#sreeshanphysics #renewableandnonrenewableenergy #energy

Pg:- 127,128,129

Ch:- 7

Wave power is a renewable energy source that captures energy from the motion of ocean waves to generate electricity.

1. Source of Energy: Ocean waves are created by the wind blowing over the surface of water, transferring kinetic energy into the waves.

2. Mechanism: Wave energy converters (WECs) are devices that capture the energy in waves. Common types include:

   • Point Absorbers: Devices that move with the waves, using this motion to drive a generator.

   • Oscillating Water Columns: Structures that trap air above a chamber; wave motion forces air through a turbine to generate electricity.

   • Overtopping Devices: Structures that capture water from waves and release it through turbines.

3. Advantages:

   • Clean and renewable.

   • High energy density compared to wind or solar.

   • Predictable, as wave patterns follow consistent ocean behavior.

4. Challenges:

   • High installation and maintenance costs.

   • Environmental impact on marine life.

   • Requires specific coastal conditions.

Hydroelectric Power is a renewable energy source that generates electricity by using the gravitational force of falling or flowing water.

1. Principle of Operation

Hydroelectric power is based on potential energy stored in water at a height. When water flows downward, its potential energy is converted into kinetic energy, which is then used to produce electricity.

2. Components of a Hydroelectric Power Plant

1. Dam: Stores water in a reservoir and creates a height difference (head) for potential energy.

2. Reservoir: Holds the water that will be released to generate power.

3. Intake Gate: Controls the flow of water to the turbines.

4. Penstock: A large pipe through which water flows to the turbines under pressure.

5. Turbine: Converts the kinetic energy of flowing water into mechanical energy.

6. Generator: Connected to the turbine, converts mechanical energy into electrical energy.

7. Transformer: Converts the generated electricity into a higher voltage for transmission.

8. Tailrace: Returns water to the river after it has passed through the turbines.

3. Process of Electricity Generation

1. Water is stored in a reservoir behind a dam.

2. The intake gate opens, and water flows through the penstock.

3. The force of flowing water rotates the turbine blades.

4. The turbine drives the generator, which produces electricity through electromagnetic induction.

5. Electricity is transmitted via transformers and power lines.

4. Types of Hydroelectric Plants

1. Impoundment: A dam is used to store water and release it as needed.

2. Run-of-River: Relies on the natural flow of the river without large reservoirs.

3. Pumped Storage: Pumps water to a higher reservoir during low electricity demand and releases it to generate power during high demand.

5. Advantages

• Renewable and sustainable.

• Produces no direct emissions.

• High efficiency (up to 90%).

• Provides energy storage in pumped storage systems.

• Can provide flood control and irrigation.

6. Disadvantages

• The high initial cost for construction.

• Potential environmental impacts (e.g., habitat loss, altered water ecosystems).

• Displacement of communities during dam construction.

• Reliance on water availability, which can be affected by droughts.

Hydroelectric power is widely used globally and plays a critical role in providing clean and reliable energy.