Question

Make a list of conventional and non-conventional sources of energy. Give a brief description of harnessing one non-conventional source of energy.

Answer 1

Conventional sources of energy are fossil fuels like coal, oil, wood, water, wind and uranium.
Non-conventional sources of energy include:

• Solar power
• Hydro-electric power (dams in rivers)
• Wind power
• Tidal power
• Ocean wave power
• Geothermal power (heat from deep under the ground)
• Ocean thermal power (the difference in heat between shallow and deep water)
• Biomass (burning of vegetation to stop it producing methane)
• Biofuel (producing ethanol (petroleum) from plants

Below is the working of a solar cell which harnesses solar energy:
A solar cell is an electronic device which directly converts sunlight into electricity. Light shining on the solar cell produces both a current and a voltage to generate electric power. This process requires firstly, a material in which the absorption of light raises an electron to a higher energy state, and secondly, the movement of this higher energy electron from the solar cell into an external circuit. The electron then dissipates its energy in the external circuit and returns to the solar cell. A variety of materials and processes can potentially satisfy the requirements for photovoltaic energy conversion, but in practice nearly all photovoltaic energy conversion uses semiconductor materials in the form of a p-n junction.
The basic steps in the operation of a solar cell are:
the generation of light-generated carriers;
the collection of the light-generated carries to generate a current;
the generation of a large voltage across the solar cell; and
the dissipation of power in the load and in parasitic resistances.
Below is the diagrammatic representation.