Battery Storage or Generator?


Power outages can be more than a minor nuisance. Extreme weather can knock out the electric grid for days to weeks at a time. Even for shorter outage durations, those with electricity-dependent medical equipment or who have home-based businesses are deeply impacted by loss of power.

Installing solar panels and a battery storage system requires expensive upfront costs, but some of these costs can be offset through year-round energy savings. Photo courtesy of Tesla.

Recent intense, severe weather events are prompting many to consider off-grid solutions for energy during prolonged power outages. Gas-powered generators are a traditional choice for residential power generation, but new battery storage systems coupled with solar panels can also be a solution. There are pros and cons for each type of backup power system, so consumers should consider their personal power needs and budget.

Sizing your home energy needs is a first step to deciding which system to install. Evaluate if it is necessary to power the whole house or just a few critical appliances. Tally up the reported energy use of each appliance that needs to remain operational to get a rough estimate of minimal energy needs. This can be a guide to choosing your backup power option with enough capacity.

Gas-powered generators have the lowest upfront costs. These can either be portable, permanent, or standby systems. Portable generators typically cost between $400 and $1,500 and can use roughly 20 gallons of gasoline per day. Gas-powered generators are noisy and have the least output, making them more suited to occasional, short-duration power outages.

Permanent (standby) generators are connected directly to a residence and can be turned on automatically in the event of a power outage. Photo courtesy of Kohler

Portable generators can be manually connected to a circuit panel, but an electrician must install a manual transfer switch to protect appliances from a power surge once electricity is restored. If not connected to a circuit breaker, appliances can be plugged directly into the generator but require a long, heavy-duty extension cord for safe operation.

Portable generators also must be operated in well-ventilated areas and shielded from wet weather. The U.S. Consumer Product Safety Commission estimates there are 80 deaths per year from carbon monoxide (CO) exposure due to improperly operated portable generators. Availability of gasoline can also be a challenge during severe weather, and long-term storage of gasoline requires proper containers and stabilizers.

Permanent, or standby, generators typically cost $2,000 to $5,000 and can have installation costs that run from a few thousand dollars to $10,000. These are connected directly to a residence and can be turned on automatically in the event of a power outage. Permanent generators can run on natural gas or propane. If connected to a natural gas line, these can run indefinitely and power an entire home. Standby generators are suitable for frequent outages or occasional but sustained outages.

Overall expenses for a solar and battery storage combination are much higher than a generator. The National Renewable Energy Lab estimates the average U.S. cost for installation to be around $1,200 to $1,500 per kilowatt of system capacity. This estimate includes the cost of the battery, installation, permitting, and inspection costs and is done at the time of solar panel installation. Adding a battery storage system to an existing solar installation is significantly more expensive and may require an inverter change.

Compared to generators, this option is quieter and does not create local emissions like CO. The upside of a solar and battery storage system is the ability to offset the higher initial investment costs through year-round energy savings. Depending on the utility, consumers may also take advantage of time-of-use rates and use stored energy during times when the cost of energy is highest. However, a battery storage system can only provide 10 to 15 hours of continuous power. In weather situations that limit solar power generation, this would not be a long-term solution.

There can be sizeable upfront costs for both generators and battery storage systems, but backup systems can bring great peace of mind when the power goes out. If you have questions about backup power options, contact your local electric cooperative.

Katherine Loving writes on consumer and cooperative affairs for the National Rural Electric Cooperative Association, the national trade association representing more than 900 local electric cooperatives.