How Does Solar Energy Work?
Most of us know that solar panels convert sunlight into electricity. But few people know exactly how solar energy works.
How does solar energy work? How is it produced? Today, we’re answering all of your questions to give you a better understanding of the nature of solar energy.
The Sun’s Energy is Hitting Our Planet Every Day
The sun radiates an enormous amount of energy every day. That energy radiates across our solar system, our galaxy, and the universe. A tiny fraction of that radiation hits our planet. This energy is absorbed by our land and oceans. It’s because of this energy that our planet is warm and has an atmosphere.
Typically, when the sun’s energy reaches our planet, it gets turned into heat. When light from the sun hits an object, that light gets turned into heat. That’s why you feel warm when you sit in the sun.
However, when light hits certain minerals, that energy gets turned into an electrical current instead. We can harness that electrical current and use it for power.
Silicon and Other Minerals Turn Solar Energy into Electricity
Originally, solar panels used large crystals made from silicon. When light hits silicon, it produces an electric current.
What makes silicon special? The electrons in silicon crystals will become excited when exposed to light. The electrons “get up” and start to move. Typically, electrons just vibrate or jiggle when exposed to light (it’s this vibration that creates heat). With silicon, however, light energy gets turned into electricity.
Silicon panels are less popular today. It’s difficult and expensive to create big silicon crystals. Researchers have found alternative minerals and materials.
Copper-indium-gallium-selenide, for example, is one popular option. These are smaller, cheaper crystals that work in a similar way to silicon. This material is popular because it can be shaped into flexible “films.” That’s why it’s called “thin film” solar technology.
Despite our efforts, copper-indium-gallium-selenide is not as efficient as silicon in terms of turning light into electricity. However, technology continues to improve every year. Solar panels have never been more efficient than they are today.
How Do Solar Cells Work?
We know that certain minerals react with light to create electricity. In order to harness that property, however, we need to make solar cells. A solar cell is a manufactured device that takes the energy of sunlight and converts it into usable electricity.
How does a solar cell work?
Basically, the solar cell is made of a material like silicon or the copper-indium-gallium-selenide we mentioned above. This material is found in the form of many crystals linked together.
In a crystal, the bonds between silicon atoms are made of electrons. When light hits these electrons, one of the electrons in the bond bumps up to a higher energy level. At this higher energy level, the electron can move around more freely than when it was in the bond. Once the electron can move around the crystal freely, we can get a current of usable electricity.
One of the best ways to visualize this is like a bookshelf with two shelves. Before being exposed to sunlight, the crystals in your solar cell are in their normal state. Picture a ball sitting on the bottom shelf. After being exposed to sunlight, these balls bump up to the next shelf. The electrons get promoted to a higher energy level. Once they’re on this energy level, they can’t bump down to the previous level until you spend that energy.
When you’re ready to collect the energy, you take the ball and move it down to the bottom shelf. You harness the energy, then wait for photons of light to bump the ball to the second shelf once again.
Solar Panels Generate DC Electricity
After you install photovoltaic systems and they begin to generate electricity, they’ll only create direct current (DC) electricity. With DC electricity, electrons flow in one direction around a circuit. Most modern electronics, however, require alternating current (AC), where electrons are pushed and pulled.
AC was chosen for most modern power grids because it’s less expensive to transmit electricity over long distances.
In order to use your solar energy, you need an inverter that transfers DC electricity to AC electricity. A solar inverter takes the DC electricity from your solar panel system, then turns it into AC electricity.
Inverters do more than transfer your electricity to usable AC electricity: they also provide ground fault protection and system stats (like voltage and current, energy production, and maximum power point).
Originally, solar panel systems relied on central inverters. In recent years, however, the solar energy industry has made big strides with the invention of micro-inverters. Micro-inverters are optimized for each individual solar panel – not for an entire solar system like a central inverter. This means each solar panel can perform at its maximum potential.
Net Metering
Net metering allows your solar panel to connect to your electrical grid, then share your electricity with the grid. With net metering, the utility company can track your energy production compared to your energy consumption. A growing number of jurisdictions now allow for net metering, which means you can earn money (or save money on your utility bills) by selling solar electricity to the grid.
Ultimately, solar energy production technology has improved enormously over the past decade. Originally, it was a costly and inefficient technology. Today, it’s quickly becoming the energy source of the future – and the technology has never been better.
