By Mark Johnson
In today’s world of escalating utility costs, self-storage owners are looking for ways to decrease their energy usage or pay less for the energy used. Solar energy has emerged as a very viable way to do both. There’s a high degree of interest in solar and, at the same time, a common lack of understanding of how it works and how to reap the benefits. This short article will provide some answers.
How Does Solar Work?
Most people are aware of what a solar panel, or module, looks like: a black or black and silver rectangle about 39 by 66 inches. These modules are grouped into what are called "strings," each consisting of eight to 12 panels. The strings are combined and terminate in an inverter. The electricity that enters the inverter as DC (direct current) power exits the inverter as AC (alternating current) power and feeds into the utility system, called the grid.
The purpose of the solar module is to turn sunlight into electricity. The function of the inverter is to convert that electricity to AC power, which is used by the grid and your storage facility. AC power is used by your lights, computer and elevators, for example.
Sunlight is converted to electricity via solar cells, small, square-shaped panel semi-conductors made from silicon and other conductive materials in thin film layers. Sunlight is composed of miniscule particles called photons. When it strikes the silicon atoms of the solar cell, the photons transfer their energy to loose electrons, releasing them from the atoms.
But freeing up electrons is only half the work of a solar cell. It then groups these electrons into an electric current. This involves the creation of an electrical imbalance within the cell, which acts a bit like a slope down which the electrons will flow. This imbalance is made possible by the internal organization of silicon.
Silicon atoms are arranged in a tightly bound structure. By squeezing small quantities of other elements into this structure, two different types of silicon are created: n-type, which has spare electrons, and p-type, which is missing electrons and has “holes” in their place.
When these materials are placed side by side inside a solar cell, the n-type’s spare electrons jump over to fill the gaps in the p-type. The n-type becomes positively charged and the p-type becomes negatively charged, creating an electric field across the cell. Because silicon is a semi-conductor, it can act like an insulator, maintaining this imbalance. As the photons dislodge the electrons off the silicon atoms, this field drives them along in an orderly manner, providing the electric current required.