How Solar Photovoltaic Systems Produce Electricity

Today, most people will tell you that they have some sort of understanding of how solar panels work. After all, the concept is pretty simple, right? Panels installed on a roof absorb the sun’s energy and use it to power a person’s home or business.  

The thing is, how does this happen? How can we get power from sunlight, and not only that but how does that power get converted into something that works with the electrical systems and appliances in our homes? Most solar professionals will tell you that while homeowners understand the general concept of solar PV, they are often less likely to understand the specifics.  

Today, we will explain the exact process by which a solar photovoltaic (PV) system produces electricity, take a closer look at the components of a solar PV system, and explain what happens to any of the surplus energy generated by a solar system. 

What is a Solar Photovoltaic System? 

A solar photovoltaic system, commonly referred to as a solar PV system, combines everything necessary for sunlight to be gathered and converted into usable power. This includes the solar panels themselves, the materials used to anchor the panels to the roof, and the inverter used to convert your electricity, amongst other things.  

Just buying and installing PV panels won’t be enough to convert sunlight into electrical power. More components are at play when generating free, renewable energy for a home. Before we get to how solar photovoltaic systems produce electricity, it’s essential to understand what role each component of a PV system plays in generating power.  

Solar PV System Components 

• Solar Cells: Typically made of silicon, solar cells are the main component of a solar panel. These are what produce energy through what’s called the photovoltaic effect. The most common varieties of solar cells are monocrystalline (one single wafer of silicon) and polycrystalline (combined shards/pieces of silicon). 
• Solar Panels/Solar Modules: Solar panels house a group of solar photovoltaic cells and can be installed on a roof or the ground in a grouping called a solar array.  
• Inverters: A solar inverter is the component of a PV system that converts the DC electricity generated by the solar cells into the AC electricity accepted by a home. Without an inverter, a PV array will not be able to power anything.  
• Wiring: Wiring encompasses every cable necessary to connect each solar system component. Wires are used to connect PV cells into arrays, the array to the inverter and the disconnects, and the system to the grid and home.  
• Racking: Racks are used to fix solar panels on roofs or the ground.  
• AC/DC Disconnects: Required by most building codes, AC and DC disconnects are switches that can quickly stop the flow of electricity from solar arrays to both the home and the grid in the event of a fire or other emergencies, as well as for maintenance. You can think of solar disconnects as a kill switch for your solar system.  
• Solar Trackers (optional): Solar trackers can be installed as a component of a ground-mounted system to enable the panels to “follow” the sun, allowing them to always tilt at the optimal angle to generate the most solar power possible.  

How does Sunlight Become Usable Energy? 

Unlike electricity generated from other sources like natural gas, coal, or nuclear energy, solar cells don’t rely on chemical reactions to produce power. Instead, they take advantage of the photovoltaic effect in which light (photons) hits certain crystals, such as the silicon you’ll see in solar panels, and agitates electrons, knocking them into an aluminum layer so that they can flow in the form of an electric current.  

Solar panels have two layers of silicon, one that is positively charged, called the p-type, and one that is negatively charged, the n-type. The n-type semiconductor easily gives away electrons, while the p-type semiconductor is capable of receiving extra ones and letting the power flow freely.  

From the panel, the electric current will flow through the system’s wiring to the solar inverter, which will convert the power from direct current (DC) to alternating current (AC). Solar inverters can be installed on each string of solar panels as a singular central inverter or come in the form of microinverters attached to each PV module itself.   

Once the power hits the inverter, the electricity is ready to feed into the home and power anything from a toaster to an HVAC system.  

What Happens When PV Panels Generate More or Less Solar Energy than Needed? 

Unlike other forms of power, the sun isn’t always available when you need it. Solar panels will still generate electricity when it’s cloudy or snowy out, but what happens when the sun sets every night? Here are some common solutions for when your solar photovoltaic system generates more or less electricity than you need.