Do Grid-Tied Solar Panel Systems Work In a Blackout?

Grid-tied solar panel systems can help offset your electricity costs by supplementing the power you pay for from your utility provider.

In some locations, you can sell excess electricity your system generates to your power company in exchange for credits that reduce your energy bills.

At one point, grid-connected solar panel systems were the only viable option for most homeowners seeking to benefit from renewable energy.

However, times have changed.

If you’re like most people, an off-grid or hybrid solar panel system will offer a better return on investment and home energy security.

Grid-tied solar panel systems don’t work during power outages. 

An Overview of Grid-Tied Solar Panel Systems

Grid-connected renewable energy systems — like residential solar panel arrays and small wind turbines — are designed to supplement utility grid electricity, not replace it.

Such systems are connected directly to the utility grid, allowing for the flow of electricity in both directions.

All clean, renewable energy sources are intermittent — meaning their output varies depending on weather conditions and the time of day.

Wind turbines don’t generate electricity on still days.

Solar panels don’t work at night. 

There are two solutions to the intermittency of solar energy for home systems.

One is to integrate solar battery storage, which enables you to store the electricity your solar panel array generates during the day for use at night or when household power consumption exceeds the wattage your PV modules produce.  

The other is to connect your array and solar inverter to the utility grid via a bidirectional or smart meter.

Grid-tied systems fall back to utility grid electricity when consumption exceeds supply or at times when a PV array doesn’t generate electricity, i.e., every night.

In states with net metering programs, you can sell electricity your solar power system generates in excess of what you consume to your utility provider — though at a significantly lower rate than what you’ll pay for the grid power you consume.

Net metering is almost never a profitable endeavor… 

Any electricity you transmit to the grid will be credited to your energy bill. 

When residential solar panel systems first started seeing adoption in the US over 20 years ago, almost all of them were grid-tied.

Part of the reason for this was that battery storage was inefficient and expensive.

Additionally, selling excess power back to the grid was the only way to realize any value from the excess solar energy your array produced over what your household consumed.

However, recent innovations in solar battery chemistry — including the advent of affordable lithium iron phosphate (LFP/LiFePO4) batteries — have made off-grid and hybrid solar + storage systems a better option for most households.

A hybrid system like EcoFlow DELTA Pro Ultra can reduce electricity consumption by 75% — or eliminate bills completely.

Increasing self-consumption by using a whole home backup battery offers a better return on investment over time.

But what about during a power outage?

More crucially for many homeowners, hybrid solar systems continue to output electricity during power outages and can provide home energy security.

Grid-tied solar panel systems don’t work during a blackout.

Why Do Grid-Tied Solar Panel Systems Fail During a Blackout?

Grid-tied solar power systems shut down instantaneously during blackouts and extended power outages.

PV modules continue to generate electricity during daylight hours, but you won’t be able to access it unless you have an off-grid or hybrid system with solar battery storage.

Photovoltaic systems without storage must include an automatic shutdown mechanism for permission to connect to a bidirectional or smart meter that transmits electricity to the utility grid.  

It’s not that grid-tied PV systems “fail” during a blackout… 

Automatic shutdown is a necessity for conventional grid-tied systems and they’re designed with the functionality built-in.

In other words, auto-shutdown is a feature — not a bug.

Why Don’t Grid-Tied Solar Panel Systems Work During Power Outages?    

Grid-connected renewable energy systems are designed to supplement electricity from a utility provider — not replace it.

Grid-tied solar panel systems shut down immediately during a blackout and remain offline for the duration of the outage.

Auto-shutdown is required for the following reasons.

Anti-Islanding Protection

All customers of a utility grid provider are interconnected.

There are exceptions to the rule, such as microgrids that serve a localized community…

But even inside a microgrid — also known as a distributed energy resource (DER) — electricity consumers are connected to each other and the DER as a whole.

Grid-tied solar panel systems both consume and transmit electricity to the grid…

During a blackout, grid-connected renewable energy systems that don’t automatically shut down continue sending electricity through power lines, potentially creating an “island.”

An electricity island is a portion of the overall grid that continues to carry power from sources other than the utility provider during a power outage.

Uncontrolled islanding poses serious risks to utility workers and the stability of the grid.

Protection from the potentially devastating impacts of islanding is the primary reason grid-tied solar panel systems shut down in a blackout.

Without anti-islanding protection, the following outcomes could occur.

