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Friday, June 22, 2012

How Much Would You Pay to Charge Your iPad?

Posted by on Fri, Jun 22, 2012 at 7:55 AM

Would you believe less than a penny a day?

Consumers who fully charge their iPad tablet every other day can expect to pay $1.36 for the electricity needed annually to power the device, according to an assessment by the Electric Power Research Institute (EPRI).

The analysis shows that each model of the iPad consumes less than 12 kWh of elelctricity over the course of a year, based on a full charge every other day. By comparison, a plasma 42” television consumes 358 kWh of electricity a year. ... The EPRI analysis shows that the Apple iPhone 3G consumes 2.2 kWh of electricity each year, which results in a power cost of $.25 annually.

Other products that were included in the analysis were laptop PCs, which consume 72.3 kWh of electricity each year and cost consumers $8.31 and 60W CFL light bulbs which consume approximately 14 kWh of electricity and cost consumers $1.61 a year.

I hadn't thought of it much before, but one of the benefits of consumers' massive shift toward mobile computing is the decreased power consumption of battery powered devices that are energy efficient by necessity. Laptop PCs are more efficient than desktops, and as this EPRI study shows, tablet devices like the iPad use one sixth of the energy of your average laptop, while smartphones burn even a fraction of that.

Individually the power/money saved doesn't look like all that much compared to the hardware and network costs of the devices, but collectively even a modest shift of usage from traditional PCs to low-power mobile devices can add up to a substantial reduction in global energy consumption.


Comments (16) RSS

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Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn 1
iPads do less computing. They don't do the kind of number crunching involved playing decent games, or in the use of a computer to do actual work. Processing consumes power. It's hard to even write a decent amount of text on something without a real keyboard.

But yeah, for people who weren't using their desktops and laptops for anything but reading the web in the first place, it makes sense to cut out all that processing and just keep a screen for them to look at.

(Also. I know tons of people who traded their 42" plasma TVs for iPads. Great comparison there.)
Posted by Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn on June 22, 2012 at 8:23 AM · Report this
Dr_Awesome 2
Wait, wait, hold on a second.

You mooching hippies are only trying to justify this latest "fad" of yours where you steal my electricity out of the receptacles you find hidden in Our Fair City.

See this lawn? It's my lawn. Now get off, dad-gum'it!
Posted by Dr_Awesome on June 22, 2012 at 8:32 AM · Report this
The growth of low-power consumer devices is enabled by the growth of massive, but unseen, server fleets that suck down entire hydro dams worth of power. You can do more with a less-powerful device in your pocket if the heavy lifting is moved to the data center. Don't know what the net outcome is, power-wise, but it's not simple.
Posted by shabadoo on June 22, 2012 at 8:41 AM · Report this
@3 makes a good point -- All of us use huge rooms of powerful computers every day, just not directly. It doesn't cost a lot of energy to hook up a browser and look at something a computer far away generated.

Also, the lithium batteries that go inside these devices have a very heavy ecological footprint in a materials and energy sense.

A great point that this post makes is that phones use such small amounts of electricity that you should never worry about whether it's plugged in overnight. You're saving nothing by being careful about how long the charger is on. This same point was made by David MacKay in a book about sustainable energy that everyone should read:
Posted by ScruffyBallardMan on June 22, 2012 at 8:57 AM · Report this
rob! 5
What @3 said. The old corded wall phones were pretty damned energy-efficient too.

It's the cumulative effect of billions of smartphones, iPads, laptops, etc. and the demand their "retina" screens produce for all kinds of plug-in appliances worldwide, beyond the fan, b&w tv, and maybe refrigerator that used to comprise "luxury" goods in much of the world.

China is still firing up at least one new coal-powered generating station every week.
Posted by rob! on June 22, 2012 at 9:07 AM · Report this
briantrice 6
@3 This.

That said, those server fleets are run extremely professionally at much lower overhead (Facebook and Google have each published "green" data center specs for others to use). On the other hand, ISPs and mobile telcos are also sucking down some power to get those iPads connected to them. Not huge, but there's some displacement.
Posted by briantrice on June 22, 2012 at 9:33 AM · Report this
Looking For a Better Read 7
My iPhone uses so little power each day because the fucking battery capacity is so small. Damn thing runs down within 8 hours, without any major stresses put on it.
Posted by Looking For a Better Read on June 22, 2012 at 9:48 AM · Report this

Speaking of iPads:
A daughter is visiting her father and asks: "Tell me dad, how are you managing with the new I-Pad we gave you for your birthday?" (It's in German but you'll get it.)
Posted by onalki on June 22, 2012 at 9:51 AM · Report this
Will in Seattle 9
Actually, our electricity rates are much lower than the rest of the country, because almost all of our power comes from Hydro not from Coal.

So it's more like 10 to 20 cents a day max.

Now, your fridge and dryer, those suck up power like hotcakes.
Posted by Will in Seattle on June 22, 2012 at 10:30 AM · Report this
Westlake, son! 10
Keep pumping your AAPL stock, I'll wait.
Posted by Westlake, son! on June 22, 2012 at 10:55 AM · Report this
prompt 11
@9 Citation needed. I'm guessing you've never heard of Colstrip.
Posted by prompt on June 22, 2012 at 11:01 AM · Report this
rob! 12
Another WiS reading-comprehension fail.

"So it's more like 10 to 20 cents a day max."

Which would be how much per year, Will?

"I'm not gonna do your math for you."
Posted by rob! on June 22, 2012 at 11:05 AM · Report this
Horse shit.

A huge portion of the population want's to have, or already has, a tablet, a smart phone, an mp3 player, an Xbox, a desktop compter, a big screen TV AND a laptop. And they will have a dozen or more of each through out their life times. It's unprecedented consumption. And it's driving MORE energy usage not less.

There is no "shift" to mobil devices. It's just one more thing to consume.
Posted by tkc on June 22, 2012 at 11:36 AM · Report this
I've seen a few paid charging stations at airports--I think there's one at Seatac--that charge ~ $5 for 30 minutes. Thankfully I've yet to actually see one in use, so at least people recognize what a ripoff they are.
Posted by ryanmm on June 22, 2012 at 1:06 PM · Report this
Catalina Vel-DuRay 15
I think one of the benefits of moving the processing load to the server farms is that it is a lot easier to implement energy efficiency on a server farm than it is to try to get people to conserve.

It's sort of like electric cars. People get all puffy about how you are just moving from gasoline to coal, but if the cars are charged at night, that makes the power plant much more efficient. Also, it's much easier to control emissions from one central point - a power plant - than it is from a million tailpipes.
Posted by Catalina Vel-DuRay on June 22, 2012 at 3:18 PM · Report this
Wait! A 60-Watt equivalent (12-15W actual) CFL costs $1.61/year, but a 15-20W (typical) laptop costs $8.31/year?

Must be some unstated assumptions in play - but the press release contained no link to the study itself.
Posted by RonK, Seattle on June 23, 2012 at 12:19 PM · Report this

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