Hydro Energy

What is hydro energy?
70% of the earth’s surface is covered with water in the form of oceans, lakes and rivers. Early waterwheels driven by the power of flowing water was one of the earliest forms of energy harnessed to do mechanical work. Water or hydropower is a renewable source of energy.

Hydro energy is all about taking energy from moving water so we can use this energy from three different sources:

• The waves which you can see at the seaside
• The tides which come in and go out on the beach
  
• Water stored up in dams

Hydro energy is one of the oldest forms of power and watermills have been used to grind corn for hundreds of years. These days we can build dams to store energy in the water so that when we need it the water can be released from the reservoir (looks like a lake) to turn a turbine to make electricity. The build up of water in the reservoir creates pressure and stores up lots of energy in the water so that when the gates are opened, the turbines turn very fast to make electricity.

Advantages of hydroelectricity

• It is renewable because we have lots of rain throughout the year.
• It doesn’t cause any pollution when the electricity is made.
• It can be switched on and off when needed, making it more reliable than wind or solar energy.

Disadvantages of hydroelectricity

• Hydroelectricity schemes are expensive to build and because of the size of them they take a long time too.
• Only certain areas are suitable for hydro systems and there is a risk that homes in the area around the system may be destroyed.
• Areas which have wildlife nearby can be damaged and river life can be affected when the land is flooded to make reservoirs.

Wave energy

Waves are formed by the wind blowing across the surface of the sea. Waves can travel 1000’s of miles before they reach the shore full of energy. This wave energy can be used to make electricity.

How does wave energy work?

• Lines of boxes each with a turbine inside are anchored away from the shore
• The movement of the waves forces air up through the turbine. The turbine is then forced to spin and turns a generator which produces electricity.

Advantages of wave energy

• It is a renewable form of energy caused by wind so it will not run out.
• The machines do not spoil the landscape and do not cause pollution because they are under the sea.
• The UK has lots of coastline and big waves coming from the Atlantic Ocean.

Disadvantages of wave energy

• Storms at sea can damage even strong machines.
• Rust, seaweed and barnacles can cause problems with the machinery.
• Warning systems have to be made so that ships know to stay away from the turbines.