Energy from Water (Cambridge (CIE) O Level Physics): Revision Note

Hydroelectric Dams

• When water is stored above ground level it has energy in its gravitational potential store

• This energy can be transferred to kinetic energy if the water is allowed to flow down the slope

• Flowing water turns the turbine to generate electricity

A Hydroelectric Dam Operating

A hydroelectric dam transfers energy from the gravitational potential energy store of the water to its kinetic energy store mechanically to generate electricity

Advantages

• Can respond to demand so is reliable and available

• Can generate large scale amounts of electricity

Disadvantages

• Need to flood valleys to build which destroys habitats, towns and villages

• The pumping systems can release large amounts of greenhouse gases

Wave and Tide Power

• The rise and fall of waves or the tide can be used to turn a turbine and generate electricity

Turbines using Wave Power

Underwater turbines generate electricity

Turbines using Tidal Power

Tidal Barrage

Advantages

• No pollution

• Reliable and can produce a large amount of electricity at short notice

• Renewable energy resource

• Small systems are being developed to provide electricity for small islands

Disadvantages

• Expensive to build

• Damages fragile habitats

• Very few suitable locations

• The technology is not advanced enough for large scale electricity production