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The "Power" of Information

June 27, 2009 23:58 by author

Let me quickly explain how many of my blog posts come to be. I spend about an hour a day on the web. In that hour I read a lot. During that time I often read statements that just stick in my head for some reason. I don't quite know what's wrong with them at the time, just that something is.

Then I'm off to do research. Scouring the web to find anything that supports or refutes my theory. A lot of this is waisted time. I'm not right anywhere near as much as I'd like to be. But occasionally I am right and that's when you get posts like the one below.

I've mentioned before that I'm a fan of Video Blogger Brigitte Dale and in her latest video she gave an "I love the Earth" tip which was that buying vintage clothes was one of the best and most obvious forms of recycling there is.

And it stuck in my head.

So what I did was to take your average Walmart shirt (made in Mexico) and put it against a used one ordered from eBay. If you don’t care about the calculations and want to just trust me...well...you’re probably a little too trusting. But if that’s you the conclusion to all this is in the last paragraph.

And off we go...

Two caveats before I start. First, these are rough numbers and hence probably give a slightly inaccurate picture. That said, I think it’s as close as someone with no ability to get the exact numbers can get. Second, I’m completely disregarding inter-country travel. The logic is a UPS package is picked up then UPS finds the most efficient way to get it across the country. A WalMart product is driven to their warehouse at which point they also find the most efficient way to get it across the country. If anything this assumption benefits the eBay shipped UPS package because UPS is under a deadline so they have to fly most packages (huge carbon footprint) while Walmart can use trucks or trains (much smaller carbon footprint)

OK then…

Obviously the miles driven to pick up and to drop off an eBay purchase vary. So I’ll use UPS averages to get an idea instead. A UPS truck produces 984.8 grams of CO2 for every mile it drives. It took the linked to driver (see last sentence) 22 years to drive 1,000,000 miles which means about 174 miles a day. The average UPS driver delivers about 163 packages a day. So from that we can get a rough number of 1.07 miles per package which means 1,053.7 g of co2 per package (984.8 * 1.07).

Compare that to creating a shirt. Cotton production requires a Cotton Picker and a Gin Mill.

This site gives us an energy calculation for using a sweep tractor (essentially what a cotton picker is) putting it at around .60 gallons per acre. Now a gallon of Diesel produces 2,778g of co2 so .60 gallons of Diesel produces 1,666.8g of co2 per acre. An acre produces about 740lbs of cotton which equals 11,840 oz per acre. A cotton t-shirt is about 6oz . Meaning you can get about 1,973 shirts out of one acre of cotton. 1,666.8g of co2 per acre divided by 1,973 shirts per acre equals .84g of co2 per shirt.

Now to the sweat shop. A sewing machine takes .2kWh per hour . That’s .0033kWh per minute. A clothing worker can produce a shirt in about 3 minutes meaning .01kWh per shirt.

Now Mexico’s electricity is produced largely by Natural Gas at this point and 1 kWh of natural gas produces 204.5 g of CO2. Multiply our .01kWh of sewing by 204.5g of co2 from natural gas and you get 2.045g of co2 per shirt.

(For the record sweatshop labor is wrong. But numbers are still numbers)

Now yes, the new shirt has to be delivered to the Walmart warehouse and that is done on diesel engine trucks. But keep in mind those shirts are driven in by the thousands. So an 18 wheeler can carry one 40’ or two 20’ cargo containers which would give them a cargo hold of 2,261 cubic ft . If you pack shirts tight you can easily get 20 in a cubic foot giving you 45,220 shirts for the cargo hold. That’s at 5.3 miles per gallon which in turn means 1,915.69 g of co2 per mile (10,153 grams per gallon / 5.3miles per gallon). But with the high number of shirts we get .0424g of co2 per mile per shirt.

So even if the truck came from the Mexican border where most of the sweat shops are to a factory in Seattle Washington (the furthest major city going north and unlikely since most warehouses are in the southern U.S.) you’d still only be looking at 190.8g of co2 per shirt for the entire trip (4,500 miles * .0424g per shirt per mile)

(Below is the original last paragraph for those who jumped ahead)

So in the end we get Cotton Production (.84g) + Sewing (2.045g) + Transport (190.8g) for a total co2 footprint of 193.69g of co2 for a new shirt. Compare that to 1,012g of co2 for a used one off eBay.

(The true irony is even if you buy vintage clothes from a store the person who dropped it off there better have driven less than 2 miles to get there. The best selling car in the U.S. at this time last year was the 2008 Toyota Camry which gets 25 miles to the gallon meaning it produces 165g of co2 per mile)

How is this Tech... One of my constant annoyances as a "computer person" is people's misunderstanding of electricity and how much the items in their home or office consume. I am constantly having to remind employees at my agency NOT to turn off their PCs at night because it needs to virus scan, backup, etc... But they think they're "saving electricity". I then have to pull out the ol' chart and explain to them that their toaster uses 9 times the power of a PC and that's while the PC is actively working. Drives me nuts.

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June 28. 2009 11:59

Does seem a little off topic. But interesting. Maybe you should branch out and do Tom's Green Blog.com

Alfred

June 28. 2009 12:22

Har, Har.

For the record this started out as a comment on the aforementioned video blog but became so long that I no longer felt it was appropriate as a comment. But I didn't want the work to go to waste so I put it up here.

So yes, it took a little twisting to make it even remotely tech related.

Tom

June 28. 2009 13:31

One problem I have with this is the calculation for delivering the one shirt. I, like a lot of people have things I ordered online delivered to where I work. UPS truck is constantly delivering things to the building I work in as well as all the surrounding buildings. And they don't just drop packages off, if there are boxes ready to ship out they pick them up rather than waste the gas and time to send another truck to get it. So your calculation for the delivery of the item is based on the driver traveling 1.07 miles per package seems wrong. My office alone gets 15 to 20 boxes a day, we're not in manufacturing just a regular office with a bunch of accountants. We take up less than half a floor in a building with 8 floors. Then add in the two dozen other offices in that one mile stretch of road. If you don't take all this into account then your calculations are wrong.

Joe436

June 28. 2009 14:01

Well, I sincerely doubt someone’s going to have their vintage clothing delivered to the office.  But I see your point.

The problem with your logic is that it offers no way to make the calculation at all.  The truth is every package requires a different distance to be traveled in order to be delivered.  In an office building it might be a few feet but in a rural area it might be a few miles.  But when considering two scenarios in the abstract (as opposed to two ACTUAL packages) we have to deal in generalizations and that means determining what happens in the aggregate and then getting averages from that.

That’s what I did.  By taking what I hope is close to the average number of miles driven by a UPS driver and dividing it by the average number of packages (as provided by UPS) I determined each package on average travels about 1.07 miles total (which is only .535 miles per trip when you consider that entails the picking up and dropping off of the package).  That number will surely be high for some and surely be low for others but in a general sense it’s the most accurate number we can determine to make a comparison.

More to the point my goal here isn’t really to say there’s a bigger carbon footprint in every case but to show people it isn’t an obvious conclusion.  If someone walks away from this with their eyes opened to that fact I’d be overjoyed with the result.

Tom

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About Me

Hi, I’m Tom and I run the IT department for a non-profit agency which provides treatment to special-needs children. Though I will (like any blogger) comment on technology in general my main goal is to detail how I’m trying to use technology to help treat the children we serve and its my hope that blogging will allow me to connect with people who can help in that goal.

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