Hydropower

Question 1

How is renewable energy defined?

Answer 1

Energy derived from natural processes that are replenished constantly.

Question 2

What sources are included in renewable energy?

Answer 2

Solar
wind
ocean
hydropower
biomass
geothermal
biofuels
hydrogen from renewables

Question 3

What is the EU’s climate target for 2050?

Answer 3

To be carbon-neutral by 2050.

Question 4

What are EU’s 2030 energy targets?

Answer 4

Reduce greenhouse gas emissions 55% (from 1990), promote renewables to 42.5%+, and increase efficiency.

Question 5

Why is regulating power like hydropower needed?

Answer 5

To stabilize electricity supply due to fluctuations in solar and wind power.

Question 6

What is the global installed hydropower capacity in 2024?

Answer 6

1,443 GW.

Question 7

What does total capacity vs. potential mean in hydropower?

Answer 7

Installed capacity vs. untapped hydro potential globally.

Question 8

How does hydropower compare to other renewables in capacity?

Answer 8

Hydropower plants are much larger; the six biggest power plants are hydro.

Question 9

What limits hydropower growth?

Answer 9

Many best dam sites are already developed.

Question 10

Which region consumes ~35% of global hydropower?

Answer 10

Asia-Pacific.

Question 11

What is the largest planned hydropower plant announced in 2025?

Answer 11

A new Chinese plant with 300,000 GWh/year capacity.

Question 12

What are main advantages of hydropower?

Answer 12

Free fuel
low maintenance
high adjustability

Question 13

What are disadvantages of hydropower?

Answer 13

High construction costs.

Question 14

What efficiency do hydropower plants achieve?

Answer 14

80–90%.

Question 15

What is the basic energy conversion in hydropower?

Answer 15

Potential → kinetic → electric power.

Question 16

What is a run-of-river plant?

Answer 16

Uses only a dam reservoir for generation.

Question 17

What is a regulation power plant?

Answer 17

Connected to a regulating basin for flow control.

Question 18

What is a pumped storage plant?

Answer 18

Pumps water to an upper reservoir at night, releases during peaks.

Question 19

What is an off-shore (tidal) plant?

Answer 19

Uses tidal water level changes to generate power.

Question 20

What is the role of a dam or reservoir?

Answer 20

Directs water flow, allows storage, stabilizes output.

Question 21

What is typical in Norway’s hydropower?

Answer 21

Mountain reservoirs, tunnels, small streams with high heads.

Question 22

What is typical in Finland’s hydropower?

Answer 22

Run-of-river plants with max ~30 m heads. Largest is Imatra (168 MW).

Question 23

What are the key components of a hydropower plant?

Answer 23

Dam/reservoir, turbine, generator, and water flow system.

Question 24

What does the output curve of a hydro plant show?

Answer 24

Daily/weekly variation in electricity generation.

Question 25

What is an arch dam?

Answer 25

Curved, strong, efficient for narrow valleys.

Question 26

What is a gravity dam?

Answer 26

Heavy straight structure relying on mass.

Question 27

What is an arch-gravity dam?

Answer 27

Combines arch strength and gravity weight (e.g., Hoover Dam).

Question 28

What is a barrage dam?

Answer 28

Allows gates to open/close for water flow.

Question 29

What is an embankment dam?

Answer 29

Made of rock or earth-soil material.

Question 30

What are the three main flow types of turbines?

Answer 30

Radial (Pelton) - jet turbine axial (Kaplan) mixed (Francis).

Question 31

What heads are Pelton turbines suitable for? What is the turbine efficiency? And what is a typical unit size?

Answer 31

High heads, 300–2000 m. ~90%. <200 MW

Question 32

What head range is suitable for Francis turbines? What is the turbine efficiency? What is the largest unit size?

Answer 32

2–300 m (up to 400 m). Up to 90% Up to 800 MW

Question 33

What is a Kaplan turbine? What is the head range? Turbine efficiency? And unit size?

Answer 33

A propeller turbine with adjustable blades. Below 50 m Over 90% at 40-100% power range Up to 400 MW

Question 34

How do turbine efficiencies compare?

Answer 34

High overall, but differ significantly at partial loads.

Question 35

What is the principle of pumped storage?

Answer 35

Pump water up at night (low demand), release during peak demand.

Question 36

Which turbine types are used in pumped storage?

Answer 36

Deriaz or Francis turbines.

Question 37

What is Pyhäsalmi mine considered for?

Answer 37

Pumped storage hydro power plant. With a planned powerhouse capacity of 200-600 MW.

Question 38

How deep is the lower reservoir in Pyhäsalmu mine?

Answer 38

About 1500 m deep.

Question 39

What are the four main tidal power methods?

Answer 39

Tidal stream generator tidal barrage dynamic tidal power tidal lagoon

Question 40

What is a tidal stream generator?

Answer 40

Underwater turbines similar to wind turbines.

Question 41

What is dynamic tidal power (DTP)?

Answer 41

Long barrier perpendicular to coast, no enclosed area.

Question 42

What is a tidal lagoon?

Answer 42

Artificial reservoir similar to a barrage but man-made.

Question 43

Why is hydropower sustainable (name 3 reasons)?

Answer 43

Renewable water source no greenhouse gas emissions improves grid stability

Question 44

How does hydropower support other renewables?

Answer 44

Provides regulating and backup power.

Question 45

What benefits does hydropower bring to society?

Answer 45

Clean affordable electricity freshwater storage urban development support