Utility Worker Injury or Death    

Power outages in the United States are typically caused by severe weather events, natural disasters, or equipment failures.

Rolling blackouts — also known as emergency scheduled power outages — are still relatively rare in the US but are becoming more frequent as electricity demand increases, especially during hot summer months.

When utility workers repair grid infrastructure damage, power is turned off to the affected section to ensure their safety. 

Power shutdown is typically achieved by de-energizing circuits at the transformer or distributor serving a localized area.

Depending on the nature and extent of the damage, broader sections of the grid may need to be isolated to ensure worker safety and further damage to infrastructure.

If anti-islanding protections — like auto-shutdown for grid-tied solar power systems — aren’t in place, energizing of the power lines will continue, potentially leading to serious injury or death by electrocution to workers repairing utility infrastructure. 

Grid Instability

The US electrical grid operates at a frequency of 60 Hz, and grid-connected solar inverters are designed to synchronize at that frequency.

During an outage, the grid’s frequency often fluctuates, and islanding could contribute further to instability, hampering recovery efforts.

Voltage Spikes 

When the grid attempts to restore power, if the solar system is out of sync, it can cause a significant and damaging voltage surge that could damage sensitive electronics as well as connected solar inverters.

The grid must be fully recovered and stable before grid-tied systems can go back online.

Building Code and Legal Compliance

For the above reasons, building and electrical codes require anti-islanding protection built into grid-tied systems.

Any attempt to circumvent auto-shutdown mechanisms is likely to be against the law and subject to substantial fines and/or imprisonment. 

Aside from personal liability, tampering with anti-islanding protection compromises the safety of your grid-tied solar power system, vulnerable utility workers, and the grid itself.

Do Solar + Storage Systems Work During Power Outages?

Hybrid solar power systems disconnect from the grid but continue supplying electricity from battery storage during an outage.

A solar generator like EcoFlow DELTA Pro 3 doesn’t transmit electricity to the grid through a bidirectional meter, but it can stay charged using AC power, solar panels, an inverter generator, and many other methods.

Integrate it with your home circuit board and wiring using EcoFlow Smart Home Panel 2 or a transfer switch, and you’ll get instantaneous switchover to battery backup during an outage. 

Can a Battery Backup System Power Your Entire Home During a Blackout?

Yes. A whole-home backup battery solution with sufficient AC output and storage capacity can operate all your appliances, devices, and HVAC systems during a blackout.

As long as you keep the batteries charged with solar panels, a gas or inverter generator, an 800W alternator (car) charger, or other available methods, they will provide electricity for the duration of the outage.

Whole-home standby generators like EcoFlow’s DELTA Series provide backup battery power that can keep almost any apartment or house running indefinitely during a blackout.

Sizing a whole house generator takes some work, but it’s well worth the effort to determine how much AC output and storage capacity you need to meet your home backup goals.

Begin by totaling up the starting and running watts of all the appliances you want to operate off-grid simultaneously. 

Get a quick ballpark estimate using our Appliance Wattage Chart & Energy Usage Calculator.

Next, decide how long you want to be able to run your home during an outage — a couple of hours, a day, a week, a month? Or indefinitely?

Learn how to calculate your household consumption in kilowatt-hours (kWh) here. 

Ensure that your battery storage capacity is sufficient to meet your goals.

It’s wise to exceed your estimated consumption by at least 20%.

Or charge a modular, expandable backup battery system like EcoFlow DELTA Pro Ultra, which is scalable up to 90kWh — enough to power most homes off-grid for a month.

Lastly, consider how many solar panels you need to keep your backup battery system charged for as long as you need during a blackout.

Frequently Asked Questions

Final Thoughts

Grid-tied solar panel systems helped kick-start the home solar energy revolution in the US. 

They can still be a viable option for some homeowners, especially those who live in areas with generous net metering payments that rarely experience blackouts.

Unfortunately, the increasing frequency of extreme weather events and aging utility infrastructure mean that being solely reliant on a functioning grid for electricity is no longer realistic.

Opting for an off-grid or hybrid solar power system increases self-consumption, maximizes ROI, and achieves home energy security even during extended power outages.

EcoFlow DELTA Pro Ultra is a highly scalable whole-home solar generator with backup battery storage that can power just about any home.

It’s just one of the many portable power station and solar generator models offered by EcoFlow to meet all your backup and off-grid power needs — from camping to running a house.

Check out our selection today.