Solar energy is radiant light and heat from the Sun that is harnessed using a range of ever-evolving technologies such as solar heating, photovoltaics, solar thermal energy, solar architecture, molten salt power plants and artificial photosynthesis.

Wind energy (or wind power) refers to the process of creating electricity using the wind, or air flows that occur naturally in the earth's atmosphere. Modern wind turbines are used to capture kinetic energy from the wind and generate electricity.

Hydroelectric power exploits the water cycle, gravity, and the density of water to generate electricity.  Since water is much more dense than air,hydroelectric power is able to harness the mechanical energy from water at a much higher efficiency than a wind turbine can from the less dense air.