REP Geothermal and Hydropower 2

Question 1

What is the primary environmental concern associated with geothermal power plants using open-loop hydrothermal systems?

Accepted Answer

Emission of hydrogen sulfide (H₂S) gas

Answer

Excessive water vapor condensation

Answer

Thermal runaway in turbines

Answer

Increased seismic activity from steam injection

Question 2

A run-of-river hydropower project generates electricity without a large reservoir. What is the main trade-off compared to storage hydropower?

Accepted Answer

Less predictable and dispatchable power output

Answer

Higher capital cost per MW installed

Answer

Greater ecological disruption to fish habitat

Answer

Lower turbine efficiency at rated flow

Question 3

In binary-cycle geothermal plants, what role does the working fluid (e.g., isobutane or isopentane) play?

Accepted Answer

It absorbs heat from geothermal brine and vaporizes to drive a turbine

Answer

It is injected into the geothermal reservoir to increase pressure

Answer

It cools the generator windings to prevent overheating

Answer

It reacts chemically with minerals in the brine to purify the fluid

Question 4

The penstock in a hydropower facility performs which function?

Accepted Answer

Conveys pressurized water from the forebay or reservoir to the turbine

Answer

Filters suspended sediment before water enters the turbine

Answer

Regulates downstream river flow for environmental compliance

Answer

Converts turbine mechanical energy to electrical energy

Question 5

Which geothermal resource type is characterized by temperatures above 150°C and is best suited for direct electricity generation?

Accepted Answer

High-enthalpy hydrothermal reservoirs

Answer

Ground-source heat pump fields

Answer

Low-temperature sedimentary aquifers

Answer

Shallow soil thermal exchange zones

Question 6

A pumped-storage hydropower facility consumes electricity during off-peak hours. What is the primary purpose of this operation?

Accepted Answer

To store energy by pumping water to an upper reservoir for later generation

Answer

To irrigate agricultural land using surplus reservoir water

Answer

To maintain minimum ecological flow downstream during dry periods

Answer

To test turbine efficiency at various hydraulic head conditions

Question 7

What distinguishes Enhanced Geothermal Systems (EGS) from conventional geothermal power production?

Accepted Answer

EGS creates or enhances permeability in hot dry rock through hydraulic stimulation

Answer

EGS plants use only solar thermal energy to supplement geothermal heat

Answer

EGS extracts energy from shallow soil temperature gradients below 30°C

Answer

EGS relies exclusively on naturally occurring steam vents at the surface