The risk of grid blackouts is rising, and the Department of Energy said weather-related power outages due to extreme weather rose by 80% in the United States from 2011 through 2023. With the U.S. grid aging in need in of repair, homeowners are turning to backup power at home.

Two main options for backup power exist: traditional gas generators and battery energy storage systems. How do they compare?

Gas generators typically run on diesel, propane, or natural gas. Home battery energy storage systems are most commonly paired with a rooftop solar array.

When it comes to upfront cost, gas generators have an advantage. Based on a CNET product review, an average home battery system costs between $10,000 to $20,000. A standby gas generator costs about $7,000 to $15,000, said CNET. However, battery energy storage systems costs are reduced by 30% through the federal Investment Tax Credit, whether they are paired with a solar installation or not.

Despite their upfront cost, home batteries typically have lower operating and refueling costs, though this varies by the price of electricity or cost of rooftop solar. Batteries can be charged by either the grid or a rooftop solar array, refueling themselves. The cost to refuel gas generators is typically more expensive, though this depends widely on the cost of diesel, propane or natural gas in your area.

The lifetime of a home battery is generally about 10 years, while a generator can operate for 20 years or more, albeit with regular maintenance and repair costs to remain operational.

The chart below from solar and storage marketplace operator EnergySage draws expected costs over 20 years for battery storage versus generators, assuming a home battery installation includes the cost of installing solar: 

From an operational standpoint, a home battery has advantages. The units are typically smaller, can be installed inside a garage and wall-mounted, or installed outside. Gas generators are typically quite noisy in their operation.  

Gas generators also pose a health hazard, producing carbon monoxide. If your gas generator is portable, it is critical to operate it outside, as many people have died from carbon monoxide exposure due to indoor gas generator operation, said OSHA.

“If you own a portable generator, remember to place it outdoors at least 20 feet from your home’s doors, windows, or vents, said the Texas Department of Insurance. “Keeping a distance helps protect you from carbon monoxide gas, which is colorless, odorless, and potentially deadly.”

Generators typically have an advantage in their power output. While whole-home backup with batteries is possible, some homes may require two batteries or more to back up the whole home. With a single battery, customers typically work with a solar installer to select several critical breakers in the main panel to back up. 

In several states, batteries also have the advantage of being able to participate in electricity grid export programs, often referred to as virtual power plants (VPP). Battery owners can be paid by VPP program operators to enroll their batteries to dispatch electricity to the local grid during peak demand hours. Solar installer Sunrun, for example, pays its customers $400 per year to enroll in its VPP program in select states.

The verdict: with more flexible installation location options, a quiet, sleeker design, and effortless refueling, home batteries present an easier-to-maintain backup power option. Generators have an advantage in upfront cost, but over the life of refueling and repairs, they may pose a higher lifetime cost. What’s more, generators are noisy and pose local health risks with carbon monoxide emissions.