Power2Switch was at an event at the U of I Urbana Champagne a few weeks ago. They have a pretty good looking campus! We were meeting with students as part of the Mayor’s push to keep engineering students from Chicagoland colleges in Chicago, post-graduation, instead of losing them to jobs on the coasts. As is expected with events catered towards broke undergrads, there was free food and drinks as well as a few freebies from the companies that attended the event. We came prepared with the typical startup swag, t-shirts.
Since t-shirts are our go-to swag at these types of events, it got me thinking about how much energy goes into making a t-shirt. Then I thought, “that’s too lame”, let’s take it a step further… how much energy does a woman need to make an XL large t-shirt? So I did some digging and am sharing what I learned below. All I can say is thank God for technology
The process for manufacturing a plain cotton t-shirt (we’ll say an XL one?) involves:
Step 1: Cottonseeds are planted and it takes about 100 days between planting and harvesting.
- Energy use assumption with the proxy being gardening= 191 Cal
Step 2: The cotton is harvested from the cotton farm
- Energy use assumption with proxy being butchering an animal = 229 Cal
Step 3: The Cotton is shipped to a gin and pressed into bales
Step 4: The cotton is spun into sheets of fabric
- Energy use assumption with the proxy being carrying a small child = 114 Cal
Step 5: The Cotton is woven into sheets of fabric
- Energy use assumption proxy is hand rolling in a steel mill = 305 Cal
Step 6: The cotton is wet processed, dyes are rinsed off and the fabric is made smoother and softer
- Energy use assumption (proxy is operating a press punch)= 191 Cal
Step 7: Finished cloth is sent to the garment factory for cutting and stitching, machine processed.
- Energy use assumption with proxy being doing carpentry = 114 Cal
Step 8: T-Shirt is shipped to store where you go in to purchase. Or if you use Threadless.com then it probably comes to you from the warehouse/funky office here in the West Loop in Chicago
- Energy use assumption with the proxy being mountain biking = 324 cal
Methodology: convert calories to Joules, then Joules to kWh and kWh to dollars (whew look at that math!)
Total Calories used for all these activities = 1556 Cal
Total Joules used for all these activities = 6510304 J
Total kWh used for all these activities = 1.808kWh
In Chicago a kWh is 5.1c/kWh. So the whopping total cost for the energy used to manufacture that t-shirt you have on is 9.2cents!! We hope you didn’t pay too much for that t-shirt because most of what you paid is just money in the pocket of the company that branded it…
Note 1: All energy assumptions courtesy of Wolfram Alpha
Note 2: This is not meant to be a scientifically accurate post. The joke is on you if you thought it was after reading all this way.