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Batteries vs. gas-powered generators for backup power

Last updated 1/2/2019

Finding the right source of backup power for your home is an important safety measure in the event that the electrical grid fails or is damaged. Two popular solutions today are home batteries and gas-powered generators, each of which offers their own perks and drawbacks.

What differentiates batteries and generators?

There are several important points to consider when choosing a home energy backup power solution:

Price

Currently, most backup batteries have a higher upfront price tag than a typical gas generator. This higher price is a factor of the costs of production and installation, among other variable costs. Although a battery storage system may cost more upfront than a traditional generator, you can expect the total lifetime cost of a generator to equal or exceed that of a battery system. This is due to a few main factors: 

  • Maintenance and service: Batteries require little to no maintenance, while generators need yearly service to make sure they are operational, safe, and clean.
  • Fuel costs: If you connect your battery to a solar energy system, it can be recharged with electricity for free using energy from the sun. With a generator, you need to buy fuel to burn for power.
  • Incentives: There are federal incentives available for purchasing a battery storage system, and often additional state and local incentives on top. Generators are usually not monetarily incentivized.

All things considered, the total lifetime cost of batteries and generators are similar, and batteries will only become less expensive as production costs fall in the coming years.

An additional financial factor to consider when deciding which backup energy system is right for you is the product warranty. Home batteries come with warranties similar to those for electric vehicle batteries, with guaranteed cycles instead of miles driven. Typical battery warranties last for 10+ years and guarantee your battery will carry a certain percentage of its original capacity by the end of the warranty period (or after a specified number of charge and drain cycles). By contrast, generators come with shorter term warranties around 2-3 years and only cover defects in manufacturing. Damage due to environmental factors like corrosion or freezing are usually not covered.

Reliability

The main con to using batteries for backup power as compared to fossil fuel generators is power output and storage capacity. If you plan on running a large, power-hungry home on backup power for weeks at a time, you likely won’t be able to store enough energy in a single battery. You can partially combat this problem by installing multiple batteries, thus increasing your storage capacity. However, this can be cost prohibitive for many people. Generators, on the other hand, can link directly into your home gas line which allows them to run continuously without a limit, as long as there is gas being pumped to your home. However, running a generator for weeks at a time will make a substantial dent in your bank account while releasing pollutants into the environment.

A reliable backup power system should have the ability to operate for long periods of time. Gas-powered generators usually run on natural gas or gasoline, and as long as you have fuel to pump into your generator it will keep operating barring mechanical problems. If you supply your generator with gas from small storage tanks and not a direct gas line, it will only be able to produce power for you until that fuel runs out. Batteries have the advantage over generators in terms of power duration if you connect your battery to a solar energy system, which can continue to recharge your battery as long as the sun continues to rise in the morning.

Other factors

Price and reliability will be the most important deciding factors between batteries and a generator for most consumers, but there are further differences between the two backup power methods. Here are a few to consider:

  • Smart home integration: Battery companies are beginning to develop companion apps for their products, allowing you to monitor energy use and trends when you tap stored electricity. As the concept of a ‘smart home’ moves from concept into consumer reality, having a connected energy storage system is an important component of a comprehensive home energy system.
  • Environmental factors: A gas-powered generator releases carbon dioxide and other pollutants, and is not the most environmentally responsible method of backup power. A home battery eliminates air pollution and reduces your home’s carbon footprint, as long as it is powered by solar panels.
  • Noise and “exercise”: Two minor inconveniences that come with gas generators are noise and the need to run your generator for the occasional test. Unlike a battery, generators are loud and need to be placed carefully to avoid excessive noise levels. Generators also need to be run occasionally (known as “exercising”) between uses to make sure that their mechanical systems are tuned up and safe to run when you actually need backup power.

Solar + battery storage: the optimal energy storage solution

A cost-effective, flexible, environmentally friendly, and reliable home energy storage option for homeowners is to pair a solar energy system with a home battery. Instead of charging your battery from the grid, linking solar panels to batteries allows you to generate and store electricity for free. 

Homes with solar plus storage systems can continue to generate and store power when the electrical grid is down, as solar panels only need sunlight to generate electricity. Combining a battery storage product with a solar array may even allow you to run your home on backup power indefinitely, like a gas-powered generator but without the fuel costs, noise, and pollution. Your solar panels generate power during each day, which can be stored in batteries and drawn out at night, providing a clean way to stay online in the case of an extreme weather event or grid outage.

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