Solar Islanding and Anti-Islanding: What You Need to Know

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Most people turn to solar power for energy independence from the utility grid. Having solar panels doesn’t prevent blackouts or power outages. Solar panels are usually grid-tied and automatically turn themselves off during such an event. This prevents “solar islanding.” To avoid all this, you need a solar energy island capable of generating power even in the harshest times. 

Solar Islanding

In solar islanding, a home’s solar power system can produce electricity even if the grid isn’t functioning. Most consider this remarkable since your home can produce power when no one else can. However, this can prove dangerous for utility workers actively fixing the grid when they produce electricity, which goes into the grid. If the grid is “live,” these workers could be seriously injured. Several things can go wrong if solar islanding isn’t avoided:

  • The local grid stops working.
  • Your home, being grid-tied, still generates electricity.
  • Excess electricity from your home goes to the grid.
  • The workers start fixing the grid.
  • Exposure to live wire could cause shocks, severe burns, or, worst case, death to a worker.

Fortunately, you can practice solar islanding without endangering anyone’s life.

Off-the-Grid vs. Grid-Tied Solar 

Most homes are grid-tied, even with solar panels. Often, solar panels do not match your home’s daily energy needs. The grid steps in to fulfill that energy requirement. If the grid shuts down for any reason, your solar panels automatically shut down as a safety feature to protect the people working on fixing the grid.

In solar islanding, you’re generating your power without any reliance on the grid. You don’t even have a connection to the grid in the first place. So in the event of any harsh weather, your solar power system will keep operating.

Most people confuse going off the grid with going solar. However, that isn’t true. You can still require energy from the grid if you’re going solar. But with going off the grid, you completely rely on solar panels and your battery backup for power.

Solar Anti-Islanding

This is a safety feature that comes with solar power systems that are connected to the grid. This disconnects and shuts down those solar power systems during a power outage. If an inverter has anti-islanding protection, the detection system determines the frequency and voltage when the grid is down. It then avoids feeding power back to the grid to protect utility workers.

A solar inverter with anti-islanding is important because it:

Prevents Inverter Damage:

Solar islanding can damage your inverters and render them inoperable. However, anti-islanding avoids that by not letting your inverters overload. This saves you money since you prevent costly damage.

Keeps The Grid Safe:

If the grid isn’t functioning and your solar power system sends voltage back to the grid, it could damage grid hardware. Anti-islanding protects that by shutting down your solar power system if the grid goes down.

Ensures Worker Safety:

Workers fix the grid, assuming no voltage will flow since it’s shut down. However, if some house is still producing excess electricity from their solar panels, it can travel to the grid and injure or kill that worker. Solar anti-islanding protects these workers from shocks, burns, and death.

The UL Standard 1741 requires every grid-tied PV system to have a built-in anti-islanding solar inverter, so you don’t need to worry about any worker getting shocked by the electricity you produce.


A solar inverter converts the DC electricity from solar panels into AC power for your home. When your home with solar panels is connected to the grid, this inverter becomes a grid-tie inverter. It will allow an uninterrupted power supply to your home regardless of how much or how little energy your solar panels generate.

Grid-tie inverters can synchronize power delivery with the grid and know the correct time to send power to the grid. This is a rapid and efficient process with the benefit of disconnecting from the grid when anti-islanding is required.

Solar Islanding And Battery Storage

You just need adequate battery storage and a compatible solar inverter for a safe islanding experience. A solar islanding system allows the inverter to manage a complicated yet important role during a power outage:

  • The inverter will disconnect your home from the grid, so anti-islanding is possible.
  • A transfer switch connects your home to the solar power system in island mode.
  • Any energy requirements are filled by the power drawn from your backup battery.
  • Then your panels generate electricity to power your home and recharge the batteries.

Solar energy islanding removes any risk of sending electricity to the grid during a power outage. This is only possible if you have inverters and large batteries operating in solar islanding mode. This system is more expensive than a grid-tied but provides more peace and privacy. So, ultimately it’s up to you to decide if that peace is worth it to you or not.

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