REP Environmental Impacts of Renewables 2 — Questions and Answers
Question 1: Which environmental concern is most commonly associated with large-scale hydropower dams?
- Greenhouse gas emissions from turbines
- Disruption of fish migration and aquatic ecosystems (Correct answer)
- Soil contamination from lubricants
- Increased UV radiation downstream
Correct answer: Disruption of fish migration and aquatic ecosystems
Large dams block fish migration routes and alter downstream flow, temperature, and sediment transport, significantly disrupting aquatic ecosystems.
Question 2: What is 'land use intensity' in the context of comparing renewable energy sources?
- The amount of toxic waste produced per megawatt-hour
- The area of land required to generate a unit of electricity (Correct answer)
- The depth of soil disturbance during installation
- The number of wildlife species displaced per project
Correct answer: The area of land required to generate a unit of electricity
Land use intensity measures how many acres or hectares are needed per unit of energy output, allowing comparison of the footprint of different energy technologies.
Question 3: Which byproduct of manufacturing crystalline silicon photovoltaic cells poses the greatest toxicity concern?
- Silicon dioxide dust
- Trichlorosilane (TCS) (Correct answer)
- Aluminum frames
- Tempered glass shards
Correct answer: Trichlorosilane (TCS)
Trichlorosilane is a highly flammable and toxic chemical used in the Siemens process for purifying silicon, requiring careful handling and disposal.
Question 4: Wind farms are often sited offshore to reduce which onshore environmental impact?
- Saltwater corrosion of turbine components
- Visual impact and noise disturbance to human communities (Correct answer)
- Reduced wind speeds over land
- Higher bird collision rates onshore
Correct answer: Visual impact and noise disturbance to human communities
Offshore siting removes turbines from view and reduces noise exposure for nearby residents, addressing two of the most common community objections to wind development.
Question 5: What environmental benefit does geothermal energy have compared to fossil fuel power plants of equivalent capacity?
- It produces zero emissions of any kind
- It has dramatically lower CO2 emissions per kilowatt-hour (Correct answer)
- It requires no water for cooling
- It produces no solid waste
Correct answer: It has dramatically lower CO2 emissions per kilowatt-hour
Geothermal plants emit far less CO2 per kWh than fossil fuel plants, though binary-cycle plants approach near-zero emissions while flash and dry steam plants release some geothermal gases.
Question 6: Which lifecycle phase of solar PV panels is responsible for the majority of their carbon footprint?
- Installation and grid connection
- Manufacturing and materials processing (Correct answer)
- Operation and maintenance
- Decommissioning and recycling
Correct answer: Manufacturing and materials processing
The energy-intensive processes of purifying silicon, manufacturing cells, and producing frames account for most of a PV panel's lifetime greenhouse gas emissions.
Question 7: What is the primary concern regarding rare earth elements (REEs) used in permanent magnet wind turbines?
- REEs cause direct air pollution during turbine operation
- Mining REEs creates significant environmental damage and waste (Correct answer)
- REEs make turbines incompatible with grid interconnection
- REEs are flammable and increase fire risk
Correct answer: Mining REEs creates significant environmental damage and waste
Extraction of rare earth elements like neodymium produces radioactive tailings and causes substantial land and water contamination, primarily in the countries where they are mined.
REP Environmental Impacts of Renewables 2
Which environmental concern is most commonly associated with large-scale hydropower dams?