Hey guys, I'm Brent Rose, tech writer and gentle assassin.

Elon Musk just announced Tesla's first home battery product.

He thinks it's gonna change the way the world

consumes and stores energy.

Let's break this down so you can sound smart

at your weekend barbecue.

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First off, let's talk about the product itself.

Tesla's Power Wall is basically a big lithium ion battery.

It's about four feet tall, three feet wide,

and seven inches deep.

It looks kind of like the monolith that the monkeys

worshiped in 2001 A Space Odyssey.

Now, Tesla isn't the first company to offer home batteries,

but they're selling it for about a third of the price

of the competitors, and they say it'll last a lot longer.

It comes in two different flavors,

there's a 10 kilowatt hour version for 3,500 bucks,

which is basically used as backup power

in case you have an outage.

Or there's the seven kilowatt hour version for 3,000.

This one's meant for daily cycling, that means

powering up and depleting that power every single day,

running your house off of it basically.

The unit is sleek enough that it can be mounted

to the wall inside your garage

or even an exterior wall on your house.

They can be lined up side by side by side to match

the power requirements of your home.

It also comes in several different colors

in case you want it to match that pretty

Model S you got inside your garage.

Tesla is also gonna be selling an infinitely scalable

hundred kilowatt hour power pack, but that's

just for utility companies and commercial purposes,

so let's leave that aside for today.

So why is this a big deal?

Well, solar energy can obviously only be generated

when the sun is out in the middle of the day.

However, peak energy consumption happens at night

when there's no potential for solar energy.

So all that energy we generate during the day

essentially goes to waste.

What this system does is it gives us a way to store

that energy to then be used later when we turn

the lights on, run the dishwasher, and watch TV.

And if you have enough solar panels, the system has

the potential to take you completely off the grid.

Now, you don't have to have solar panels to use

the Power Wall because you can use

the grid to charge it up, too.

One theoretical benefit could be charging it up

during off peak hours when electricity is cheapest,

and then running your home off of it during

the peak evening hours when electricity prices go up.

That said, given the current price of the batteries,

we just don't see the cost benefit here.

The place where it would make sense is if you lived

in a blackout prone region.

The ability to charge up when you did have power

and then run your home off the batteries when

the grid goes down could be a real life saver.

But what if you used these things plus solar

to get completely off the grid.

How much money could you save?

Well, the average U.S. household uses about 30 kilowatt

hours per day, or just over 10,900 kilowatt hours per year.

So let's say you get four of Tesla's seven kilowatt hour

batteries at 3,000 a piece, that's $12,000

for the batteries alone.

Now the average cost of electricity in the U.S. is roughly

13 cents per kilowatt hour, so you would need to use

roughly 92,300 kilowatt hours before you broke even

on the cost of the batteries.

At the average rate of consumption that's eight and a half

years before this thing pays for itself.

And that doesn't account for the cost of installation,

of maintenance, of the price of an inverter,

which would be thousands, or for the gradual

decreasing efficiency of a lithium ion battery

over the course of its lifetime.

Again, these are just averages, but currently

this is not something that's going to

save most Americans any money.

And that's not even factoring in the cost of solar panels.

That said, if you live in a place where energy

is more expensive, you would break even sooner.

For example, in Hawaii the cost per kilowatt hour

is a whopping 37 cents.

At that rate, it would only take about three years

to recoup the cost of the battery,

which is approaching reasonable.

Ultimately, if you're just trying to save money

then this isn't the way to go yet.

But, if you've got the cash to spend and you live

in a sunny area, then the concept of being able

to live independently of the power grid

has a lot of appeal.

So, what do you think, is this really the beginning

of an energy revolution?

Or is this just Tesla trying to sell more batteries

to justify the existence of it's gigafactory.

Let us know what you think in the comments,

and don't forget to subscribe to Wired.

Thanks for watching.

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