Solar energy has become an increasingly popular source of electricity for homeowners. With zero emissions, impressive durability and most importantly, excellent savings, it’s no wonder that solar panels have become an accessible source of power. For those interested in understanding the mechanism behind the generation of solar energy, let’s dive into what makes solar panels tick.
The silicon solar cell technology used in the solar panels we use today has existed for almost 70 years. Back in 1954, the silicon solar cell had an efficiency rate of 1%, practically useless compared to the average 26% efficiency we see today. And while efficiency is perhaps the singularly most crucial figure people compare when choosing solar panels, many don’t quite understand the science behind how solar panels produce their energy and therefore, their efficiency.
How do solar panels work?
In simple terms, solar panels absorb solar radiation and turn it into usable electricity. Each solar panel consists of between 32-96 solar cells in a series string. Each solar cell generates electricity and contributes to the overall wattage of the solar panel. The solar cell creates an electric current when sunlight hits its surface, which is usually made of a layer of one semiconductor material (usually silicone) and a second, different semiconductor (usually metal), along with a top layer of glass. Electrons are knocked off from the silicone atoms generating a small voltage which then flows into the solar inverter, where it is transformed into useable alternate current electricity.
While the process of generating solar energy is much the same in any solar panel, there are a few things that differentiate a panel’s ability to generate electricity. Many advancements in technology have been made in recent years to boost the wattage of solar panels whilst making them compact enough to have a wide application. Along with residential solar panels, solar energy has a variety of applications including powering street lights, supplementing electrical grids, and heating water.
Monocrystalline Vs Polycrystalline solar panels
There are two different types of solar panels, monocrystalline and polycrystalline panels. Both are widely available for residential solar, though they differ from one another in fundamental ways. Generally speaking, monocrystalline solar panels are famous for their higher efficiency rates but tend to be more expensive. Polycrystalline solar panels invented 30 years after monocrystalline solar panels, are generally less efficient, but are less expensive. In order for any homeowner to make a decision on which solar panel to employ, they must first look into how each solar panel differs in terms of electricity generation.
Both monocrystalline and polycrystalline solar panels use silicon as their semiconductor material. This is because silicon is extremely durable, non-toxic, and is one of the most abundant natural materials on earth besides oxygen. Since the availability of silicon isn’t an issue, solar panels are affordable for homeowners looking to invest in renewable energy.
Monocrystalline solar panels can be easily identified by their dark appearance. Monocrystalline solar panels are created using a silicon ingot. A silicon ingot is a single, homogenous cylinder of pure single crystal silicon. This cylinder is then sliced into many wafers which create the basis of a solar cell. Each wafer is physically “roughened” to allow for more refraction of light and therefore increased efficiency. The process of producing a single crystal silicon ingot is extremely delicate and lengthy, which contributes to the higher price point.
Polycrystalline solar panels are instantly recognizable by their dark blue hue. They are also manufactured using pure silicon, but the process of creating a polycrystalline solar cell is much more straightforward than a monocrystalline cell. Instead of creating a cylindrical ingot, the pure silicon is left to cool and crystalize. Later, it is heated and poured into cubic growth crucibles. Once solidified, these cubes are cut into wafers, polished and roughened the same as with monocrystalline solar panels. Since each polycrystalline solar cell is made up of multiple crystals, there is less space for electrons to move and generate electricity, contributing to a lower efficiency rate and resulting in lower cost. However, these panels still generate enough electricity to suit the needs of homeowners.
In recent years, the scientific community has made significant advancements that increase the efficiency of solar panels-perovskite solar crystals could replace silicon as a cost-effective and highly efficient semiconductor material in the commercial production of solar panels. Unfortunately, the technology is not currently available for commercial production and is not cost-effective, but homeowners may one day have an even more efficient solar panel to look forward to.
Can solar panels generate electricity continuously?
Now that you’ve understood how solar panels generate electricity, you’ve probably realized that the key to the whole process is a reliable source of sunlight. You may wonder if solar panels generate electricity during the night. In reality, the only chance a solar panel could generate any amount of energy at night is if they come into full contact with the sunlight reflected by the moon on a cloudless night. The amount of power generated would be extremely low, not enough to power a residential building. Because of this, solar panels are a fundamentally intermittent source of power. However, that doesn’t mean homeowners can’t use solar energy at night. Thanks to the invention of solar batteries, solar energy can be stored in its direct current form and then be converted into alternate current later as the battery is discharged.