Environmental Consequences
The energy source we choose would depend upon on the following factors:
- The ease of extracting energy from that source.
- The economics of extracting energy from the source.
- The efficiency of technology available.
- The environmental damage that will be caused by using that energy source.
Example 1.
Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel than CNG? Why or why not?
Answer:
Yes, hydrogen can be considered cleaner than CNG as burning of hydrogen produces water, whereas burning of CNG produces carbon dioxide which is a greenhouse gas and hence a pollutant.
Life of Energy Sources
Sources of energy can be classified as renewable and non-renewable sources. Sources that will get depleted some day are said to be exhaustible sources or non¬renewable sources of energy.
Renewable and Non-renewable Sources of Energy
| Renewable Source | Non-renewable Source |
| The sources of energy which are likely to be available for a long time and are inexhaustible. For, ex. solar energy, wind energy, ocean waves and biogas. | The sources of energy which have taken a very very long time for their formation and cannot be replaced once they are exhausted. For, ex, Fossil fuels like coal, petroleum; and natural gas |
Use of Wood as a Fuel
Although wood is a renewable source of energy since trees can be replenished, but a tree usually takes more than 15 years to mature and moreover large scale cutting of trees for obtaining firewood causes environmental problems.
Example 1.
On what basis would you classify energy sources as
(A) renewable and non-renewable?
(B) exhaustible and inexhaustible?
Are the options given in (A) and (B) the same?
Answer:
(A) Renewable sources of energy are the sources which can be replenished over a reasonable period of time naturally, whereas non-renewable sources are those sources of energy which take a very long time for replenishment. Examples of renewable sources are water and solar energy whereas coal and petroleum are non-renewable sources of energy.
(B) Exhaustible sources are the sources of energy which are limited and may get exhausted, whereas inexhaustible sources are those sources of energy that are unlimited and hence may never get exhausted. Examples of exhaustible sources are coal and petroleum whereas water and biomass are examples of inexhaustible sources of energy.
Yes, the options given in (a) and (b) are the same, as they ultimately refer to the same sources of energy