Is Tesla’s Powerwall the Secret to Affordable Solar Energy?

Real life Iron Man and CEO of SpaceX and Tesla Motors, Elon Musk has been synonymous with relentless innovation and progress over the past decade. Musk’s newest project was officially announced on May 1st, and the implications for the energy industry could change the world. I rarely use that phrase, but this just might be the exception.

What is it?

Tesla Energy, a new subdivision of Tesla Motors, has created two separate battery systems: the Powerwall, for residential use, and the Powerpack for businesses and utilities. Little is known about the Powerpack at this early state, but below are a few of the numbers behind the residential-grade Powerwall:

  • Dimensions: 51.2″ x 33.9″ x 7.1″ (wall mounted)
  • Weight: 200 lbs
  • Models/Price: 10 kWh $3,500; 7 kWh $3,000
  • 10-year warranty
  • Power use: 2.0 kW continuous, 3.3 kW peak

New information from Bloomberg indicates that, “for a 10 kilowatt-hour system, customers can prepay $5,000 for a nine-year lease, which includes installation, a maintenance agreement, the electrical inverter, and control systems. Customers can also buy the same system outright for $7,140.”

Per Tesla’s website, deliveries will begin this summer.

Why now?

The impetus for this project stems from society’s over-reliance on fossil fuels and our talent for energy waste. According to the Tesla Energy press kit, “The world currently consumes 20 trillion kWh of energy annually, enough energy to power a single family home for 1.8 billion years … The US electric power sector alone produces over 2,000 million metric tons of CO2, which is like burning 225 billion gallons of gas. The EPA says it would require 1.6 billion acres of US forest to negate the environmental damage.”

Aside from global environmental issues, Tesla believes that the Powerwall will help homeowners financially because the system will automatically begin charging during times of low electricity use (during the day) and discharge during high use periods (at night). By using the stored solar energy rather than additional electricity, money will be saved in the end. Similarly, corporations will benefit from Powerpacks because peak demand charges are avoidable and electricity can be bought at a cheap rate. In addition, utility providers, according to the press kit, will pay organizations participating in grid services like Powerwall. Check out the full, 18-minute keynote, “The Missing Piece,” below:

How Does it work?

According to Musk, Powerwall is like the sun: it “just works.” Thankfully, our friends at ExtremeTech have broken the process down a bit for us laymen: “The Powerwall delivers 5 amps (at 350-400 VDC), 8.5 amps at peak. If you recall high school physics, volts times amps equals watts. For a single Powerwall, Tesla cites 2.0 kW continuous, 3.3 Kw peak … a kilowatt is 1,000 watts and a single 15-amp household AC circuit delivers about 1,800 watts … so you’re getting about one circuit worth of continuous power with the ability for extended periods, and the ability to draw more than 25 amps when the hair dryer or toaster oven kicks in.”

What does this mean? The Powerwall website mentioned above provides the electricity consumption of an average household appliance. One of the items listed is a washing machine, which consumes 3.3 kWh of electricity per use. Essentially, doing one load of clothes drains most of the power out of a single Powerwall unit.

Will it Make a Difference?

Despite the news being extremely recent, various forms of news media are already praising (as well as questioning) Powerwall’s viability. Davide Castelvecchi, of Nature magazine (reprinted in Scientific American), points out that Tesla wasn’t the first company to think of battery-powered energy storage and that the firm has a few competitors; however, these initial units seem slightly cheaper, but not by much. Also, many Western homes do not need supplemental battery power in the home, especially if good connections to the grid are available. Even if your home already uses solar panels, the electrical grid is a battery; Germany and certain American states can buy electricity back at night.

Outside of the residential sector, it is still more efficient for cities and utility firms to use generators. “The US Department of Energy estimates that for energy storage to be competitive, it must not cost much more than $150 per kWh. Assuming a cost of $700 per kWh, Tesla’s systems are still much more expensive than that.” That said, the batteries do make the entire grid more reliable, as it will lessen the burden somewhat during “peak hours.”

No matter how many unanswered questions there are at the moment, however, one thing remains clear: Tesla is one of the few tech companies in America that seems like they are committed to building a better future for everybody, and that includes making all of their patents freely available. No matter how the Powerwall ends up playing out, it’s clear that Tesla is in this for the long haul.

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