What is Tesla Powerwall?
Elon Musk thinks you’ll get a charge out of his latest product: the Tesla Powerwall, a wall-mounted battery that stores up to 10 kiloWatt-hours of electricity. Musk calls it “the missing piece” in the puzzle of how to wean ourselves off dependency on fossil fuels and power grids. Here's what you need to know...
Fire the Utility Company?
The Sun generates all the power humanity needs (which Musk estimates at 90,000 gigaWatt-hours annually). Enough solar panels to supply all of humanity’s needs would take up no more than half of New Jersey. Most of those solar panels would be mounted on existing rooftops and take up no additional acreage at all.
But the Sun does not shine all the time, or even with equal strength all the time. Therefore, electric power generation by solar panels is uneven and often unavailable. We need batteries to store surplus solar electricity until it’s needed. Big batteries aren’t cheap, as anyone who owns a boat or solar-powered home knows. Batteries are bulky and ugly; most homes that have gone off-grid include an entire room just for battery and related gear, or even an outdoor shed.
The Powerwall introduced by Tesla Energy puts everything you need (except a DC/AC inverter) into a relatively stylish package about the size of a 50-inch flat-screen TV. It’s designed to be hung on a wall, even an exterior wall. Up to nine PowerWalls can be “stacked” for additional storage.
A single Powerwall stores up to 7 kWh or 10 kWh of electricity; prices, excluding installation, are $3,000 and $3,500, respectively. (Costs may be lowered by local subsidies from governments and utility companies.) In 2013, the average U. S. household used about 30 kWh of electricity per day. Power consumption varies widely by region; Louisiana’s average is more than twice that of Hawaii. Household habits also play a role in electricity consumption.
A single Powerwall might well get the average household through the night, unless it’s one of those nights when everyone needs space heaters. Up to 9 Powerwalls may be desirable if you want to go fully off-grid or if lengthy power outages are common in your area.
Figuring the Total Costs
At $350 per kWh, the 10 kWh Powerwall beats the leading competition handily. A January, 2015, report from Moody’s pegs the average cost of batteries at $500 to $600 per kWh https://www.moodys.com/research/Moodys-Despite-falling-battery-costs-consumers-unlikely-to-defect-from--PR_315969. But in addition to the PowerWall, you need a DC/AC inverter, and professional installation of the system, which adds $5000 to $7000 to your total cost.
And that assumes you're feeding the PowerWall from the electric grid, for use as a battery backup during brief power outages, or to take advantage of "price-shifting" in areas where electricity is cheaper at night. If you want to use a PowerWall to go off-grid, you'll need to spend another $20-$30K on a solar system.
Is the Powerwall “just another toy for rich green people,” as Forbes’ Christopher Helman asks? http://www.forbes.com/sites/christopherhelman/2015/05/01/why-teslas-powerwall-is-just-another-toy-for-rich-green-people/ His analysis, which includes the cost of the DC/AC converter needed for home use, and the cost of supplying energy to the PowerWall (it only stores power, it doesn't generate) indicates that it probably doesn't make financial sense, unless you already have a solar panel system large enough to power your home.
But powering homes is not the end of Musk’s ambition. Tesla Energy is also working on the PowerPack, a more cubic battery that will store up to 100 kWh of power. It’s intended for utilities and large users such as Amazon, Walmart, or Google. Of course, Tesla won’t rest until every vehicle in the world runs on batteries.
I suspect many readers have at least experimented with solar power and battery storage systems. Your thoughts on these subjects in general, and the Powerwall, are welcome. Post your comment or question below...
This article was posted by Bob Rankin on 14 May 2015
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Article information: AskBobRankin -- What is Tesla Powerwall? (Posted: 14 May 2015)
Copyright © 2005 - Bob Rankin - All Rights Reserved