I got an email from AT&T today: Turn your iPhone green with a new ZERO Charger

Now you can remain powered, without wasting power. With an exclusive built-in switch, the AT&T ZERO Charger makes sure that if you’re not charging your phone, you’re not using any power.

Plus, the AT&T ZERO Charger works with other small USB chargeable devices, including other mobile devices, so you can travel more lightly.

Well, I was intrigued! Okay, not really, as I have a pretty good understanding of how much power my iPhone charger really is using when not in use, but I clicked through to AT&T’s accessories web page and clicked through to the ZERO charger to see how much it would cost me to reduce my iPhone’s carbon footprint.

Cost of the charger: $12.00. ($18.00 if I wanted the kit with the additional micro-USB Charging cable.) Note: this cost is 40% off the regular price (limited time only!)

I selected the lower-priced model, clicked through to my shopping cart and calculated my taxes. Depending on whether I select free shipping or overnight shipping the cost ranges between $12.85 and $28.86

Alrighty then. There is my starting point. I can pay $12.85 – $28.86 for a “green” charger to replace the energy sucking charger I already own.

Well, I had to figure it out. Is the energy savings worth coughing up $12.00 (plus tax), not to mention the additional energy cost of the UPS truck bringing it to my door? Let’s see!

Let’s take a look at the costs I would actually incur by purchasing this device vs keeping my current iPhone charger. The costs I am about to calculate do not take into consideration the cost of manufacturing, nor the travel costs incurred in getting the device to market as I am only trying to determine if purchasing this device will (A) reduce MY personal carbon footprint and (B) save me money on my electric bill.

Transportation costs:

The UPS driver comes through our town every day, but doesn’t have to make the detour to our house off the main highway unless she’s bringing us something, so I will only count the additional energy cost incurred in making a delivery to our house. After all, it’s my fault the truck is using the extra gas, so in fairness, that cost of the carbon footprint should go to me. Our house is located about 2.5 miles off the main highway, making the trip back and forth approximately 5 miles. I don’t know if they make up the entire UPS fleet, but assuming that the fuel efficient hybrid van is the one used on our route, at 13.1 mpg (chart), and with diesel prices in Reno hovering around $3.00 per gallon, it costs UPS 23¢ per mile to make the jog over to our house. Cost to transport to our front door: $1.15

So far the cost to me in dollars: $14.00 (using the free shipping option).

Energy Savings

We’ve all heard the story about how much energy our appliances supposedly use when they are in “stand-by” mode. The coffee-maker, the microwave, the toaster, even down to our camera and phone chargers. You get the picture. Based on the hands-on research done by Digital Bits Skeptic Andy Kaiser, there appears to be a lot of misinformation as to how much electricity our appliances really are drawing.

Okay. So, how much ‘phantom power’ is my iPhone charger actually sucking out of the grid when it isn’t charging my phone? And what is “phantom energy” anyway? How much money will I save by purchasing this charger? This Slate article about the energy wasted when leaving your cell phone in the charger overnight says:

Let’s start with the most ubiquitous mobile device—the cell phone. What happens if you leave yours plugged in all night? According to measurements from Lawrence Berkeley National Laboratory, the average cell phone draws 3.68 watts of power from the outlet while it’s charging and 2.24 watts when charged. Let’s take the worst-case scenario and assume that you’re over-juicing a charged battery for the entire night. Leave the average phone plugged in for eight unnecessary hours, and it’ll use about 0.018 kilowatt-hours of electricity. Do that every night for a week, and the figure rises to 0.13 kWh; every night for a year, and you’re looking at a grand total of 6.5 kWh of electricity.

A quick perusal of my last electric bill shows an average cost of 12.6¢ per kilowatt. So at the rate expressed above, leaving my iPhone in the charger every night (I don’t) would cost me 82¢ (6.5 x 12.6¢) over the course of a year. I assume the cost would be the same for the ZERO™ Charger. So, I’d still be out the 12.85 and UPS would still be out the $1.15. A wash.

My next question is, how much energy is being drawn by my charger when I’m NOT using it, but leaving it plugged in?

What if you leave your phone charger plugged in all the time, even when the phone itself isn’t attached—how much vampire power would that suck up? Again using the Berkeley Lab figures, if the average charger is plugged in for the entire 8,760 hours of the year, it’ll use about 2.3 kWh of electricity. As Cambridge professor David MacKay notes in his book Sustainable Energy—Without the Hot Air, obsessively unplugging your charger is like “bailing the Titanic with a teaspoon.” By all means, do it, he says, “but please be aware how tiny a gesture it is.” (He goes on to note that, according to his calculations, keeping your phone charger unplugged for a year saves as much energy as skipping a single hot bath.)

2.3kWH x 12.6¢ per kWH = 29¢ for one year. Well, damn! At an initial cost of $12.85, my ZERO™ Charger would start paying for itself in 44 years if I never used the charger but just left it plugged in on “stand-by.” And that’s all the savings the makers of the ZERO™ Charger promise me. They do not promise to lower my current charging costs. Those charges, I assume, remain the same. So, assuming that I’m charging 8 hours every day of the year, and leaving the charger plugged in the other 16 hours (2/3) of the day, my current Total Cost Per Year for using a charger plugged into the wall at all times is $1.01 based on a calculation of 82¢ + 19¢ (19¢ being 2/3 of 29¢).

And none of these calculations took into consideration the cost of manufacturing and transportation costs of this “feel good, do nothing” device.

Furthermore, by tossing my still functioning chargers, won’t I be wasting the energy it took to manufacture and transport my still-functioning charger?

What do I do with the charger I no longer need? Where will it go? To a place like this?

There are better ways to reduce your carbon footprint. Slate again:

Given that the average American’s residential electricity consumption is more than 4,000 kWh each year (PDF), the Lantern doesn’t think that a handful of kilowatt-hours are worth much tossing and turning. You could do way more for the planet, for example, by swapping out a single incandescent light bulb in your home for a compact fluorescent one; as the Lantern pointed out in a previous column, that simple action alone can save 126 kWh a year.

A pack of three at Home Depot will cost you about $9.50. Go for it.

Originally posted at Blue Lyon