REP Environmental Impacts of Renewables 3 — Questions and Answers
Question 1: A solar farm in the Mojave Desert seeks environmental permits. Which species-specific concern is most likely to require mitigation?
- Monarch butterfly migration corridors
- Desert tortoise habitat displacement (Correct answer)
- Salmon spawning grounds
- Bald eagle nesting sites
Correct answer: Desert tortoise habitat displacement
The desert tortoise is a federally threatened species whose habitat overlaps extensively with utility-scale solar development sites in the Mojave and Sonoran Deserts.
Question 2: What is 'energy payback period' and why is it relevant to environmental assessment of renewables?
- The time for a project to become financially profitable
- The time a renewable system operates before needing replacement
- The time needed for a renewable system to generate the energy used in its production (Correct answer)
- The period during which tax incentives apply to a renewable project
Correct answer: The time needed for a renewable system to generate the energy used in its production
Energy payback period measures environmental efficiency — a shorter payback means the system spends more of its life genuinely offsetting fossil fuel emissions rather than repaying its manufacturing debt.
Question 3: Which wind energy development scenario raises the greatest concern for bat mortality?
- Offshore wind farms in the North Atlantic
- Mountain ridge turbines near forested areas during migration season (Correct answer)
- Urban rooftop micro-turbines
- Turbines sited in open agricultural plains
Correct answer: Mountain ridge turbines near forested areas during migration season
Forested ridgelines concentrate migrating bats following terrain, and turbine blades create barotrauma (internal injuries from pressure change) that kills bats even without direct contact.
Question 4: In lifecycle analysis (LCA) of renewable energy, what does the term 'system boundary' define?
- The geographic area of the project site
- The scope of processes and inputs included in the environmental accounting (Correct answer)
- The capacity limit of the renewable energy system
- The fence line separating the facility from public land
Correct answer: The scope of processes and inputs included in the environmental accounting
System boundary determines which upstream (raw material extraction) and downstream (end-of-life) stages are counted in the LCA, directly affecting the completeness and comparability of results.
Question 5: Thin-film solar panels using cadmium telluride (CdTe) raise environmental concerns primarily because cadmium is:
- Radioactive with a short half-life
- A heavy metal that is toxic and persists in the environment (Correct answer)
- Flammable when exposed to sunlight
- Scarce and must be imported from conflict zones
Correct answer: A heavy metal that is toxic and persists in the environment
Cadmium is a highly toxic heavy metal that bioaccumulates in ecosystems and can leach from panels in landfills if not properly managed at end-of-life.
Question 6: What environmental risk is specifically associated with enhanced geothermal systems (EGS)?
- Large greenhouse gas releases from deep rock formations
- Induced seismicity from hydraulic fracturing of rock (Correct answer)
- Heavy metal contamination of solar panel manufacturing
- Thermal pollution of nearby rivers and lakes
Correct answer: Induced seismicity from hydraulic fracturing of rock
EGS injects water at high pressure to fracture deep rock, a process that can trigger minor to moderate earthquakes — a risk that has caused project suspensions in Switzerland and South Korea.
Question 7: Which federal law most directly governs the environmental review process for large renewable energy projects on public lands in the US?
- The Clean Air Act (CAA)
- The National Environmental Policy Act (NEPA) (Correct answer)
- The Renewable Fuel Standard (RFS)
- The Energy Policy Act of 2005
Correct answer: The National Environmental Policy Act (NEPA)
NEPA requires federal agencies to assess environmental impacts through Environmental Assessments (EAs) or Environmental Impact Statements (EISs) before approving major projects on federal land.
REP Environmental Impacts of Renewables 3
A solar farm in the Mojave Desert seeks environmental permits.
Which species-specific concern is most likely to require mitigation?