Environmental Science Renewable Energy Systems

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 compresses a refrigerant that drives a heat engine connected to a generator

Answer

Wind pressure pushes pistons in a reciprocating engine connected to an alternator

Answer

Wind forces air into a compressed tank; the compressed air then powers a turbine

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

The high upfront capital cost that makes projects financially uncertain

Answer

The environmental impact of manufacturing solar panels and wind turbine blades

Answer

The limited number of suitable locations for utility-scale renewable installations

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

The fuel cost per kilowatt-hour over a power plant's operating life

Answer

The upfront capital cost of a renewable project divided by its rated capacity

Answer

The annual revenue required to make a power plant financially viable

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

Temperature differences between deep and surface ocean water

Answer

The kinetic energy of ocean waves generated by wind at the surface

Answer

Differences in salinity between freshwater river mouths and seawater

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

Emission of carbon dioxide from turbine combustion gases

Answer

Radioactive contamination of downstream water supplies

Answer

Depletion of groundwater aquifers that feed the river system

Question 6

Second-generation biofuels differ from first-generation biofuels in that they:

Accepted Answer

Are derived from non-food feedstocks (cellulosic biomass, agricultural residues, algae) that don't compete with food production

Answer

Are produced from food crops like corn and sugarcane rather than waste biomass

Answer

Use the same fermentation processes as first-generation but with more efficient yeast strains

Answer

Are liquid fuels burned in conventional engines without any engine modification