Renewable energy comes from the sun, the wind, from water and from plants. Getty Images

Renewable energy comes from the sun, the wind, from water and from plants. Getty Images

Renewable energy is any form of energy that comes from natural sources

Sunlight to produce solar electricity

Wind to produce wind power

Rainwater to produce hydro-electricity

Tides or waves for tidal power.

Geothermal is heat that comes from inside the Earth, the steam and hot water is used to produce geothermal power. The steam and hot water are used to generate electricity at a power station. The steam and heat are always available, they are clean and safe, and won't run out.

Steam and hot water from inside the Earth can be used to make electricity.

Steam and hot water from inside the Earth can be used to make electricity.

Biofuels such as ethanol can be produced from sugar cane and other crops to replace some of the petrol we use as the energy for cars and trucks and other forms of transport. The ethanol is mixed with petrol. These things can also be used to make ethanol: corn, rice, potato skins, bark and even grass clippings. These plants can be grown again and again. 

Another form of biofuel is biomass. It is material such as wood, garbage and waste from farms and farm animals' poo (manure) that we can change into energy. When biomass rots it produces methane gas. Methane gas can be used to make natural gas which is a common source of energy. The methane can be used to make electricity. 

Problems with biofuels and biomas

  • Burning garbage and waste will cause air pollution and release green house gases. 

  • The land cleared for growing corn and sugar cane can reduce habitats and destroy ecosystems.

  • The land used for growing biomass could be used to grow other crops for food.

  • Growing biomass can use fertilisers and other chemicals that can cause water pollution.

Tidal power

The energy of ocean water can be used to make electrical energy.

The energy of ocean water can be used to make electrical energy.

The power of the tides can be used to generate electrical energy. Tides are caused by the pull of the Moon's and the Sun's gravity on the ocean. This pulling causes great bulges of water towards the moon and the sun.  As the Earth turns there are two high tides and two low tides each day when water will rise for about six hours, then fall for six hours. Throughout the day the sea level is rising and falling.

All the energy of rising and falling water can be used to make electrical energy. Tidal turbines spin and a generator produces electrical energy. The electricity then travels through wires to homes and other places where people need it. 

Some advantages of renewable energy

  • Renewable sources of energy don't get used up or run out. They are supplied or replaced by nature and are always available.
  • Climate change, pollution of the environment, and the high cost of oil are all reasons why governments are beginning to make greater use of these renewable energy resources. 
  • Renewable energy has minimum impact on the environment and most don't release dangerous greenhouse gases into the atmosphere that are said to cause global warming or climate change.

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