REP Environmental Impacts of Renewables 4 — Questions and Answers
Question 1: How does the albedo effect relate to utility-scale solar farm deployment?
- Solar panels reflect sunlight back into space, cooling the atmosphere globally
- Replacing reflective desert sand or crops with dark solar panels can locally raise temperatures (Correct answer)
- Solar panels increase albedo by converting light to electricity
- Albedo is irrelevant to solar energy and only applies to arctic regions
Correct answer: Replacing reflective desert sand or crops with dark solar panels can locally raise temperatures
Dark solar panels absorb more sunlight than the light-colored soils or vegetation they replace, potentially creating a local warming microclimate known as a 'heat island' effect.
Question 2: What is the main environmental advantage of run-of-river hydropower compared to reservoir-based hydropower?
- Higher energy output per unit of water used
- Significantly less disruption to river flow and ecosystems (Correct answer)
- Zero construction impact on riverbanks
- Elimination of fish passage concerns
Correct answer: Significantly less disruption to river flow and ecosystems
Run-of-river systems divert only a portion of river flow without creating large reservoirs, preserving more natural flow regimes, sediment transport, and aquatic habitat.
Question 3: Which environmental metric best captures the total climate benefit of replacing a coal plant with a wind farm over 25 years?
- Peak power capacity (MW)
- Cumulative CO2-equivalent emissions avoided (Correct answer)
- Annual energy output (MWh/year)
- Capacity factor (%)
Correct answer: Cumulative CO2-equivalent emissions avoided
Cumulative avoided CO2-equivalent emissions aggregate all greenhouse gases over the project lifetime, capturing the actual climate benefit compared to the displaced fossil generation.
Question 4: What is 'shadow flicker' and which environmental domain does it affect?
- Light reflection from solar panels affecting soil temperature
- Alternating shadows cast by rotating turbine blades affecting nearby human health and comfort (Correct answer)
- Flickering of inverter output affecting power quality
- Shadow zones created by offshore platforms affecting marine photosynthesis
Correct answer: Alternating shadows cast by rotating turbine blades affecting nearby human health and comfort
Shadow flicker occurs when rotating blades periodically block sunlight, creating a strobe-like effect that can cause discomfort, headaches, or seizure risk in photosensitive individuals living near turbines.
Question 5: Which type of solar installation has the lowest overall land use impact per unit of energy produced?
- Utility-scale ground-mounted systems in remote deserts
- Building-integrated photovoltaics (BIPV) on existing structures (Correct answer)
- Concentrated solar power (CSP) with thermal storage
- Floating solar (floatovoltaics) on reservoirs
Correct answer: Building-integrated photovoltaics (BIPV) on existing structures
BIPV integrates panels into existing building envelopes, consuming no additional land since the building footprint is already developed and the energy is generated where it is used.
Question 6: What environmental concern has led some states to require decommissioning bonds for wind and solar projects?
- Risk of groundwater contamination during operation
- Ensuring funds exist for proper removal and site restoration when projects end (Correct answer)
- Covering costs of bird and bat mortality monitoring programs
- Liability for electromagnetic interference with neighboring properties
Correct answer: Ensuring funds exist for proper removal and site restoration when projects end
Decommissioning bonds ensure that developers cannot abandon sites at end-of-life, leaving landowners and communities responsible for the cost of removing turbines, panels, and foundations.
Question 7: Biomass energy is sometimes classified as 'carbon neutral' — what is the primary challenge to this classification?
- Biomass power plants emit more NOx than coal plants
- The carbon released at combustion may not be reabsorbed for decades, creating a 'carbon debt' (Correct answer)
- Biomass feedstocks contain radioactive isotopes that complicate accounting
- Biomass combustion produces methane rather than CO2
Correct answer: The carbon released at combustion may not be reabsorbed for decades, creating a 'carbon debt'
Burning biomass releases CO2 immediately, but the replacement trees take 20–100 years to regrow and reabsorb that carbon, meaning short-term atmospheric CO2 increases even if the system is ultimately carbon neutral.
REP Environmental Impacts of Renewables 4
How does the albedo effect relate to utility-scale solar farm deployment?