Hydroelectricity / Hydropower tubrines

Question 1

What is the most common type of turbine used for medium to large scale hydroelectric plants?

Answer 1

Francis

Francis turbines are utilized for heads of 2 to 200 meters and feature radial flow.

Question 2

What are the characteristics of a Francis turbine?

Answer 2

• Medium to large scale plants
• 2 - 200m head (medium head)
• Radial flow
• Response to demand changes by adjusting the angle of the guide vanes
• Fully submerged

Francis turbines adjust to demand changes effectively.

Question 3

What type of turbine is used for high head hydro applications?

Answer 3

Pelton

Pelton turbines are designed for high head applications.

Question 4

What is a dam in hydroelectricity?

how does it operate.

Answer 4

• River water stored in reservoir
• Stored water flows through penstock
• Spins turbine/generator

Dams allow for high capacity energy generation but come with high costs and environmental impacts.

Question 5

What is pumped storage in hydroelectric systems?

Answer 5

• During low demand, energy generated elsewhere is stored by pumping water from low to high
• During high demand, energy is released from high to low, generating electricity

Pumped storage acts as a giant battery for grid balancing.

Question 6

What is a disadvantage of pumped storage?

Answer 6

Lose energy during pumping

Pumping water from low to high elevation results in energy loss.

Question 7

What is required for effective pumped storage?

Answer 7

Large height difference

A significant elevation change is necessary for efficient pumped storage operation.

Question 8

What defines a run-of-river hydroelectric system?

Answer 8

• Portion of river flow channeled off to the side
• River flows through penstock
• Generates power through turbine
• Flow returns to main flow

Run-of-river systems do not involve water storage.

Question 9

What are the limitations of a run-of-river hydroelectric system?

Answer 9

• No storage
• Limited output during low flow

This type of system is also considered eco-friendly.

Question 10

What types of turbines are categorized as high head hydro turbines?

Answer 10

• Pelton
• Turgo

High head turbines are designed for environments with significant elevation.

Question 11

Fill in the blank: The _______ turbine is designed for medium head applications.

Answer 11

Francis

Question 12

True or False: A run-of-river system can store water.

Answer 12

False

Run-of-river systems rely on the natural flow of the river without storage.

Question 13

what are some key components of hydropower systems

Answer 13

dam - captures and stores water
reservoir - stores water for controlled release
penstock - channels water to turbines
turbines - converts kinetic energy to mechanical energy
generator - converts mechanical energy to electrical energy

Question 14

determine the power delivered per month by a hydroelectric system that has Q=20 kg/s & H = 5M.
EFFICIENCY =80%.

Answer 14

Power (P) = pgHQn
P x hr x days

ans=564 MW

Question 15

hydro plant with following specifications:
Power generation P = 400 kW
head H = 150 m
efficiency n = 70%

a) calculate flow rate.
b) calculate nozzle diameter.

Answer 15

Q = p / pgHn
a) ans = 0.39 m^3/s

A = pi x r^2
Q = V(jet) x A(jet)
V(jet) = sqrt(2ngH)

b) ans = 0.107m

Question 16

what turbine is used for low head applications

Answer 16

kaplan - under 20m

Question 17

steps to calculate: volume required to power building, given H, P & n

Answer 17

1. E = P * t
   // P = E / t
2. E = pgHVn
   // V = E / pgHVn