Most residential solar systems in Alberta are grid-tied, meaning they are connected directly to the utility power grid. This setup is popular because it allows homeowners to offset their electricity use and sell excess energy back to the grid through a process called net metering.
However, one of the most common misconceptions I encounter when talking with homeowners is the idea that their solar system will continue to power their home during a grid outage. Unfortunately, that is not the case. The reason comes down to safety.
Why Solar Shuts Off During a Power Outage
When the grid goes down, utility crews are often dispatched to repair damaged power lines. If a solar system continues to feed electricity into those lines, it can create a dangerous situation known as islanding.
Islanding happens when a solar-powered home or neighborhood continues to energize the grid even though it is officially off. To protect line workers from the risk of electrocution, solar systems are designed to detect grid failures and shut off automatically during an outage.
The Role of the Inverter
The inverter is the component that converts the DC power from your solar panels into AC power for your home. Most inverters used in Alberta are grid-following, meaning they rely on the grid’s frequency and voltage to operate.
- When the grid shuts down, those signals disappear.
- Without the grid signals, the inverter automatically shuts off and your solar system stops supplying power.
- Once utility power is restored, the inverter senses that the grid is back online and resumes normal operation automatically.
How to Keep Your Home Powered During Outages
If keeping your home powered during outages is important, a standard grid-tied solar system alone will not suffice. There are a few options to consider:
1. Battery Backup Systems
Battery systems like the Tesla Powerwall or Enphase IQ Battery can store solar energy for use when the grid is down. These systems allow your solar panels to continue powering your home independently of the utility grid.
2. Hybrid Inverters with Transfer Switches
Some hybrid inverters include built-in transfer switches that can power essential loads from your solar system during an outage. These systems are more complex and costly than a standard grid-tied setup but provide added resilience for critical appliances.
Planning for Backup Power
If backup power is a priority for your home, whether due to frequent outages or for peace of mind, it is important to plan for it from the start. Pairing your solar system with batteries or a hybrid inverter can give your home energy independence and added resilience during grid failures.
For homeowners looking to better understand the limits and possibilities of grid-tied solar, I often recommend checking out Enphase Energy’s explainer video, which goes into detail on this topic.
Final Thoughts
While a standard grid-tied solar system will not keep your lights on during a power outage, there are solutions available. Adding batteries or hybrid inverters allows Alberta homeowners to get the most out of their solar investment while maintaining backup power for critical needs.
If you want to explore your options for solar with battery backup or hybrid systems in Alberta, feel free to connect with me and I can help design the right system for your home.