Energy from Water (Cambridge O Level Physics)

• 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

• 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