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How do solar panels work?

Learn how solar panels convert sunlight into usable electricity

by Kathryn Parkman ConsumerAffairs Research Team
roof of suburban home with solar panels

What are solar panels?

Put simply, solar panels are a collection of solar cells made up of smaller photovoltaic (PV) cells. Each PV cell is approximately six inches long by six inches wide, squarish and looks like a small reflective window. The cells are arranged in a grid, which makes up the panels. The PV cells are encased by a semiconducting material. In residential solar panels, this material is most typically crystalline silicon (solar cells on space satellites utilize thin-film technologies with cadmium telluride and amorphous silicon). Either way, it’s the grouping of these cells into a grid that makes up a solar panel that can then absorb sunlight and convert it into energy.

How solar panels work

A solar panel works by absorbing sunlight through solar cells, which creates a direct current. The direct current then travels from panels through an inverter, which converts the energy into usable electricity as it reaches to the breaker panel of your home. It’s almost like having your own personal power plant on your roof with an endless supply of clean energy.

  1. Solar panels absorb energy from sunlight
    The sun is like a natural nuclear reactor, always releasing energy. The energy released by the sun, called photons, hits the photovoltaic cells, which creates an electrical field and produces a direct current (DC).
  2. Inverters convert direct current into usable electricity
    Typically solar panel systems have a single inverter for the entire system or a microinverter connected to every panel. Either way, the purpose of the inverter is to convert direct currents (DC) into alternative currents (AC), which is what makes electricity usable inside your home.
  3. Electricity from solar panels is used in your home
    Electricity powers your home and appliances just like normal. If for whatever reason the residential solar panels you installed didn’t produce enough power to meet your electricity needs, you’ll be able to source electricity from the grid automatically.
  4. Leftover electricity goes back on the grid
    Sometimes solar panels will produce more power that you and your family need. When this happens, electricity will go back onto the grid. This is why you’ll still want to be attached to your traditional power grid.
  5. Electricity is measured by the net meter
    Depending on your net metering agreement, your local utility company might give you energy credits for surplus power your solar panels send back to the grid. Some utility companies will even reimburse you for your power production credits.

Solar panel questions

What are solar panels made of?

A solar panel is made up of many solar cells, which are made up of layers of oppositely charged semi-conductive materials.  Crystalline silicon is the semiconducting material used in solar electric technology to produce solar cells. These solar cells are then built into monocrystalline or polycrystalline solar panels. Photovoltaic (PV) solar panels are made up a collection of silicon crystal solar cells that function as semiconductors.

Like batteries, each cell has a positive layer and a negative layer, which together create an electric field. Just the solar panel’s cells are not enough to power your home though. A solar panel’s cells require metal casing and wiring to allow electrons to become useful power. Recent advancements in new synthetic materials continue to make solar panels more cost-efficient and reliable sources of power.  

How are solar panels made?

The main component that makes solar panels work is silicon. Silicon is extracted from quarries, heated and then transferred into large barrels to be used in many products. Solar panels are made with two large, thinly sliced sheets of silicon.

Because silicon is not a good natural conductor, a process called “doping” intentionally adds impurities: usually baron, which bonds with silicon to create a positive charge, and phosphorus with combines to create a negative charge.

The panels are then treated with anti-reflective coating that is painted on and baked into place. This minimizes wasted energy. One of the two panels is dyed blue so the panel can absorb more light, and therefore create even more energy. High-tech computers then spray a layer of semi-liquid metal onto the panels, which helps get the energy from the panel to your plugs and into the appliances you need to power.

How long do solar panels last?

Most residential solar panels come with a warranty of 25 years. Most solar energy companies predict a loss of efficiency of .8% every year, so after 25 years your solar panel should meet an 80% efficiency standard. In general, crystalline panels last longer than thin-film panels. Some crystalline panels have been known to function at high efficiency for over 40 years.

How do solar panels produce electricity?

A solar cell gathers light from the sun and generates electricity. Sunlight hits the top surface of the photovoltaic panels in waves, where the sun’s electromagnetic radiation is absorbed into the solar cells. A single solar cell can create enough electricity to run a calculator, and a collection of these cells in panels can produce enough electricity to power a house. As long as the sun is shining, the panels are absorbing the sun’s energy and converting into electricity.

How do solar panels work at night?

Solar panels require sunlight to generate electrical energy, but there are two ways to access electrical energy through your solar panels at any time. Solar panels can work at night if your solar panel system includes energy storage capability. With this function, excess energy that’s collected during the day will be stored for later use, so you can still run on solar power even when it’s dark.

Another option is net metering. With net metering, any excess solar power is fed back into your traditional power grid. Your utility company can then credit you for generating electricity and maintain your connection after solar panels are installed, so you’ll have access to power 24/7, even on cloudy days when solar panels generate electricity less efficiently.

Do solar panels save money?

Yes. To figure out how much money solar panels can save you, you’ll need to consider your average monthly utility bill and the total cost of equipping your home to run on solar energy. EnergySave projected the average 20-year savings for a home in Washington (a state with above-average cloud cover) would be around $10,000, while savings for homes in California would closer to $30,000.

LabelCompany nameLogoContactSummary
Best solar company Visit website
  • Type of solar panel: Monocrystalline silicon PERC
  • Efficiency rate: 15–22%
  • Warranty: 25 years
LabelCompany nameLogoContactSummary
Runner-up Visit website
  • Type of solar panel: Monocrystalline
  • Efficiency rate: 22%
  • Warranty: 25 years
LabelCompany nameLogoContactSummary
Runner-up
  • Type of solar panel: Monocrystalline
  • Efficiency rate: 18.8%
  • Warranty: 25 years

Bottom line

The entire globe’s energy consumption could be powered using just the amount of sunlight that hit the earth's surface in the last 90 minutes. The solar energy market is constantly evolving and changing to meet the growing demands for renewable energy and to harness the potential the sun provides on a daily basis. Using a solar energy system on your home is a cost-effective and sustainable to power your home.

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by Kathryn Parkman ConsumerAffairs Research Team

As a member of the ConsumerAffairs Research Team, Kathryn Parkman believes everyone deserves easy access to accurate and comprehensive information on products and businesses before they make a purchase, which is why she spends hours researching companies and industries for ConsumerAffairs. She believes conscious consumption is everyone's responsibility and that all content deserves integrity.