How Does Solar Energy Work?

CalendarJanuary 11, 2018

Did you know enough sunlight hits the earth in one hour to power it for a year?1 It’s true! Our modern-day world uses a lot of power and our Sun is up to the task. It’s pretty natural, then, that solar panels are becoming such a popular way for people to generate their own (clean!) electricity. But just how do solar panels work to get the energy from the Sun into your home? 

In a nutshell, here’s the flow:

  1. Photovoltaic cells in a solar panel convert sunlight into an electric current. 
  2. The current passes through an inverter to make it compatible with your home’s wiring and appliances (this is called an alternating current or AC).
  3. Alternating current is channeled into your home's wiring and is available for you to use as electricity!
  4. Any extra electricity is wired to the electrical grid (more on that later) or, if you have an energy storage system, some may be stored in a battery for later use.
  5. An energy meter measures how much electricity you use from or contribute to the grid.

how solar energy works

If you want more than an overview, stick with us for the details. If you need to go outside and marvel at the Sun’s vitality, we understand that too. 

1. Photovoltaic cells convert sunlight to an electric current

Each solar panel is made of photovoltaic, or PV, cells. PV cells convert photons (sunlight) into voltage and current (electricity). To geek-out at the science behind this, check out NASA’s explanation. A typical residential solar panel has 60 PV cells mounted under a piece of glass in an aluminum frame. Rooftop solar energy systems consist of multiple panels and are typically customized to produce the right amount of energy for the home.

To get the electricity from those solar panels to power a home, a couple of steps are needed after the PV cells do their job. First, the electrical current needs to match the type of electricity your home uses, then that current needs to get to your home’s wiring system.

2. An inverter converts DC to AC

There are two kinds of electrical current - Direct Current (DC) and Alternating Current (AC).  Solar panels generate DC, but our homes and appliances are made to use AC. An inverter is a device that uses electronic circuitry to convert DC to AC. Some solar panel setups have a single inverter (often called a “string” inverter) for the entire system and some have a microinverter attached behind each panel. Once the electrical current goes through the inverter, you have a current that can be used to power your home!

3. You use electricity - just like you do now!

The electric current is wired from the inverter into your home’s existing wiring. It works just like your electricity does now - you don’t have to change a thing.

Now that you know how powerful the Sun is, you may be wondering what happens if your solar panels produce more electricity than you need. To understand what happens next, you need to know something about the grid system.

4. Extra electricity goes back to the grid or charges a battery

The grid

Today, most homes in the United States use electricity provided by traditional power companies. These power companies generate electricity at a power plant, then use power lines to get the electricity from the plant into neighborhoods and homes. Rooftop solar panels also utilize the grid system, both to offload extra electricity and to give your home backup electricity as needed.

Being on the grid allows you to use exactly as much electricity as you need, when you need it, and send any excess back to the grid. Solar panels generate electricity when the Sun is up, but since most people use electricity at night, it’s important to have access to power from the grid any time. 

With solar panels, you are essentially producing electricity at home instead of buying it from a remote power plant, so it’s greener and typically cheaper, but you still get the delivery benefits of the grid system. If you’d rather have some more energy independence, however, you may be able to install a battery.

Energy storage

Batteries are available for some rooftop solar setups. Including a battery allows you to store the extra energy you generate when the Sun is shining for use later (like at night, on cloudy days, or in the event of a power outage). Because many energy companies have a net metering agreement (which we’ll explain next), an energy storage option may save you money. 

5. A net energy meter measures the electricity you use from, or add to, the grid

For this last part, you’ll need to know what a net metering agreement is. Depending on where you live, your utility company may provide energy credits for excess energy that you sent to the grid that roll over and some will even cut you a check at the end of the year for the surplus power. Then, at times when you need to use electricity from the grid, you can use that credit towards your monthly energy bill. This is called net metering.

Net meters are devices used at your home to measure the electricity going to and from the grid. These meters are like the electric meter you probably have now, but they measure power going in two directions instead of one. You can get more specifics on net metering here.

And there you have it! Now that you know how solar works, you’ll know exactly what’s happening with those shiny panels when you see them and can even use your knowledge as your next party trick when solar comes up in conversation.

If you want to take your knowledge of solar a step further, read about how to know if a home qualifies for solar or contact a solar provider today.  

Endnotes
1.  https://www.nrel.gov/workingwithus/re-solar.html

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