answer: More than 50%
Studies by organizations including the International Energy Agency suggest existing rooftops worldwide could host enough solar capacity to supply over 50% of global electricity demand.
Question 7: Biomass energy is considered carbon-neutral under which condition?
- When burned at very high temperatures
- When the carbon released is reabsorbed by replanted vegetation over its growth cycle (Correct answer)
- When combined with natural gas in power plants
- When the biomass comes from agricultural waste only
Correct answer: When the carbon released is reabsorbed by replanted vegetation over its growth cycle
Biomass is considered carbon-neutral only when new plant growth absorbs the same amount of CO₂ released during combustion, closing the carbon cycle over a relevant timeframe.
Climate Change Renewable Energy Technologies 3
What is 'grid parity' in the context of renewable energy?