Tesla Powerwall Replacing A Generator – What You Need to Know

Tesla Powerwall Replacing A Generator - What You Need to Know

The thought of losing power in your home can be daunting. In addition to the loss of creature comforts (e.g., a/c and Wi-Fi), you can also lose the food in your freezer if it goes too long without power. In the past, a backup generator was your primary option when it came to maintaining power through an outage. But now, there are home batteries such as the Tesla Powerwall.

When replacing your generator with a Tesla Powerwall, you will need to know your home’s energy needs: powering an entire home requires at least two batteries, but your home may need more. Tesla Powerwalls can also be combined with other power systems in order to maximize power reserves.

Of course, there are more reasons to consider investing in battery power for your home. It’s better for the environment for starters. Also, it could save you thousands on your energy bills over the coming years. Read on to learn more about what you need to know when adding a Tesla Powerwall system to your home.

The Advantages of a Powerwall Over a Generator

Maybe you aren’t even sure that you want to replace your generator yet. That’s fine; it’s your home, and researching what will be best is a smart choice. Here are some of the advantages that Powerwall offers when compared to a generator:

You Don’t Have to Buy Fuel for It

The most common fuels for home generator use are natural gas, diesel, and gasoline. Natural gas is the most abundant and can possibly be accessed via local utilities directly to your home. Diesel and gasoline are typically easy to come by, but if you don’t have the fuel on hand when you need it, you’ll have to contend with other customers.

The thing about having gas or diesel kept at home is that it doesn’t last forever. Diesel has a shelf life of about a year and a half to two years. Gasoline only has a shelf life of approximately one year. In addition to the risk of your fuel going bad, gasoline is volatile and highly flammable. Storing incorrectly can lead to fires, leaks, and explosions.

In the event of a power outage, a standby generator fueled by natural gas may cost between $20 and $30 per day to operate under a 50% load.  The cost of diesel and gasoline will fluctuate with the rise and fall of demand. Also, if your region is experiencing power outages due to a storm, the gas station pumps may not work unless the store has backup power.

With a Powerwall battery, your electricity is stored for later use in the event of an outage and can be recharged using solar power. You may also be able to store your electricity when it is at its cheapest rate.

Source: Assurance Power Systems; CK Power; Home Power Systems; National Ag Safety Database

A Powerwall Isn’t as Loud as a Generator

Keep in mind that the noise level of generators is typically measured from a distance of about 7 meters; if you move closer, the noise will be louder. The noise created by your generator can vary based on a few factors:

  • Fuel source – diesel generators tend to be the loudest.
  • Size – this is where your noise will likely vary the most. A smaller generator will tend to run quieter but will not be able to power as much.
  • Portable vs. Standby – Portable generators tend to be louder than standby generators.

Most mid to large size (6.5 – 14 kW) portable generators produce noise levels ranging from 75 to 85 dB (at a distance of about 7 meters). For reference, a hairdryer typically has a noise level of 70 dB, and a lawnmower typically has a noise level of 90 dB. Extended exposure to noise levels of 85 dB or more can cause hearing damage.

At a distance of only 1 meter, the Tesla Powerwall’s noise level tends to be 40 dB or less. For reference, the ambient noise of a library is typically around 40 dB.

Source: Hy-Tech Roof Drains; Midwest Generator Solutions; IAC Acoustics

It’s Better for The Environment

Your generator’s carbon footprint will depend on how much you use it and what type of fuel. Of the big three fuels (natural gas, diesel, and gasoline), natural gas produces the least amount of emissions at .92 pounds of CO2 per kWh, according to the US Energy Information Administration. Petroleum products (diesel and gasoline) produce 2.11 pounds per kWh.

Know the Power Needs for Your Home

It isn’t terribly difficult to figure out how much energy your household consumes; the data should be provided on your energy bill. If you have all of your bills for the year, you should be able to calculate how much you use on average as well as determine when and how much you use when your energy consumption is at its highest. 

In addition to knowing how much energy it takes to run the devices in your home, you need to calculate how much energy it takes to start that device. Once you’ve estimated how much power it would take to start each device in your home, you should have a good idea of the capacity you need for your home.

One Tesla Powerwall has a usable capacity of 12.2 kWh (kilowatt-hours), with a 7 kW of peak demand power and 5 kW of constant power. One battery will be enough to power your lights, electrical outlets, and any 120-volt small appliances. This system will not operate any large devices.

