Hydroelectric and Geothermal Power Plant Review

A comprehensive practice exam based on Sets 22, 23, and 24 covering hydroelectric and geothermal power plant concepts, components, and theoretical laws.

Which factor defines the specific speed of turbines?

Speed of geometrically similar turbine under unit head

Which turbine has fixed runner blades and adjustable guide vanes?

Francis turbine

Which factor reduces turbine efficiency at part load?

Flow separation and cavitation

Which factor defines hydro plant firm power?

Minimum guaranteed power output

Which type of load can pumped storage plants handle efficiently?

Peak load

Which term defines the energy per unit volume of water?

Pressure head

Which factor defines unit discharge?

$$\text{Flow per unit head}^{1/2}$$

Which term defines head loss due to sudden closure of a penstock valve?

Water hammer

Which parameter defines the unit power of a turbine?

$$\text{Power per unit head}^{3/2}$$

Which efficiency relates the ratio of actual energy generated to the maximum possible energy?

Plant utilization factor

Which dam type is recommended for a soft foundation?

Earthen dam

Which type of dam uses upstream arch action to resist water pressure?

Arch dam

What is the primary energy source of a geothermal power plant?

Heat from Earth's interior

Which fluid is expanded in a binary cycle geothermal plant?

Secondary working fluid (e.g., isobutane, pentane)

What is the function of a separator in geothermal plants?

To separate steam from hot water

What is the role of reinjection wells in geothermal systems?

To dispose of spent geothermal fluids back underground

Which type of geothermal reservoir contains steam only?

Vapor-dominated reservoir

Which law governs heat conduction in rocks?

Fourier's law

Which gas besides $H_2S$ is common in geothermal steam?

$$CO_2$$

Which region in the Philippines is a major geothermal producer?

Leyte and Bicol

Which geothermal cycle uses an ammonia-water mixture?

Kalina cycle

Which factor defines geothermal gradient?

Rate of temperature increase with depth (expressed in $^\circ C/km$)

Which process occurs in a reinjection well?

Spent geothermal fluid is returned underground

Which component in geothermal plants prevents turbine overspeed?

Emergency trip valve (ETV)

Which law governs geothermal reservoir pressure decline and fluid flow?

Darcy's law

Which geothermal field is the largest dry steam field?

The Geysers (USA)

Which plant capacity factor is typical for geothermal power plants?

$$80\text{--}95\,$$

Which efficiency measures the ratio of actual work done to isentropic work in a turbine?

Isentropic efficiency

Which device is used to measure headwater and tailwater levels accurately?

Staff gauge and level recorder

Which standard commonly guides the testing and performance evaluation of hydro-generators?

IEC 60034 series

Which factor governs the selection between Pelton, Francis, and Kaplan turbines?

Net head and discharge

Which type of hydro plant is used for isolated small communities?

Micro-hydro plant ($<100\,kW$)

Which aspect of geothermal power production requires artificial stimulation like fracturing?

Enhanced Geothermal System (EGS) or Hot Dry Rock (HDR)

Which environmental concern is significant in geothermal plants due to odor and toxicity?

Hydrogen sulfide ($H_2S$) emissions

What is the purpose of cement in geothermal well completion?

To prevent casing collapse

Which turbine efficiency is affected by leakage through labyrinth seals or around guide vanes?

Volumetric efficiency

Which parameter governs the selection of binary cycle working fluids?

Boiling point and heat transfer properties

Which factor limits the sustainability of a geothermal reservoir?

Overproduction and inadequate reinjection

Which device extracts non-condensable gases from the condenser?

Steam ejectors or vacuum pumps

Which strategy ensures the long-term sustainability of geothermal reservoirs?

Balanced production and reinjection strategy