Tesla Powerwall: Purpose, Cost, Alternatives, Getting One Installed & Is it Worth It?

February 5 2021, 14:35 GMT

With well over 100,000 Powerwalls installed to date, Tesla has rapidly changed the home solar power industry, increasing efficiency and energy savings for many homeowners. 

On the back of the growth of renewable energies and an increasingly attractive brand image, Tesla dominates the media associated with domestic solar storage.

But what is a Powerwall and do you need one? 

What is the Tesla Powerwall?

In its purest form, the Tesla Powerwall is a rechargeable battery designed to work in conjunction with solar panels for home use. It stores power during the day, which would otherwise be distributed on the energy grid, for use during the night or even power outages. 

It greatly increases the efficiency of owning solar panels, extending their use from the daytime and into the nighttime, combatting the need to buy energy during non-productive hours. 

The Powerwall 1 was released by Tesla in 2015, with the current version, the Powerwall 2, being announced a year later. The Powerwall 2 marked a significant improvement from its predecessor with over double the capacity and triple the power output from a battery significantly smaller than the Powerwall 1. The current Powerwall uses lithium NMC (Nickel Manganese Cobaltbattery cells.

By April 2020 Tesla had installed 100,000 Powerwalls.

The Powerwall is a key development in the race for renewable energy, giving individual homeowners the power to be self-sufficient on solar energy.


What Does the Powerwall Do?

Powerwalls have three main uses: 


The primary function of the Powerwall is to extend the use of solar energy into the night, roughly doubling the amount of energy that you can use from your solar panels.


With 13.5kWh of energy capacity, the Powerwall can sustain your home in the instance of a power outage. If used in conjunction with an effective solar power system it can supply your home with power indefinitely. Keeping the lights on long after you would have been plunged into darkness.

Time-of-use load-shifting

Following a similar theory to pumped-storage hydroelectricity, you can use your Powerwall to directly shrink your energy bill. Provided your utility provider operates a load-shifting scheme you can charge your battery from the grid when power is at its cheapest, typically during the night, and then use it when prices are at their peak, dramatically reducing your overall energy costs.

So whether you'd prefer to save your energy for an emergency or use it for powering your home after sunset, you can control the consumption settings of your Powerwall on the specific app. 

The Stats

  • Weight: 125kg 
  • Dimensions: 1150mm x 753mm x 147mm
  • AC Voltage: 120/240 V
  • Capacity: 14kWh
  • Maximum Power Discharge: 7kW (short term)
  • Typical Power Discharge: 5kW
  • Efficiency: 90%, at the start of usage
  • Noise: < 40 dBA
  • Mounting: Either floor or wall 

Why Buy A Powerwall?

home solar power The Tesla Powerwall: Explained

  1. Reduce your energy bills: By extending the usability of your solar panels you will no longer have to buy energy from the grid during the night. If used in conjunction with load-shifting you can reduce your energy costs further, even if it’s cloudy.
  2. Go fully solar: By extending its use throughout the night, reducing your carbon footprint. 
  3. Safety: Designed to be self-contained Powerwalls have no exposed wiring nor any external heat vents, making it both pet and child-friendly, unlike many traditional battery solutions.
  4. Power outage insurance: The Powerwall 2’s capacity of 14kWh can provide power for the average household for roughly a day and a half (based on UK figures), even if the power grid goes down you can carry on as normal. 
  5. Monitor your energy use: Powerwall’s integration with Tesla’s app gives you complete control over your energy, shifting between different modes (self-powered, back-up only, and load-shifting). The app even allows users to set the percentage of the battery’s output to be used as a back-up and view exactly where their power is going. 
  6. Appearances: Renowned for stylish, elegant products Tesla maintains this trend with the Powerwall with its sleek, minimalist design. And, even if you don’t want it in the house it is weatherproof and can easily be installed outside instead.
  7. Longevity: Tesla guarantees that every Powerwall will retain 80% of its capacity over 10 years (based on the UK warranty), giving users peace of mind that their investment will last.

How much does the Powerwall cost? 

