High School Physics

Renewable Energy Resources & Electricity Generation

Renewable Energy Resources are sources of energy that will never run out. Sources of renewable energy include solar, biofuels, wind, hydroelectric, tidal, wave, and geothermal. Renewable energy resources contribute far less to climate change than fossil fuels and hence these energy resources are becoming more widely used.

Types of Renewable Energy Resources

Renewable Energy Sources include solar, biofuels, wind, hydroelectric, tidal, wave, and geothermal. Here, we will briefly discuss on each of these.

Solar Energy

Electricity generation from solar energy at Solar power plants

  • A solar power station uses the Sun’s energy to generate electricity.
  • At a concentrated solar power plant, mirrors are arranged in circles to focus sunlight onto a central receiver.
  • The heat received in this way is used to boil water and make steam,
  • This steam is used to drive a generator and thus electricity from solar energy is produced at solar power plants.
  • Solar power plants work best in sunny climates and can’t generate electricity at night.

Electricity generation using Solar cells

  • Electricity can also be produced directly using solar cells (photovoltaic cells).
  • Solar cells work best in sunny climates and can’t generate electricity at night.

Wind Energy

Electricity generation from Wind Energy

  • The air in Earth’s atmosphere is warmed by the Sun. This warm air is continually moving.
  • The kinetic energy of the warm air can be captured by wind turbines.
  • The moving wind turbines drive generators, which produce electricity.
  • Wind turbines require suitable weather and must be high above the ground or ocean to work well.
  • Many wind farms are built offshore (in the ocean), where they don’t spoil the appearance of natural landscapes.


Electricity generation from Biofuels

  • In some parts of the world, biofuels are used to power cars rather than gasoline or diesel.
  • Biofuels can be made from fast-growing crops like sugar cane.
  • The sugar is fermented to make ethanol, which can be burned in car engines.
  • Although biofuels contribute less to global warming than fossil fuels, their production takes up land that could be used to grow food and has led to deforestation in tropical areas.


Hydroelectricity generation from water

  • Hydroelectric dams hold back rivers to form artificial lakes.
  • Water from the lake flows through pipes to turbines at the bottom of the dam.
  • The turbines drive generators, which produce electricity.
  • One disadvantage of hydroelectricity is that the natural habitat of the valley is lost when it’s flooded to make the lake.

Wave and tidal energy

Electricity generation from Wave and tidal power

  • Wave and tidal power stations use the motion of seawater to drive turbines placed in water.
  • Wave power is still experimental.
  • Tidal power stations are difficult and expensive to build but can produce large amounts of electricity at predictable times, though not constantly.
  • One disadvantage is that they can change tidal patterns upstream, affecting the wildlife there.

Geothermal energy

Electricity generation from Geothermal energy

  • At a geothermal power station, cold water is pumped deep underground, where it is heated to make steam by energy from Earth’s interior.
  • The steam is then used to drive electricity generators.
  • Geothermal power stations produce very little pollution but work best in volcanically active places.
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