Alternate energy

Solar energy


  • Solar energy is obtained from sunlight.

  • Solar energy has been used by humans for a long time for uses such as heating, cooking food, removing salt from seawater and drying clothes.

  • These days it is also used to create electricity. As technology has improved, solar power costs have decreased and it has become a more viable alternative, competing with energy sources such as coal and oil.

  • While solar power is becoming more efficient, it only provides a small fraction of the world’s energy supply.

  • Solar cells convert light energy into electricity.

  • Solar cells are also called photovoltaic cells.

Wind enegry

  • Wind power involves turning energy from the wind into other forms of useful energy.

  • Wind power can be harnessed in a number of different ways. For example, windmills create mechanical energy, sails move boats and wind turbines generate electricity.

  • Windmills have been around for a long time, they were used in Persia (Iran) as far back as 200 B.C.

  • Wind energy is clean and renewable.

  • Large groups of wind turbines are called wind farms.

Geothermal energy

  • Geothermal energy is made inside the Earth.

  • The world geothermal comes from Greek words meaning ‘Earth’ (geo) and ‘heat’ (thermos).

  • The technology behind geothermal electricity generation has improved substantially but it still only provides a fraction of world electricity generation.

  • Geothermal power is clean, reliable and cost effective but its availability is often limited to areas near tectonic plate boundaries.

  • Geothermal power plants in the Philippines and Iceland contribute around 30% of their electricity production. In the USA it is less than 1%.

Nuclear energy

  • Nuclear power uses fission (splitting atom nuclei) to produce energy.

  • Nuclear fusion (joining atom nuclei) also has potential for energy production.

  • Around 6% of the world’s energy and 14% of the world’s electricity is produced by nuclear power.

  • There are over 400 nuclear power reactors in use around the world.

  • Around 30 different countries have operational nuclear reactors.

Hydro energy

  • Hydropower uses the energy of moving water for a variety of useful applications.

  • Hydroelectricity generates electricity by harnessing the gravitational force of falling water.

  • In 2006, hydroelectricity supplied around 20% of the world’s electricity.

  • Most hydroelectric power stations use water held in dams to drive turbines and generators which turn mechanical energy into electrical energy.

  • The largest hydroelectric power station in the world is the Three Gorges Dam in China.

Biomass energy

  • Almost half of the renewable energy produced in the United States comes from biomass sources, like wood and paper products.
  • In Iowa and Wisconsin, biomass energy from landfills and dairy farms is being used to make electricity.
  • In southern Iowa, a power plant is using a crop called switchgrass to make electricity.
  • The word "biomass" means natural material.
  • If you've ever been near a campfire or a fireplace, you've witnessed biomass energy through the burning of wood.
  • Biomass has been around since the beginning of time when man burned wood for heating and cooking.