How do solar panels work?

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

The science of generating electricity with solar panels boils down to this photovoltaic effect. It was first discovered in 1839 by Edmond Becquerel and can be thought of as a property of specific materials (known as semiconductors) that allows them to create an electric current when they are exposed to sunlight.

The photovoltaic process works through the following broad 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, creating a flow of electric current
3. Wires capture and feed this direct current (DC) electricity to a solar inverter to be converted to alternating current (AC) electricity

A brief history of solar power

In 1954, Bell Labs developed the first silicon photovoltaic cell. Although solar energy had previously been captured and converted into usable energy through various methods, only after 1954 did solar power begin to become a viable source of electricity to power devices over extended periods of time. The first solar cells converted solar radiation to electricity at an efficiency of 4 percent — for reference, many widely available solar panels today can convert sunlight to solar power at above 20 percent efficiency, a number constantly on the rise. Although solar energy adoption was slow at first, a number of state and federal incentives and policies contributed to driving down the cost of solar far enough to become more widely adopted.

The cost of solar energy

Concurrent with an increase in solar efficiency, the cost of solar panels has fallen substantially. In the last decade alone, the cost of a solar panel installation fell over 70 percent, and many industry experts predict that prices will continue to fall in the years to come.

Additionally, depending upon where you live, several rebates or incentives for solar power may contribute towards lowering the cost of solar energy even further. Nationwide, the federal Investment Tax Credit (ITC) is one of the primary incentives available to anyone interested in solar energy, as it allows you to deduct 30 percent of the cost of installing a solar array system from your federal taxes. This incentive won't last forever: in 2033, the federal ITC steps down to 26% and it will go away completely for residential solar installations in 2035. Many states and utilities offer further incentives (such as net metering) in addition to the federal ITC, dropping the cost of solar power even further.

Interested in seeing what solar will cost you? Try our solar calculator for a quick estimate.

Solar energy is a renewable power source

Solar energy is a clean, inexpensive, renewable power source that is harnessable nearly everywhere in the world — any point where sunlight hits the surface of the earth is a potential location to generate solar power. And since solar energy comes from the sun, it represents a limitless source of power. Renewable energy technologies generate electricity from resources that are infinite.

Compare producing electricity with renewable resources to fossil fuels: it took hundreds of thousands of years for oil, gas and coal to form. So, every time one of those resources is burned to create electricity (and emissions!), that finite resource is moved marginally closer to depletion. Using a renewable resource — such as wind, solar and hydropower — to generate electricity does not deplete that resource. There will always be consistent sunlight shining on Earth's surface, and after turning sunlight into electricity, there is still an infinite amount of sunlight to turn into electricity in the future. That is what makes solar power, by nature, renewable energy.

While the current electricity mix in the United States is still made up largely of fossil fuels like oil and gas, renewable energy sources like solar are steadily becoming a larger part of the country's energy profile as the cost becomes more competitive.

Should you go solar?

When it comes to installing solar panels and switching to a more eco-friendly energy source, there’s not a one-size-fits-all approach. There are several questions you should ask to help determine if your home or business is a good candidate for solar:

• How much electricity do you consume and how much does electricity cost in your area? The more electricity you use, and the more you pay for it, the more you’ll save by going solar.
• Do you own your home? If you live in a multi-family home or rent the property, it will be much more difficult to install solar than if you own a single-family home.
• Is your roof good for solar? The ideal roof for solar would be one that’s pretty spacious, is in good condition, isn’t too complex, is southern-facing, and receives plenty of direct sunlight. If not, you should consider if you have land space for a ground-mounted system.
• Are there local, reputable solar companies in your area that can perform the installation? If you don’t live in an area with multiple installers competing for your business, you may end up paying a premium.
• What incentives are available where you live? Local and state incentives could end up saving you thousands of dollars on your solar energy system, significantly shortening your payback period.

If some of these characteristics aren’t aligned with your situation but you’re still interested in going solar, read our article about if solar is right for you for more information on whether you’re a good fit.