What is solar power?

The sun doesn’t just provide warmth and light – it’s also a source of energy.

Solar energy (or solar power) is the energy we generate from sunlight. Through a process known as the photovoltaic effect, we can convert energy from the sun’s rays into electricity that can power our TVs, refrigerators, lights and other appliances.

(The photovoltaic effect is what makes solar possible. Read more about how it works on Wikipedia.)

To generate solar energy for your home or office, you need a solar power system. We’ll go over the parts of that system later in this guide, but first let’s talk about the most recognizable part of the system: solar panels.

What are solar panels made of and how do they work?

Solar cells are made primarily from silicon, a chemical element with conductive properties. Exposure to light changes silicon’s electrical characteristics, which generates an electric current.

A cell is a small square of silicon (about 6” x 6”) with electrical contact plates on the face. Solar panels are made by laying out a grid of these cells on a protective backsheet and covering them with glass on the front.

Panels come in 60 and 72-cell configurations (plus a few others which are much less common). If you want to know when you might choose one over the other, read our breakdown of 60 vs 72 cell solar panels.

It takes multiple panels to provide power to a typical home or office. A collection of panels in your system is called an array. Panels wired into the same inverter are known collectively as a string of panels. (Inverters have a maximum string size – an upper limit to the number of panels they can support.)

For example, you may have a system with two inverters supporting two strings of 10 panels each, which comes together to make a 20-panel array.

How do solar panels work and generate electricity?

A standard solar panel (also known as a solar module) consists of a layer of silicon cells, a metal frame, a glass casing and various wiring to allow current to flow from the silicon cells. Silicon (atomic #14 on the periodic table) is a nonmetal with conductive properties that allow it to absorb and convert sunlight into electricity. When light interacts with a silicon cell, it causes electrons to be set into motion, which initiates a flow of electric current. This is known as the “photovoltaic effect,” and it describes the general functionality of solar panel technology.

The general photovoltaic process, as described above, works through the following steps:

1. The silicon photovoltaic solar cell absorbs solar radiation
2. When the sun’s rays interact with the silicon cell, electrons begin to move
3. Moving electrons creates a flow of electric current, captured by nodes and wiring in the panel
4. Wires feed this direct current (DC) electricity to a solar inverter to be converted to alternating current (AC) electricity

Other important solar panel parts

In addition to silicon solar cells, a typical solar module includes a glass casing that offers durability and protection for the silicon PV cells. Under the glass exterior, the panel has a layer for insulation and a protective back sheet, which protects against heat dissipation and humidity inside the panel. The insulation is important because increases in temperature will lead to a decrease in efficiency, resulting in a lower solar panel performance.

Solar panels have an anti-reflective coating that increases sunlight absorption and allows the silicon cells to receive maximum sunlight exposure.

How do solar panels work for your home?

Solar panels work by absorbing sunlight with photovoltaic cells, generating direct current (DC) energy and then converting it to usable alternating current (AC) energy with the help of inverter technology. AC energy then flows through the home’s electrical panel and is distributed accordingly. Here are the main steps for how solar panels work for your home:

1. Solar panels absorb the sun’s energy and convert it to DC electricity
2. The solar inverter converts DC electricity from your solar modules to AC electricity, which is used by most home appliances
3. Electricity flows through your home, powering electronic devices
4. Excess electricity produced by solar panels is fed to the electric grid

How does grid connection work with solar panels?

Though electricity generation with solar panels may make sense to most people, there’s still a lot of general confusion about how the grid factors into the home solar process. Any home that is connected to the electrical grid will have something called a utility meter that your energy provider uses to measure and supply power to your home. When you install solar panels on your roof or on a ground mount on your property, they are eventually connected to your home’s utility meter. The production of your solar system can actually be accessed and measured by this meter.

Most homeowners in the U.S. have access to net metering, a major solar incentive that significantly improves the economics of solar. If you have net metering, you can send power to the grid when your solar system is overproducing (like during the day in sunny summer months) in exchange for credits on your electric bill. Then, during hours of low electricity production (such as nighttime or overcast days), you can use your credits to draw extra energy from the grid and meet your household electricity demand. In a sense, net metering offers a free storage solution to property owners who go solar, making solar an all-in-one energy solution.

Considering that the most common aversion that people have to going solar is the issue of what to do at night or on days with bad weather, a free storage solution as efficient as net metering is a game changer in terms of solar adoption. These types of incentives, plus the fact that the cost of solar has dropped by almost 70 percent in the past decade, can explain why the solar industry is growing at an exponential rate in the United States.

How homeowners can guarantee major solar savings?

For those starting to consider a solar panel array for their home, there are a number of factors to consider including financing, equipment, installer selection, and warranties. In addition to all of these topics is the question of how to make sure you can get a good deal and generate strong energy savings in the long run. For people new to the solar shopping process, we have some key points of advice that will guarantee you get the best deal on your solar module system.