Renewable Energy Systems Flashcards
6 cards from real Environmental Science practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Renewable Energy Systems flashcards as text
Which of the following best describes how a wind turbine generates electricity?
Answer: Moving air turns rotor blades, spinning a shaft connected to a generator through a gearbox or direct drive
Wind turns aerodynamic rotor blades, which rotate a low-speed shaft; a gearbox (or direct-drive system) increases rotational speed to drive a generator producing electricity.
The intermittency problem with solar and wind power refers to:
Answer: The fact that output varies with weather and time of day, creating challenges for grid balancing
Unlike dispatchable power plants (coal, gas, nuclear) that generate on demand, solar and wind output fluctuates with conditions, requiring storage, backup generation, or grid flexibility to maintain reliable supply.
Levelized Cost of Energy (LCOE) is calculated as:
Answer: The total lifecycle cost of building and operating a power plant divided by the total energy it produces
LCOE = (total lifetime costs including capital, O&M, fuel, decommissioning) divided by (total lifetime energy output), expressed as dollars per MWh, enabling comparison across different technologies.
Tidal energy harvests power from:
Answer: The predictable rise and fall of sea level caused by gravitational forces of the Moon and Sun
Tidal power captures energy from the twice-daily tidal cycles driven by lunar and solar gravitational forces - via tidal barrages (potential energy of tidal range) or tidal stream generators (kinetic energy of tidal currents).
The primary environmental concern associated with large hydroelectric dams is:
Answer: Disruption of river ecosystems, blocking fish migration, and flooding of upstream habitats and communities
Large dams block fish passage (salmon, shad, sturgeon), flood unique terrestrial and riparian ecosystems, displace communities, alter downstream sediment and flow regimes, and can emit methane from decomposing organic matter in reservoirs.
Second-generation biofuels differ from first-generation biofuels in that they:
Answer: Are derived from non-food feedstocks (cellulosic biomass, agricultural residues, algae) that don't compete with food production
Second-generation (advanced) biofuels use lignocellulosic feedstocks (switchgrass, wood chips, corn stover, municipal solid waste) or algae, avoiding the food vs. fuel conflict of corn ethanol and sugarcane ethanol.