With solar panel installations on the rise, it’s important to understand the difference between a battery storage system and a grid-tied system. A grid-tied solar system sounds complicated, but it’s actually pretty simple when you look at each piece of the system by itself.

The first step of the solar power process starts with the solar panel. Well, actually, it starts 92 million miles away at the Sun, but let’s skip ahead a little bit. Sunlight hits the surface of the solar panel, which is made up of a number of small photovoltaic cells. These cells use a semiconductor material, typically silicon, that reacts with the light energy on an atomic scale to produce an electric current.

Each photovoltaic cell is designed like a sandwich, with two layers of silicon, each of which has been treated with different materials, like phosphorus and boron, to give them a positive or negative charge and create an electric field between them. As sunlight hits the panel, photons that pass through the cell can knock an electron free of this electric field, which is then captured by conductive plates and transferred to wires.

The electricity generated by the solar panels is direct current, or DC, meaning the electric current only flows in one direction. To be used in a household or on the power grid, it has to be alternating current, or AC. Wires from the solar panel lead to an inverter that converts DC to AC. At this point, the electricity is ready to power your home and appliances.

Depending on your usage requirements, there may be days when your solar panels are generating more electricity than your home needs. In a grid-tied solar system, this surplus of electricity is sold to the electric grid, earning you credits from the utility company that you can use in the future when the sun isn’t shining as strongly. A grid-tied system connects your home to the grid through your power meter, where your electricity usage and production can be measured by your utility company.

A grid-tied solar system will not function during a power outage. If the grid is offline, your solar inverter will go offline automatically. Preventing your solar panels from outputting electricity to the grid protects the utility workers who are working on repairing the lines. A battery backup would allow you to continue using power during an outage. Some homeowners opt to install a natural gas or propane generator to produce electricity during a power outage, but these systems are costly.

Grid-tied solar systems are getting more and more economical due to tax credits, rebates, and advances in technology that are lowering the overall costs of solar power worldwide. Total costs of a grid-tied system will depend on several factors, including the size and mounting of your panels, and whether or not you install a battery backup system. In the tri-state (PA, DE, NJ) area, contact TerraSol Energies to find out if a grid-tied solar system is right for you and your home.