Environmental Science Renewable Energy Systems 1

Question 1

Which of the following best describes how a wind turbine generates electricity?

Accepted Answer

Moving air turns rotor blades, spinning a shaft connected to a generator through a gearbox or direct drive

Answer

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.

Question 2

The intermittency problem with solar and wind power refers to:

Accepted Answer

The fact that output varies with weather and time of day, creating challenges for grid balancing

Answer

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.

Question 3

Levelized Cost of Energy (LCOE) is calculated as:

Accepted Answer

The total lifecycle cost of building and operating a power plant divided by the total energy it produces

Answer

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.

Question 4

Tidal energy harvests power from:

Accepted Answer

The predictable rise and fall of sea level caused by gravitational forces of the Moon and Sun

Answer

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).

Question 5

The primary environmental concern associated with large hydroelectric dams is:

Accepted Answer

Disruption of river ecosystems, blocking fish migration, and flooding of upstream habitats and communities

Answer

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.

Environmental Science Practice Test

Environmental Science Practice Test

Environmental Science Renewable Energy Systems 1