Question

Why are we looking at alternative sources of energy?

Answer 1

Hint: Not all sources of energy are sustainable and available to us infinitely. And hence, their usage has to be regulated if they are to be conserved for future generations and alternate sources have to be discovered.

Complete answer:
Let us first understand what renewable sources and non-renewable sources are. On the basis of renewable and non-renewable sources of energy we can understand why we need an alternative source of energy.
Renewable resources of energy are those which are replenished naturally while non-renewable resources are those which are limited and may become extinct if used without care.
Classifying the sources as such gives us an insight into the limitations in using certain resources which are available to us in short supply. Coal, petroleum, natural gas etc. are some of the resources of energy which do not get replenished as frequently as they are consumed and hence their use has to be regulated and limited and are classified under non-renewable resources.
As mentioned before, not all sources of energy are sustainable and available to us infinitely. And hence, their usage has to be regulated if they are to be conserved for future generations and alternate sources have to be discovered. The said method of classification gives us a statistical and geographical idea regarding their availability and sustainability. Hence, the usage of resources which are under the danger of possible extinction can be limited. More knowledge and information regarding alternate sources can be acquired and this further aids in locating renewable sources and harnessing them.

Note:
The renewable sources of energy can be used as alternative sources.
Renewable resources are those which are available to use at such a large amount and/or are replenished regularly. Examples of renewable sources are solar energy, tidal energy, geo-thermal energy, wind energy etc.