As is typical with game-changing tech, the Powerwall is not a small investment, we’ve broken down the pricing so you can decide whether it’s worth it:

  • Base Unit Cost: $7,500
  • Additional Required Hardware: $1,000
  • Installation: $3,500
  • Total Costs: $12,000

This cost doesn’t include a solar power system, with a Medium system from Tesla costing $11,840 ($16,000 without Federal Tax Credits).

Is the Powerwall the right option for me?

Tesla only offers the Powerwall with a capacity of 13.5kWh, limiting the options for those who live in smaller, more energy-efficient households. 

While 13.5kWh is enough to power the average UK home for roughly 2 days, many homeowners will question the need for such capacity when blackouts are few and far between, and typically do not last more than a few hours.

Yet for those who live in larger households, charge electric vehicles, or generally have higher energy needs you can combine up to 10 Powerwalls, which would provide an enormous 135kWh storage. However, Tesla recommends just one Powerwall for the average home. 

Also, those who will see the most benefits are those who live in areas with high energy prices, as they will recoup their costs far faster than those with access to cheaper energy. 

Some estimates place the payback period (how long it takes to equal the cost in savings) between 8-10 years, however, the cheaper the energy prices the longer this payback period will be, potentially pushing it far beyond Powerwall’s 10-year warranty.

Tesla The Tesla Powerwall: ExplainedWhere Can You Buy One?

You can reserve and order a Powerwall on Tesla’s website, which provides a customised estimate based on your power requirements. 

At present, you can only purchase a Powerwall directly from Tesla, who has been struggling to match supply with increasing demand. However, the company has partnered with local professionals, accrediting them as Tesla Certified Installers, to increase the speed at which you can get a Powerwall into your home. 

Tesla has also provided a service to find accredited installers near to where you live.

Alternatives to the Tesla Powerwall

Tesla’s Powerwall is by no means the only power storage option available, with LG, Sonnen, and Powervault all offering comparable products with a variety of capacities and price ranges. While Tesla is making waves in the industry it is important to remember that they are not the only, or indeed the best, option. 

Is the Powerwall worth it?

Tesla’s Powerwall is a potential game-changer for homeowners with solar power systems, extending usability throughout the night and providing a backup power source in the case of a blackout. 

With the potential to save on electricity bills and reduce carbon emissions they can make a wise investment in a time with increasing energy costs and the rising risks associated with climate change. 

However, a Powerwall isn’t cheap, setting buyers back well over $10,000, and therefore should not be purchased on a whim. It is important to consider energy prices and other options on the market, as there are many. 

Yet, there is a great potential associated with Tesla’s Powerwall, which may receive new features in future years with Tesla regularly providing software updates.

How many Tesla Powerwalls do I need?

The number of Powerwalls needed to power your home largely depends on the amount of power required. Smaller homes can get by with 1 Powerwall, whilst homes with larger appliances may require 2-3. 

How long does a Tesla Powerwall last?

Tesla guarantees that every Powerwall will retain 80% of its capacity over 10 years (based on the UK warranty), giving users peace of mind that their investment will last.

How long does it take to charge a Tesla Powerwall?

In optimal conditions (around 8kW of solar power) and no loads, the Powerwall could be charged in under 2 hours. Charging times vary depending on the weather conditions and if the Powerwall is being used at the same time.

What type of battery is the Tesla Powerwall?

The Tesla Powerwall 2 battery is a Lithium NMC (Nickel Manganese Cobalt) and has double the capacity and triple the power output of its predecessor in the Powerwall 1. 

How much is a Tesla Powerwall?

Cost varies per case but a general estimate is $12,000. This price does not include a solar power system that can begin at $11,000.

How many solar panels does the Powerwall require?

Number of solar panels required is worked out on a case by case basis.

In some instances, only one solar panel is required but for the majority it is around 20. 

Can I use a Tesla Powerwall to go off-grid?

The short answer: yes. The long answer: is it really a good idea? Whilst it is possible to go off-grid with the Powerwall, the costs associated may put some people off. In most cases, it is more cost-effective to remain on the grid with your own solar and battery solution. 

Will there be a Tesla Powerwall 3?

Tesla currently has no plans to develop or produce a Powerwall 3. Demands for Powerwall 2 are already high that waitlists have been formed. 

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