Tommy Teaches: How PVs Work (Part 1)
Okay, here we go ladies and gents.
I struggle to learn when I only consume information. Gunning for understanding, you must create something out of the information.
So why not write a short essay to strengthen the understanding of a subject? You also train your writing, communication, and storytelling ability like that!
Global warming's kind of aggressive. I remember the Swiss winters of my childhood. We have much less snow now.
Just to make it clear: when we look at historical data, the planet's getting hotter. There's so much discussion about the perpetrator, be it the planet's cycle itself, we as the human species, or a mixture of both, we forget what's important: it's getting hotter. So it makes sense to me to not use up mental prowess on who's at fault, give blame, and then smugly move on. We need to figure out how we get out of this situation.
Which is what I'm going to do now by explaining to myself how photovoltaics (PVs) work.
But why PVs?
It seems that CO2, as a greenhouse gas, is a contributor to global warming, maybe even a catalyst.
Energy is one of the most fundamental enablers of human welfare. Without it, we can't produce medicine, cook food, and watch our favorite TV show for the hundredth time. We can't even have unnecessary discussion about whether climate change is real or not over the internet! Bummer, so that's why energy's pretty darn important.
Energy production is also one of the main contributors of CO2 emissions.
But renewable energies don't have that problem. After some CO2 emissions happen during their manufacturing process (wind turbines, PVs, hydro turbine-generator systems, etc.), there are negligible or none at all after these technologies start producing energy. Here's the problem, though:
I don't know how they work from first principles. I'm still in the learning phase here, so it will be very basic. But that's the beauty of it! So here we go: how do PVs work?
How Does A PV Create Electricity?
If you've looked up at the blue thing called the sky in the last few months, you'll have seen a very bright ball known as the sun (people who live in Zurich in winter: neglect this statement). The sun radiates light, and light is made out of tiny particles known as photons. These photons hit the PV. But think of it more as a bombardment of photons: billions of photons slam against the outer wall of the PV (the solar glass) simultaneously. Yet the true magic lies underneath: semiconductors. The technology that makes a computer work is also the reason why PVs can create electricity. These semiconductors are made out of silicon. One of these rockets from the sun will hit the right spot on the silicon, and an electron, another particle, is knocked loose. Instead of bouncing all over the place and letting these beauties go to waste, the engineers built in a p-n junction ("p" standing for positive, while "n" standing for negative). Think of the p-n junction as the shepherd of the freed electrons, leading them to go into the right direction. This creates an electrical current, which then flows along the built-in wires. But before these wires can lead the generated electricity straight to your house, there's a problem. The kind of electrical flow your house runs on is usually an alternating current (AC), but the electrical flow from the PV system is a direct current (DC). Think of it as a language your house can't quite understand and thus not use, so we need a translator. This translator is called the inverter. This device changes the current from DC to AC, and now you can use the electricity for everything you want in your home! And so, we're able to harness the power of the humongous fusion reactor in the sky.
This was my first try at a short essay for understanding a subject I'm extremely interested in. Many more will follow, since I can already feel that it worked wonders!
Read you next week!
