Many people focus primarily on price when they make purchasing decisions for their solar panel requirements. However, there are several pertinent factors to consider when choosing the most efficient solar PV panel for the home.
There are basically 3 types of solar panels although these may be sub-divided into further sub-categories.
Mono-crystalline solar panels use cells made of single large crystals, which are cut from ingots. Considering power output, these panels cover the smallest area, making them ideal for people with limited space. Their average efficiency is between 12% and 15% and they are usually warranted for between 20 and 25 years. These panels are usually blue-grey.
Poly-crystalline panels use cells made of silicon having several small crystals. These panels are more common because they provide a good balance between performance and price. They have an average efficiency of between 11% and 14%. Their colors range from dark blue to black, with the appearance of shattered glass.
Amorphous solar panels use the least amount of silicon, which is spread on large plates. This is why they are also known as thin-film solar panels. Although the panels are relatively cheap, they are less efficient than the previous 2 types, with an average efficiency of between 5% and 6%. They tend to be relatively large. However, they offer flexibility that makes them ideal for specific uses where flexibility matters.
There are also newer types of panels that are still less popular. Concentrating panels use mirrors and lenses to focus sun’s rays onto individual cells. Since solar cells produce electricity in direct proportion to the solar energy they absorb, this technology leads to the use of fewer cells. These types of panels are especially ideal for areas that receive relatively less solar energy.
Another new technology involves the use of special materials that absorb a wider spectrum of solar energy. These are known as Group III-IV solar panels, which have efficiencies of about 25%. However, they are still used for special purposes because of their high costs.
Users can calculate the efficiency of solar panels by dividing the maximum power rating (Pmax) by the area (A) the panel covers. This helps in calculating energy density or power per unit area. This calculation is important when considering the available space for installing the solar PV panels, usually on the roof. Other important considerations include the total power requirement and durability of the panels.