What is Solar Energy? How does Solar Panels work?
What is Solar Energy | How solar panel works | Sundaygrids
Here’s a stat that is quite well known at this point (and still pretty hard to wrap our heads around); the energy that hits the surface of the earth in an hour and a half is sufficient to supply the global energy demand for a year. We are talking about energy for everything; from lighting up our megacities to making food for 8 billion people.
Now imagine, if we could build a bucket to capture even a fraction of this solar energy, it would have phenomenal implications of how we run our societies and economies. And the good news is, we have some tricks to bottle up this light, and we are getting better and better at it.
Since the beginning of electric systems, most of our power is made from running water or steam over turbines (basically super huge fans) that spin and produce electricity (thanks to some neat trick Mr. Faraday found). Fossil fuels such as coal and gas are ways to heat the water to become steam for the turbines in our power stations.
This is how solar concentrators, our first kind of light bucket works as well; Solar concentrators are large mirrors that reflect and focuses the sunlight to something similar to a water tower. The heat turns water into steam, which is directed to turbines, and zap! we get power. These concentrator mirrors are spread across acres of land and aerial shots of these farms often quite a sight to behold.
Our second kind of light bucket is quite special, and yes, we are talking about solar panels (or to be more accurate, photovoltaic modules). What makes solar panels stand apart from every other energy system so far is that it converts electricity directly. No spinning turbines involved at all. Just find a sunny spot to place them, and on the other end connect wires and electricity begins to flow. Easy peasy.
And this is huge news; because since you don’t need large turbines, instead of building these massive power stations, you can put them anywhere in any form and shape, on your roof, in your calculators (and even in space). Also, since there aren’t any moving parts, these panels can last for a really long time, often 20 to 25 years.
Here’s how they work;
When sunlight hits a photovoltaic cell, they excite the electrons in those cells. If conductors are joined to the positive and negative sides of the cell, for the electrons to flow, they produce an electric current. Many cells together form a solar module, and multiple modules are often wired together to form a solar system. The more panels you add to your system, the more energy you could produce to power larger appliances. In most cases you can’t directly wire a solar panel to the appliance, it has to go through an intermediary called an inverter. Here’s why →
The power produced from the panels needs wires at the positive and negative ends of a cell to push electric current through, this is called Direct Current (DC), while the regular wall outlet sockets in our homes use an Alternate Current (AC). While solar panels generate DC electricity, most electricity consumers need AC electricity to power their buildings. The inverter’s function is to convert the electricity from DC to AC, making it available for everyday use. After the electricity is transformed into a working state it's sent from the inverter to the electrical panel, and distributed throughout the building. The electricity is now readily accessible to power lights, appliances, and other electrical devices with alternating current.
Though we use the term solar panels broadly, there are a bunch of subcategories among them. The selection of materials and production cause differences in appearance as well as performance between each kind of solar panel. And while there are quite a few of them at an experimental level, they are roughly four types you can find at your nearby installer;
Monocrystalline solar panels: If you see a solar panel with black cells, it’s presumably a monocrystalline panel. These cells appear black thanks to how light interacts with the pure silicon crystal. Being made out of pure silicon ingots, they have the maximum efficiency among all types.
Polycrystalline solar panels: Unlike monocrystalline solar cells, polycrystalline solar cells tend to possess a bluish hue to them because of the sunshine reflecting off the silicon fragments within the cell in a distinct way.
Although it is less efficient than the single-crystal cells found in monocrystalline panels and requires more modules to achieve the same performance, polycrystalline panels are cheaper as manufacturing the silicon cells are cheaper as well as the assembly is cost-effective and easier. Compared to mono, they are more affected by high temperatures and reduces productivity on the hottest days.
Thin-film solar panels: The biggest differentiating factor when it comes to thin-film solar panels is, as their name suggests, how thin and low-profile the technology is. These panels are often slimmer than others by using cells that are roughly 350 times thinner than the crystalline wafers used in typical solar panels.
Thin-film solar panels are less efficient and have lower power capacity than single crystal and polycrystalline solar cell types.
PERC: It stands for “passivated emitter and rear contact” or “rear cell”. PERC solar panels have an additional layer on the rear of the conventional solar cells that allows more sunlight to be captured and have become electricity, making PERC cells more efficient than traditional cells. PERC panels are available in both mono and polycrystalline configurations.
One constraint with solar panels is that being a surface phenomenon, they take up quite a lot of space to install reasonably usable capacity. This makes it hard especially for residential users who might have limited access (and virtually none for those living in residential apartments). The convenient and hassle-free solution to this is Digital Solar; which is a platform where instead of installing panels directly on your roof, you can reserve solar capacity from larger solar farms or commercial installations. You can connect your reserved solar to your power utility account and get savings on your power bill. That way you can keep your roof installation-free, while you lower your power bills with clean energy.