conventional sources of energy are basically of 2 types.
1) Non-renewable energy is a blanket term for sources of energy that rely on consumable materials. Non-renewable energy sources come out of the ground as solids, liquids, and gases.
Examples of Non-renewable energy:
Nuclear energy and its nuclear wastes.
2) Renewable energy sources, or RES, are those energy sources which are not destroyed when their energy is harnessed. Renewable energy sources are distinct from fossil fuels, which must be consumed to release energy. Human use of renewable energy requires technologies that harness natural phenomena, such as sunlight, wind, waves, water flow, biological processes such as anaerobic digestion, biological hydrogen production and geothermal heat.