A system with two batteries will allow you to run a central air conditioning unit, electric stove/oven, and an electric well pump. With three batteries, you can run the aforementioned appliances in addition to another air conditioning unit, electric dryer, electric water heater, and pool equipment. The more you intend to run, the more battery power you will need.

Source: Tesla; Vinyasun

Be Aware of the Cost

If you’re considering making the switch to energy independence with a Tesla Powerwall battery system, know that it will not be cheap. Not upfront, at least. But it’s important to understand that this is an investment in not only your home, but the environment.

Parts and Labor

On Tesla’s website, you can enter your address and average monthly electric bill, and the site will recommend an amount of Powerwalls to install based upon your estimated energy needs. They will also give a quote that includes the price of the Powerwalls ($7000 each), the price of a Tesla Gateway ($1000), and installation ($2500).

  • Tesla Powerwall – the rechargeable battery component
  • Tesla Gateway – the component that allows you to manage and monitor your energy consumption

That is assuming you are having your Powerwall installed by Tesla. If they don’t service your area, you will have to find a certified installer. That is where your prices will begin to vary. Several sites state the batteries cost between $6500- $6700, with the hardware needed to support the battery costing around $1100.

Does Tesla Offer Discounts on Powerwall?

Tesla solar is already the lowest cost-per-watt solar on the market, but are there any other ways to save money when ordering?

In short, the only way to get a discount on Tesla solar products is by using an existing Tesla owners “referral link” when ordering.

Tesla has did this same “referral program” concept with it’s vehicles and essentially it allows new customers to get a discount on their purchase by using an existing customers personal referral link.

In regards to Tesla solar discounts, using a Tesla referral link when ordering will save you $300 off solar panels or $500 off solar roof.

The referral discounts are typically only available for a limited time before Tesla stops offering the discount, so take advantage of the savings while you can.

tesla solar panel discount


While the price tag may be hefty, some potential incentives can offset the cost.

  • Federal Tax Credit – If your Powerwall is installed on a new or preexisting solar system and is charged solely with solar energy. To qualify, your Powerwall must be charged entirely by solar power. This Tax Credit is scheduled to be phased out by 2022.
  • State Incentives – In addition to the federal tax credit, it’s possible that your state and municipality may offer incentives, usually a rebate.
  • Local Incentives – In addition to the federal tax credit and the potential state rebate, your local municipality and utility services may offer incentives such as discounted electricity rates or cash back.

Source: SunSource Homes; Washington Generators; Tesla

Know Where You Want to Put Your Powerwall

The options for where to place your Powerwall are much more flexible than your options for where to place a generator. For starters, generators need to be kept outside; running a generator in a closed space is hazardous and can lead to carbon monoxide poisoning. No matter how loud your generator is (and it will be loud), carbon monoxide is a silent killer. 

Powerwalls can be placed indoors or outdoors, don’t produce carbon monoxide, are water and dust resistant, and can operate in temperatures ranging from -4 to 122 degrees Fahrenheit (though the optimal range is 32 to 86 degrees F). While they are water-resistant, they should not be installed in areas susceptible to flooding nor near water sources.

Powerwalls can be mounted on a wall, side-by-side, or stacked in groups of three front-to-back. Each Powerwall is 45.3 inches long by 29.6 inches wide by 5.75 inches deep and weighs 250 lbs. If stacking, the batteries need to be floor mounted and anchored to a nearby wall. (You weren’t expecting to hang 500 to 750 lbs. from the wall, were you?)

The Gateway is 26 inches long by 16 inches wide by 6 inches deep and weighs 45 lbs. and should be mounted on a wall.

Decide on an Energy Source

While your generator will typically be powered by a fuel source such as diesel, liquid propane, or natural gas, your Powerwall system runs on electricity. Each battery only has a usable capacity of 12.2 kWh, so they have to be recharged somehow. The two primary sources of electricity for your Powerwall battery system will be:

  • A Power Grid – Electricity is produced and distributed across power lines at high voltages before it reaches a transformer, which converts high voltage to low voltage so that it can be used. This is the electricity you are paying the power company for.
  • Solar power – Solar panels placed on your home may also be used to charge your Powerwall batteries when the grid is down or if you don’t wish to use the grid at all.

