How Do Solar Panels Work?
How Solar Works Step-by-Step
It’s really as easy as 1-2-3. You generate free electricity from the sun that powers your home and any solar power you don’t use gets pushed back into the utility grid for a full value credit.
Sunlight to DC Electricity
Solar panels are mounted on your roof and convert sunlight into DC electricity that flows to an inverter.
Converting DC to AC
Inverters convert the direct current (DC) power into alternating (AC) power that your home can use.
Meter Spins Backwards
You’ll still have utility power when you need it. Any excess electricity will be delivered to the grid for a credit.
Considered a promising energy source for decades, photovoltaic or solar panels can be found on everything from rooftops and roadside signs to stadiums and spacecrafts. Solar energy works by capturing energy from the sun and converting it into electricity for homes and businesses.
The sun is basically a nuclear reactor. It releases tiny bits of energy called photons. These photons then travel 93 million miles from the sun to Earth in approximately 8.5 minutes. The sun emits enough photons in one hour to theoretically generate enough power to meet global energy requirements for an entire year. That is a staggering statistic.
Currently, photovoltaic or solar power provides only five-tenths of one percent of the power used in the United States. But as solar technology improves and the cost of switching to solar drops, our ability to capture and use the sun’s abundant energy is increasing.
In fact, the International Energy Agency report Renewables 2017 showed that solar power has become the fastest growing energy source – accounting for approximately two-thirds of net new capacity globally. This was the first time solar energy capacity surpassed any other fuel as a source of power. In the coming years, we all will be using solar power, whether we realize it or not. This also means that the time is right to invest in solar power for your home.
How Solar Panels Work
Solar panels work by letting photons released by the sun knock electrons free from atoms, and thus generate a flow of electricity. Solar panels are composed of many smaller photovoltaic cells linked together. The more panels you deploy, the more energy you generate.
Each photovoltaic cell is made up of two slices of semi-conducting material, usually silicon. The cells have a positive and negative layer that together create an electric field, much like a magnetic field or battery that need both a positive and negative charge to work. To get this electric field, we add other materials to each “slice,” giving them either a positive or negative electrical charge.
Phosphorus is seeded into the top layer of silicon, which adds the extra electrons needed to get a negative charge. The bottom layer is treated with boron, which subtracts electrons, giving it a positive charge. This creates an electric field at the junction of these two silicon layers. When a photon of sunlight hits the photovoltaic cell, an electron is knocked free. The electric field pushes the electron out of the silicon junction, creating energy.
How Does Solar Energy Work?
Once the photovoltaic cells in the solar panel create energy from the sun, there are a few more steps required to make it usable energy. PV or solar panels generate direct current (DC) electricity. With DC electricity, the electrons flow around a circuit in one direction. Think about how a battery powers a light bulb. The electrons travel from the negative side of the battery, through the lamp, and into the positive side of the battery. With alternating current (AC) electricity, electrons are pushed and pulled. They travel back and forth, periodically reversing direction, in much the same way a cylinder in a car’s engine does.
Generators create energy when a wire coil is spun next to the magnet. Many different types of energy sources can be used for this process, including diesel or gas fuel, coal, nuclear energy, hydroelectricity, wind and solar.
The U.S. power grid uses AC current. AC current was selected mainly because it is cheaper to transmit over long distances. However, solar panels generate DC electricity. This means we need a way to get DC electricity into the AC grid. For this, we use a solar inverter.
To simplify all this, here is step-by-step guide to how solar energy works:
Step 1: Sunlight reaches the solar panels, and they start working to generate an electric current (DC).
Step 2: The electric current (DC) starts to flow into the inverter, which is responsible for converting DC electricity into AC, which is the most commonly used form of electricity.
Step 3: The AC electricity moves from the inverter to the breaker box. Then, the current moves into any appliance in the home/building using electricity.
Step 4: Unused electricity or excess electricity moves back to the utility meter and into the grid. You are credited for that on your power bill. When your home needs more energy than what is produced by your solar panels, electricity will be drawn from the grid.
What Is a Solar Inverter?
A solar inverter uses the DC electricity collected in the solar array to create AC electricity that can be used in your home. Think of inverters as the brain of the solar panel system. Although converting DC to AC electricity is an important role, inverters also provide ground fault protection and system statistics. This includes voltage and current on the AC and DC circuits, maximum power point tracking, and energy production.
In the beginning of the solar power industry, there were central solar inverters, and since their introduction, they have pretty much dominated the industry. However, the introduction of microinverters created one of the biggest shifts in technology in the solar energy industry. Microinverters optimize for each solar panel while central inverters optimize for the entire system. By optimizing for each panel, every panel performs at its maximum potential. In the long run, this “smart” technology makes your entire solar panel system more efficient.
When a central inverter controls the system, one problem panel can affect the efficiency of the entire system. It could be that the panel is in the shade for a time or has gotten dirty. Whatever the reason, when a panel is not working at maximum capacity it can drag down the performance of the solar array as a whole. Microinverters or power optimizers allow your solar panels to communicate with each other and deliver as much power as possible under all conditions. It also means that if one solar panel is having an issue, the rest of the panels still perform at maximum efficiency.
How Do Solar Panels Work on Your Home?
That’s a lot of technical information about how solar panels work, so let’s look at how a solar panel array would work on your home. First, sunlight in the form of photons hit the solar panels on your roof or ground mount. The panels convert the energy in the photons to DC current, which then flows to an inverter and is converted from DC electricity to AC electricity. This electricity is then used to power your home. It’s simple and clean, and it's becoming more efficient and affordable.
However, what if you are not home? You may not be using the electricity your solar panels generate. What happens at night, when there is no sunlight and your system is not generating power? Not to worry, you still can use the energy your system has created. This is where net metering comes in.
A typical grid-tied solar panel array produces more energy that you can use during peak sunlight hours. That excess energy goes back into the grid and is used by someone else. You are credited for the excess energy your system produces. When needed, you can draw on that credit to get power from the grid during the night. A two-way meter keeps track of the energy sent to the grid along with the energy received from it.
How Do Solar Panels Work with Grid Connection?
Although most people understand that solar panels help them generate their own power so that they don’t have to depend solely on the power company, there is still confusion about the role the grid plays in home solar energy systems.
Homes that are connected to the electrical grid have a utility meter that measures how much electricity you use. If you have net metering, when your solar power system is overproducing, you send the excess power to the grid in exchange for credits on your bill. Then, during hours of low production, such as the nighttime, you use your credits to meet your home’s energy needs. Net metering gives you a way to store your energy and use it when you need it. This significantly improves the economics of solar power.