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Oct 29, 2020

How Do Solar Panels Work?

Solar power is one of the fastest growing sectors within the green energy industry. Improved technology, falling cost, environmental benefits and strong incentives have attracted many homeowners and even renters looking to go solar.

Installing solar panels or tapping into a solar farm is a win-win solution that we can all benefit from, but how does solar energy work? In this piece we’ll help you understand how solar panels generate energy from the sun.

How solar energy works: step by step

When we think of solar panels, we often think of them on a roof or a field as part of a collection of multiple solar panels, called a solar array. A single solar panel (or module), is made up of even smaller parts called solar cells, and these photovoltaic cells are where the solar power comes from. Simply put, solar panels work by absorbing the sun’s natural rays through their solar cells, generating direct current (DC) energy and that is then converted into alternating current (AC) electricity. Alternating current (AC) is what powers your home. Here are the main steps for how solar energy works:

  1. Solar cells absorb sunlight and convert it to DC energy – Each module contains a number of photovoltaic cells, which capture sunlight and produce DC energy. DC electricity cannot power your home alone. That’s where inverters come in.
  2. Solar inverters convert DC energy to AC electricity – An inverter is a critical piece of equipment in any PV system. Solar inverters convert DC energy into AC electricity that can be used to power your lights, appliances and electronics around your home.
  3. Solar electricity is used in your home – While your solar panels produce energy during the day, that electricity immediately runs through your meter and throughout your home to be used.
  4. Electricity produced by panels that is not used goes back to the utility grid – Any excess energy that is produced by your solar panels is fed back to your local utility grid.

How solar panels work: diagram

Distributed generation projects, like community solar, allows many individuals to access solar without installing solar panels on their property. These projects are bigger than what you see on your neighbor’s roof but the technology – and the power generated – is largely the same.

How solar cells work

There are numerous components that make up how a solar cell works; a metal plate on the back, two types of semiconductors, a metal grid, an antireflection coating, and glass. The first layer that sunlight encounters, is glass. The glass serves as the gatekeeper, blocking everything but sunlight from coming in. The next layer the sunlight hits is the antireflection coating, which is what makes solar panels have that blue hue. While it allows sunlight to go through, it also stops it from going back out.

But when does the generation of energy happen? When the semiconductors meet the sunlight. Semiconductors, or silicon, consists of two layers, n-type and p-type. This is where they establish an electric field similar to a magnetic field with positive and negative poles. As photons (sunlight particles) enter the two layers (n-type and p-type), they get trapped between the two and give up their energy to atoms within the n-type and p-type sandwich. The entering energy knocks electrons out of the lower, p-type layer, jumping across the barrier and back up to the n-type layer, and escape out into the circuit. Manufacturers also “dope” the silicon with other materials to help create that positive and negative electrical charge. A couple of other components and voila, we now have electrical current. Now comes the metal plate. These plates collect electrons and transfer them to wires. The wires then capture and feed DC electricity to a solar inverter that converts to AC electricity, putting your home on electric avenue!

How solar cells work: diagram

How solar panels work at night

Solar panels do not produce energy at night, which is why most rooftop solar arrays are generally grid-tied, meaning your home’s system is linked to your local utility company’s electrical grid. This allows you to have access to a power source at night. If your home is connected to a utility grid you will have a utility meter, typically placed on the siding or rear of your home. Solar panels are also connected to that meter. This will allow you to access and measure the production of your solar panels.

When your solar panels produce more power than your home uses, your meter will spin backwards. Why is this? Net metering is a solar incentive that allows your solar panels to feed any excess energy that you don’t use back to the utility gird in return for energy credits that can be applied to future utility bills. So, in months when there are more overcast days than there are sunny, you can use your energy credits to draw electricity from the grid to meet your household’s energy needs.

Just like net metering credits produced from a home with solar panels, individuals who are subscribed to a community solar farm can receive virtual net metering credits associated with their share of the farm, which offset their electricity charges. These credits then offset a subscriber’s electricity usage and are worth equal or near to what subscribers pay their utility company.

Aside from net metering, there are also home solar batteries. By coupling your solar panel system with a home solar battery, you are able to store electricity for use at night and when solar production is low. Solar batteries provide many benefits for solar panel system owners including electricity savings and power outage resilience.

Now that you understand how solar panels work and how solar energy works, you’re ready to help be part of the clean energy movement as an owner of a solar array or a subscriber to a solar farm. Interested in learning more about our community solar program? Visit our community solar page or call 800-965-5124 to learn more.

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