Classify energy resources into two categories. Give two examples of each category.
All the energy sources can be classified into two main categories- ‘conventional’ and ‘non-conventional’ energy sources.
Conventional energy – These include non-renewable sources of energy which are being used since a long time. Examples of these are firewood, cattle-dung cake, coal, petroleum, natural gas, etc.
Non-conventional energy – These are broadly renewable or inexhaustible and do not cause environmental pollution or heavy expenditure. These include solar, wind, tidal, geothermal energy and biogas.