Energy from various sources is considered to have been derived from the Sun. Do you agree? Justify your answer.
Yes. Sun is the ultimate source of energy. All forms of energy arc derived either directly or indirectly from solar energy. Solar energy refers primarily to the use of solar radiation for practical ends.
Non-renewable sources of energy: Sunlight absorbed by the oceans and land masses keeps the surface at an average temperature of 14 °C. By photosynthesis, green plants convert solar energy into chemical energy, which produces food, wood and the biomass from which fossil fuels are derived.
Renewable sources of energy: They are indirectly derived from solar energy such as:
1. Hydroelectricity: Energy is formed from flowing water when water from various water bodies like lakes, rivers, seas evaporate due to solar energy. They bring rainfall. Solar energy also evaporates water that falls as rain and builds up behind dam, where its motion is used to generate electricity via hydropower.
2. Wind energy: Wind is produced due to the uneven heating of the earth’s surface by the sun rays. Moving wind has large amount of kinetic energy’. Mechanical or electrical power is created through the kinetic energy of the wind.
3. Ocean thermal energy: Sun is responsible for the difference between the water at the surface and water in the depths of oceans and seas.
4. Wave energy: The winds cause waves on the surface of the ocean (and on lakes). Wind is produced due to the uneven heating of the earth’s surface by the sun rays. The wind transfers some of its energy to the water, through friction between the air molecules and water molecules. Stronger winds (like storm surges) cause larger waves. This difference in temperature is exploited to obtain energy in ocean-thermal-cnergy conversion plants.