Sep 07
What is the Best Backup Source for Power? Energy Storage VS. Generator | Solar Insure

What is the Best Backup Source for Power? Energy Storage VS. Generator

What is the Best Backup Source for Power? Energy Storage VS. Generator | Solar Insure

The average time a homeowner in the U.S. spends without power is about 6-8 hours per year, depending on the time of year and location. Some regions of the country spend much more time without power due to life-threatening and extreme weather conditions. As more weather events result from climate change, more people are choosing to backup solar and grid energy with generators and storage batteries. But which is better? What do they both do? We’ll explore some comparisons for the best backup power source. 

What do generators and batteries have in common? 

Where generators and batteries converge is their capacity for backup power. The prevalence of blackouts is a growing occurrence from extreme heat events, extreme winter, high wind events, and fires. If the grid goes offline, you can shift your energy source to a backup source. The similarities of a battery and generator pretty much stop at this function, as the devices are very different in upkeep and functionality. We’ll explore the main difference so you can determine the best solution for your particular set of circumstances.

How do generators and batteries differ? 


Generators are a significant source of direct air pollution from natural gas and diesel power. In some cases, these can be dangerous sources of carbon monoxide. It’s not just air pollution that you have to consider with generators; it’s also noise pollution, as generators are generally very loud. Generators also tend to be an eye sore, as they’re required to be placed outdoors, 

Batteries don’t have a direct air pollution output, but that doesn’t mean their backend manufacturing or post-recycling efforts are free of pollution. But, to an end-user, you don’t risk the same carbon monoxide risks as a generator. You can put a battery indoors as long as the ambient temperature supports the battery temperature storage range. In addition, batteries tend to be quiet, relieving yourself and your neighbors of obnoxious noise. 


Generators require more oversight than a battery. Since generators don’t interact with the grid, they are only used when you’re not connected to the grid or the grid goes offline; they require routine checks. Here’s a maintenance checklist you can expect for the upkeep of a generator:

  • Perform a visual inspection (weekly)
  • Turn on and run the generator (weekly)
  • Inspect fluid levels (weekly)
  • Inspect for leaks (weekly)
  • Inspect auto mode (weekly)
  • Clean generator (monthly)
  • Clean surrounding area (monthly)
  • Inspect engine coolant levels (monthly)
  • Inspect battery charger (monthly)
  • Inspect engine oil levels (monthly)
  • Change oil (annual)
  • Change the oil filter, fuel filter, and air filter (annual)
  • Perform a flush for the cooling system (annual)
  • Inspect wiring/electrical system (annual)
  • Change spark plugs (annual)
  • Test transfer switch (annual)

Batteries don’t require the same time-consuming maintenance. With batteries, you can essentially set it and forget it, as they interact with the grid and can be managed more intelligently – as long as the placement and installation are executed correctly. The most common lithium-ion batteries used in solar-plus storage are lithium iron phosphate (LFP) and lithium nickel manganese cobalt oxide (NMC). LFP and NMC batteries don’t have any special maintenance requirements; the biggest concern is ensuring the battery stays within recommended temperature ranges of –40°F to 122°F. 

Here’s a maintenance checklist you can expect for the upkeep of a battery:

  • No maintenance

Cost vs. Value

When considering the cost of backup power, it becomes a matter of determining whether you want to save overall or save in the short run. 

Generators cost less upfront; on average, for residential customers, a California resident will pay about $3,500 for a generator and receive zero tax incentives, as generators are not subsidized. Maintenance costs are about $1,000 per year, a low entry point for getting backup power, and fueling the generator on the low end costs about $1,600 per year. The big problem for generators is that they can only be used when the grid goes offline, so you must purchase energy from the grid when there’s no blackout, which can cost about $51,300 per year on average (see graph). 

Batteries cost more upfront, but you get more value for your money. You can also leverage the many state and federal tax incentives available when purchasing new battery storage systems. With batteries, you’re able to draw energy from the grid during low usage hours and use that saved energy when peak hours hit your wallet the hardest. Batteries can be used for load shifting and strategizing your energy costs. You can also maximize your energy strategy by sourcing your own solar panels. This is where the great cost savings come into play; when compared to a generator, an overview for the year could look like a roundabout $22,000 savings when choosing a battery with solar.

Source: Energy Sage


As of 2021, the standard warranty on a generator is five years. Solar Insure offers a battery warranty of 20 years below 70% production in order to qualify for battery replacement. There is currently no other coverage that compares to this battery coverage timeframe. The reason is that batteries don’t require any special maintenance and cycle daily, while generators require a long list of maintenance which lack thereof is usually the culprit for failure. 


Generators are located outdoors and must be started manually, which makes them a potential danger if you or a loved one have to go outside in severe weather to jump-start the power. In addition, natural gas and diesel storage run the risk of explosion in a high heat event. 

Batteries cycle daily and are automatically turned on when power is needed. They are often located safely indoors, so in the event of extreme weather, you don’t have to go outside if you want to check them. There’s nothing you need to do with a battery unless it begins to experience a failure, making it a great energy backup when dangerous weather strikes.


When making the best backup power decision, you’ll also want to consider your specific factors. Generators can be helpful in disastrous situations but will require a constant flow of fuel, and in a disaster, refueling a generator can become a challenge. Batteries powered by solar panels can continue generating power as long as the system wasn’t damaged in the event. 

Another functionality feature to consider is that you can’t power a generator from the grid but can power a battery from the grid.

Future-proofing your energy backup system

When evaluating a backup power system for purchase, you’ll want to consider future projections on fuel costs, grid expenses, severe weather patterns, anticipated supply chain issues, and your personal life factors. These are all variables that make a large purchase future-proof, meaning your system can weather future events that are anticipated to take place. 

There are several considerations to make; however, comparing generators to batteries is challenging beyond the function of backup power. Battery storage is in a class of its own, with better overall costs, no maintenance, safety, and functionality to stay connected. 

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