Light contains energy, which we normally feel as heat, but some materials can transform this energy into an electric current instead. Solar panels take advantage of this property and use photovoltaic cells made of substances, such as silicon, which can cause the conversion to happen.
Wires running through the cell take the electricity from the cell and back to the house, or battery, to be used as a power source.
Silicon is actually a poor conductor, but it’s a good substrate, or holder, for better conductors. In a typical photovoltaic cell, two layers of silicon, one doped with a negatively charged substance, the other with a more positive material.
The interface of these two different silicon-held substances creates an electric field where the negative and positive materials attract each other. The electrons move between the two materials trying to achieve a neutrally charged state, but this movement only takes place at the closest junction of the layers.
When the energy from sunlight hits the cell, it begins “knocking loose” electrons from the other parts of the silicon. These electrons move around randomly until they happen to reach the junction of the silicon layers. Since the space in the junction is very limited, the electrons are pushed towards the metal wires, generating electricity.
Newer materials that can be shaped into thinner films are becoming more popular, but they are even less efficient than silicon at converting energy into electricity.
The direct current coming from the photovoltaic cell is sent to an inverter within the house that converts the direct current (DC) into alternating current (AC) that we use to power our appliances.
To take advantage of solar power, households often need several panels and sufficient sunlight to power them. Energy-efficient homes that produce more electricity than they use can often sell back the excess power to their power company, making the panels even more affordable.
Solar vs. Fossil Fuels
Despite its inefficiency and expense, the popularity of fossil fuels is increasing. Fossil fuels are not only a limited resource, mining them is destructive to the environment and the waste produce form burning fossil fuels is damaging the air and water. Solar technology is currently one of the cleanest power sources available and the rising demand is expected to lower cost, and encourage the creation of more efficient photovoltaic cells.
As manufacturers create more energy efficient appliances, and solar applications continue to grow, houses fully powered by solar panels, or other green energy sources, are soon to become the norm.