Solar Energy – Electricity
Solar energy is the energy we receive from the Sun. The Sun emits the full range of the electromagnetic spectrum. This page only considers transforming solar energy into electrical energy.
Solar cells are also known as photovoltaic (PV) cells. Solar cells are devices that transform light energy directly into electrical energy.
How do solar cells work?
The general principles by which all solar cells work are:
- Light consists of little ‘parcels’ or ‘packets’ of energy called photons.
- When photons shine on a solar cell, they are absorbed by the cell.
- If the photons have enough energy they cause the cell to release electrons.
- If the photons do not have enough energy, their energy is transformed into heat energy.
- The released electrons enter wires and travel around an electrical circuit.
- The resulting electrical current is in the form of a direct current (DC). This is a current that flows in one direction only.
- If the light is more intense (brighter light) more electrons will be released each second and the electrical current will be bigger. The voltage of the cell will stay the same.
The video below, which was produced by the University of New South Wales, also shows how silicon-based solar cells work.
Types of solar cell
How a solar cell actually works depends on whether it is a silicon-based solar cell or another type of solar cell, such as an organic solar cell (which is made up of plastics), or a dye-sensitised solar cell (also known as a Grätzel cell).
Research teams across the world are doing some very exciting work using different designs and different technologies, including nanotechnology, in the hope of developing solar cells that:
- are more efficient (convert a greater the proportion of the energy from the Sun into electrical energy);
- can be used in a wider variety of applications;
- are more environmentally friendly (made from less harmful substances, consume less of the Earth’s resources, produce less wastes when manufactured);
- cost less.
Some research projects have developed flexible, light-weight solar cells that can be part of clothing or a back pack used by people such as hikers and field workers. Others involve developing windows and roofs that can act as solar panels.