Lecture Notes: Hydroelectricity

Objectives

• Describe the use of hydroelectricity in power generation.
• Describe the environmental effects of hydroelectricity.
• Practice justifying a proposed solution.

Key Concepts

Basics of Hydroelectricity

• Generated from the kinetic energy of moving water.
• Water moves past a turbine, spins it, and powers a generator to produce electricity.
• Can be powered by natural river currents, ocean tides, or falling water through a dam.
• Largest renewable energy source globally.
• Main producers: China, Brazil, and the United States.

Methods of Generating Hydroelectricity

Water Impoundment (Dams)

• Most popular method.
• Involves storing water behind a dam to create a reservoir.
• Controls water flow and electricity production rate.
• Benefits include flood control and economic benefits from tourism.
• Issues: displaces ecosystems and causes sedimentation.

Run-of-River Systems

• Use smaller dams and divert water through man-made channels.
• Less impact on ecosystems and allows natural sediment flow.
• Generates less electricity and is dependent on river levels.

Tidal Energy

• Utilizes predictable ocean tides to spin underwater turbines.
• Limited to coastal areas.

Environmental and Ecological Impacts of Dams

• Flooding of habitats behind dams.
• Conversion of rivers to lakes alters ecosystems.
• Sediment buildup impacts upstream and downstream ecosystems.
• Deprives downstream ecosystems of nutrients.
• Alters water temperature and oxygen levels, affecting aquatic life.

Economic Impacts

• Relocation of homes and businesses.
• High initial construction costs.
• Job creation in construction, operation, and maintenance.
• Loss of ecosystem services in downstream areas.

Solutions and Innovations

Fish Migration Solutions

• Fish Ladders: Cement steps/pools enabling fish to bypass dams.
• Salmon Cannons: Tubes that transport fish over dams.

Benefits of Hydroelectric Dams

• No greenhouse gas emissions during electricity generation.
• Reliable and consistent electricity production.
• Economic benefits from tourism and job creation.
• Flood control allows safer human settlements.

Practice FRQ

• Explain two benefits, other than agriculture and recreation, that people gain from constructing dams on rivers.