Power Grid

Switching to battery power for your home can reduce your carbon footprint. Most of the electricity produced is done so using turbine-driven generators. These turbines are powered by a variety of energy sources. The generator converts the rotating turbine’s kinetic energy into electricity, which can be distributed to consumers.

Turbine Electric Generator Energy Sources
FuelHow It WorksEnvironmental ImpactShare of Electricity Generated (US)
Fossil Fuels (coal, oil, natural gas)  Burned to heat water into steam, which drives turbinesCause of 99% of electricity-related CO2 emissions.62.6%
NuclearWater heated by nuclear fission creates steam, which drives turbinesDoes not directly produce CO2 emissions but does produce radioactive waste.19.6%
WindThe wind passes through blades, which spins the rotor of the turbines.Carbon neutral, but can damage wildlife habitats and poses a threat to flying wildlife.7.1%
Hydro  Running water passes through which drives turbinesCarbon neutral, but can damage wildlife habitats and damage water quality.7%
SolarPhotovoltaic (PV) cells convert sunlight into energy or Solar Thermal Energy is used to heat water, creating steam.Clearing of land can damage the ecosystem. More to be addressed in the next section.1.7%
Biomass (Wood, landfill gas, municipal solid waste)Burned to heat water into steam, which drives turbinesProduces air pollution. Said to be carbon neutral before the plant sources capture as much CO2 as is created.1.4%

Some fuel sources have a more significant impact on the environment than others. The thing is, you as the consumer don’t have much say in where your power comes from.

Most utility companies charge a rate based on the seasonal average cost of producing and providing electricity. However, your utility’s rates may fluctuate throughout the day, costing more during peak hours of production.  If this is the case, you can charge your Powerwall when electricity is at its cheapest and switch to backup power when it is most expensive.

Solar Power

While much better for the environment than plants that burn fossil fuels, large solar power plants do have their small disadvantages as well. Land that is cleared to make room for the plant can have a long-term effect on the ecosystem. Also, solar power plants that use thermal energy create a beam of concentrated light that can kill wildlife that flies into the beam.

But to be clear: the solar power that you will use to power your home will not have the same negative environmental impact as the large-scale solar power plants. It’s the same technology, but on a much smaller scale.

Installing solar power with your Powerwall is recommended as it will give you the most energy independence. Your solar power can run your home and charge your batteries during the day, and you can switch to battery power at night. An added bonus to this is the grid may even pay you for any surplus energy you create. You won’t just save money; you can make revenue.

One detail that should be noted: Tesla states that if you install your Powerwall with solar, charging from the grid will not be an option.

Source: US Energy Information Administration; Hindawi; Manufacturing.net; Office of Energy Efficiency & Renewable Energy; Young African Leaders Initiative

Rather Than Replace, You Could Supplement

This is an article about replacing your generator with a Tesla Powerwall. That implies that you already have a generator. You can replace the generator if that’s truly what you wish to do. You could also add the Powerwall battery system and keep the generator on standby in case of emergency.

If you are not using solar power in conjunction with your Powerwall system, the batteries will only last so long if the power fails. Generators should never be used to charge the Powerwall batteries, but you can use them to power your home after the batteries have reached their capacity.

What if you are using solar power with your system? You can still keep the generator. One would assume it’s been paid for. Hopefully, you will not need it, but it’s better to have and not need than to need and not have. One example that comes to mind is hurricanes.

Along the coast of the Gulf of Mexico, hurricanes cause catastrophic damage. Homes and businesses can be without power for weeks. It would be great to have solar power and a battery system at that time. But what if your solar panels are damaged in the storm? Or worse, the storm blows that part of the roof off? That’s when a backup to the backup comes in handy.

Source: Sunnova


If you’re planning to install a Tesla Powerwall battery system in your home, consider installing solar panels as well if you don’t already have them. This will allow you to rely less on the power grid and fossil fuels for your home energy needs. It will cost upfront, but the combined solar energy and battery storage can save money over the years.

Tesla Powerwall systems are cleaner, more efficient, and more versatile than backup and portable generators. You can replace your generator, or you can keep your generator on standby in case of extreme emergencies. Remember: do not attempt to charge your Powerwall with a generator.

Solar Discounts:

Greg Gottfried

The articles here on ThatTeslaChannel.com are created by Greg Gottfried, a Tesla vehicle and Tesla solar expert with nearly half a decade of hands-on experience. Being a Tesla owner allows Greg to fact-check information and personally try new scenarios out before publishing an article explaining the process.

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