Most of the energy we use is obtained from fossil-fuel coal, oil and natural gas.
The wind is used to turn windmill like turbine which generate electricity directly from the rotating motion of their blades.
Motion of waves
This can be used to move large floats and generate electricity.
A very large number of floats is needed to produce a significant amount of electricity.
Dams on tide estuaries trap the water at high tide.
when the water is allowed to flow back at low tide, it can turn turbines to generate electrical energy.
Dams can be used to store water, which is allowed to fall in a controlled way that generate electricity.This is done in hydroelectric power.
Geothermal power is obtained using the heat of earth.
In certain parts of the world, water forms hot springs which can be used directly for heating.
During this process the small nuclei of hydrogen atoms join to make larger nuclei (helium nuclei) and an enormous amount of energy is released. This is the source of energy in sun.