Battery backup power vs. generators: which is right for you?

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If you live in an area with frequent power outages, you already know the benefits of having backup power installed at your home.

Propane, diesel, and natural gas-powered generators have long been the system of choice for homeowners and businesses that want to ensure that the lights stay on when the power goes out in the neighborhood. Now, an increasing number of people are considering newer, cleaner battery options like the Tesla Powerwall.

Battery backup power offers many of the same backup power functions as conventional generators but without the need for refueling. Read on for a comparison of battery backup options versus conventional generators, including a review of factors like cost, fuel supply, size, and maintenance.

Comparing battery backup and generator costs

The exact amount that you’ll pay to install backup power at your home or business depends on the amount of power you need and the equipment you choose. There are many standby generator options available in the $3,000 to $5,000 range that can power a standard American home. By comparison, a home backup battery will start at around $6,000 before installation costs, and in many cases, you’ll require multiple batteries to provide whole-home power. Altogether, you can expect to pay anywhere from $10,000 to $20,000 to install a battery backup system. If you use more energy than your neighbors, you’ll need to buy a bigger generator or more batteries, and you can expect the installation cost to add up to a few thousand dollars to your total price tag.

Savings with battery backup power

The upfront price you pay isn’t the only cost to keep in mind. If you install a generator, you also need to buy the fuel to keep it running. Fuel costs can add up if you frequently rely on your generator – this is especially the case if you also need to pay for the delivery of fuel to your home or business.

By comparison, if you install a battery for backup power, you can pair it with a solar energy system to charge it with renewable energy from the sun. This will add to your upfront cost (an average 6-kilowatt solar panel system will cost, on average, $17,880 before incentives), but over time it can save you tens of thousands of dollars on your electric bill.

Even without solar, your battery might be able to save you money on your electric bill. Some utilities have time-of-use (TOU) electric rates, which vary throughout the day. If you have TOU rates, a battery can actually result in lower electric bills by providing an alternative source of electricity when rates are high.


Fuel supply for your backup power

The source of energy for your home backup power system is another consideration when you’re comparing your options.

Generators are usually powered by diesel, liquid propane, or natural gas. Your generator can continue to run as long as you have the fuel to supply your generator, and some generators can even be connected to an existing natural gas line. If you don’t have access to a natural gas line, you should expect to refill your generator as needed.

By comparison, a home battery backup system runs on electricity and can be charged either from the grid or from a rooftop solar panel system. If you design a solar plus storage system for off-grid backup power, you can recharge when the grid goes down, adding an extra layer of security for situations where you might be worried about having access to fuel for a generator. (Not all home battery systems can be recharged during power outages, so make sure that your installer knows that this feature is crucial to you.)

Size/power load for backup power options

When you’re comparing your backup power options, think about what you need to keep running when the grid goes down.

If you just want to keep the lights on in a power outage, most batteries will do the job. Many homeowners who choose batteries for backup power are comfortable knowing that “critical loads” like power outlets, lights, and small appliances will be powered in the event of a power outage.

However, not all batteries are capable of quickly discharging enough electricity to get energy-intensive equipment up and running. If your home relies on a sump pump, well pump, or other equipment that uses a lot of power to start up, you’ll need to install a battery like the Pika Energy Harbor Battery that is specifically intended for backup power.

If you install a conventional generator, you won’t have to worry about critical loads. As long as you choose a generator that is sized properly by your installer, you should be able to keep your home or business running without issue, assuming you have adequate fuel onsite.

Operating & maintaining your backup power system

Generators powered by propane or diesel can be hard to ignore when they’re running. One major advantage of a battery backup system is that it operates quietly and doesn’t burn any fuel, unlike a conventional gas-powered generator. As a result, you don’t have to deal with exhaust fumes or other polluting emissions – a win for the environment and for the air quality around you.

Generators powered by fossil fuels like natural gas or diesel can also have higher maintenance requirements than battery backup options. In addition to refueling, some generators need to be run and tested regularly to ensure that they’ll be operational when you need them most.

Before you buy, compare solar & batteries to other generator options

Diesel, propane and natural gas-powered generators are relatively inexpensive and easy to size for your property’s power needs, but there are also benefits to installing battery backup power at your home or business. When paired with solar, you can actually save money on your electric bills, and batteries offer clean, quiet power that you can’t get with a conventional generator.

If you’re talking to a contractor about installing a generator, consider getting quotes for solar systems that include batteries on the EnergySage Solar Marketplace. On EnergySage, you can easily compare your solar options, and see both upfront cost and long-term savings information without even having to pick up the phone. When you join, simply note in your property preferences that you’re looking for a system that includes backup power.


5 thoughts on “Battery backup power vs. generators: which is right for you?

  1. Michael Lee

    What I have found is that batteries work well as a short-term solution but less well long-term. Batteries can be portable like a clip on genset but they need to be recharged after use. Both really depend on what you need it for.

  2. Norman Colman

    I want a battery as a back up. lights tv plus modem for internet ,and fridge
    Can I charge battery using base load power from the grid..
    backup say 2 day blackout. how much for battery


  3. Anthony Hugh

    Hi there. It seems that you have left out a lot of critical information that would help people make an informed decision. While I understand (as a solar system company owner) the desire to move people toward battery backup systems. We should not lose sight of the ongoing costs for these systems. You mentioned the ongoing costs for a generator back up (fuel, maintenance etc.), however, Battery back up systems have huge ongoing costs. Since most conventional battery systems do not work with micro-inverters, you will need a larger solar system, in the first place, to generate the power you need. As well, batteries do wear out and will need replacing way before a well maintained quality generator will. Next is the power inverter and associated equipment that goes with a conventional battery back up system. All of this equipment will need to be replaced and generally (based on warranty and experience) in a far shorter time than a quality generator.

    A comparable battery back up system costs thousands of dollars more than a generator solution – up front, and, when you compare the actual ongoing costs, remains far more expensive in the long run. In fact, with most conventional battery back up systems, you will replace the entire system long before you need to replace the generator.

    My experience is that most people want to reduce their power costs, and that is why they go solar in the first place. Adding a back up power supply, for most, is a luxury item. Keeping the lights on, the internet working and the food cold should not cost more than the solar system itself.

    It is environmentally responsible to use as little fossil fuel as possible, however, the trade off between battery back up and a generator is, in my opinion, far too expensive both short and long term, for most people. This option remains an overly expensive consideration.

  4. Lisa A Miranda

    Mr. Anthony, what if I learn to refurbish my own batteries as they wear out? I plan on researching that because if there were an outage and it was for a long time Solar power alone wouldnt help. but to use solar pannels would give me power and recharge it. and if I had a way of learning the maintenance instead of paying for it might I save the cost you are referring to? these solar power companies know us comsumers think that solar power provides us with protection if power goes out. But thats not true. I would love to get off the grid, save money and have power even if city power is down.. am I living in a pipe dream. I am on a fixed income and can not afford the whole shabang.

  5. vikingvista

    Another consideration is that with a mechanical generator, the power will go out for a few seconds while the generator starts up. A battery backup, on the other hand, can be set up to be perpetually supplying power, so that when the utility power is lost, the battery will seamlessly kick in, without so much as a flickering light.

    Also, a battery will eventually run out of power. A generator hooked up to a gas line can provide for your house indefinitely.

    A propane powered generator will allow you to be off the gas grid, which can be important during a natural disaster like a hurricane or earthquake that knocks out the gas grid. But you will need to truck in your propane supply as it runs out.

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