Solar Power
It’s a common question I get from the inquisitive: “How do solar panels work?” It’s a hard question to answer in limited time, but I’ll do my best here.
Typically a 250w solar panel is made up of 60 cells, each cell measures about 150mm. The working of these individual cells is the basic explanation of how a solar panel works.
The PV cells consist of Silicon, which is a semiconductor. Silicon itself does not create electricity, so a bunch of Chemists and Physicists came up with an ingenious idea. They cut the silicon into two thin layers and “doped” the silicone with impurities. They added the element Phosphorous one layer and Boron into the other. When doped with Phosphorous, the resulting silicon is called N-type (“n” for negative) because of the abundance of free electrons. The other piece of Silicon, doped with the Boron, becomes a P-type Silicon (“p” for positive). Instead of having free electrons, the P-type has free openings and carries the opposite (positive) charge.
Because Boron requires electrons, and Phosphorus can emit electrons, the two create a tension, or an electrical field. This electrical field is measured in voltage. When light (in the form of photons) hit the solar cell, the electrons start to move. If we then provide an external current path,electrons will flow from the P side to the N side, charging inverters, illuminating lights and powering appliances for us along the way.
This electron flow provides the current, and the cell’s electric field causes the voltage. With both current and voltage, we have power, which is the product of the two.
Creating a solar cell then becomes a fairly simple science! The production of these cells into panels in mass quantities becomes the challenge. Some companies have succeeded in the challenge – but more have failed. But that is for another blog.
Mark
