How Grid-Tied Solar Inverters Differ from Off-Grid Inverters

When purchasing a solar inverter for your grid-tied solar system, there are many factors to consider. But perhaps the most important thing to bear in mind is that you purchase a solar inverter designed for a grid-tied system. While you may think that a solar inverter is a solar inverter, and there aren’t any major differences between the 2, that’s not true. Keep reading to learn the main differences between off-grid and grid-tied solar inverters.

Grid-tied solar inverters are actually designed to communicate and synchronize with the city power grid. The inverter’s output voltage and frequency are synchronized to the main power supply. Essentially, it uses the grid as a reference for voltage, frequency, and phase. This makes it possible for a grid-tied inverter to feed energy back into the power grid—something an off-grid inverter can never do.

Off-grid inverters are designed to work alone and are incapable of synchronizing with a power grid. They are meant to replace a power grid, not work in conjunction with it. They must generate their own voltage and frequency, while also monitoring the AC load to ensure it only makes as much AC power as you currently need, regardless of how much DC power the array is currently creating.

Because a grid-tied inverter can communicate with the city grid, they have the processing intelligence to switch between power sources to supply your home with constant energy, regardless of whether or not your solar array is currently producing electricity. When there is solar energy available, the inverter will deliver that power to your home. When the energy production is insufficient, it automatically switches back to the power grid.

While off-grid inverters may be able to alternate between supplying fresh solar energy and the energy stored in your battery bank, it cannot access a power grid. Even if you live in an area where a grid is available, if you have an off-grid inverter, you won’t be able to tap into that energy source.

A grid-tied solar inverter is also prone to the power outages that the connected grid might experience. Even if your array is currently generating energy, if the grid experiences a power outage, your inverter will also shut down. This is a safety measure to ensure that electricity is not flowing from your array into the grid while workers are trying to fix the outage.

An off-grid inverter is not prone to widespread outages. However, you are limited to the energy your array can supply and your battery bank can store; once this energy is depleted, you’ll need to either rely on a generator or go without electricity until the solar panels begin producing again.

If you have a grid-tied solar system, it’s important that you purchase grid-tied solar inverters in order to properly utilize both your array and the city power grid.