WSJ has a blog post on The Green Side of Shopping.
The Green Side of Online Shopping
E-commerce reduces the environmental impact of shopping by using about a third less energy than traditional retail — but only if you skip the express airmail.
A study out Tuesday by the Carnegie Mellon Green Design Institute offers a scientifically rigorous estimate of e-commerce’s green benefits. E-commerce not only uses less energy, but its carbon footprint is also a third smaller than bricks-and-mortar retail, the scientists found.
Lead researcher H. Scott Matthews and his team compared the energy consumption and carbon dioxide emissions required to deliver a small flash drive to a shopper via a trip to a traditional store versus buying and shipping the flash drive via Buy.com.
The methodology used:
Coming up with these calculations required many assumptions by the scientists – but they’re a lot more informed than past attempts to account for the environmental benefits of e-commerce, say the researchers. That’s because the e-commerce site Buy.com made available to them information about its data center, last mile delivery practices and other sources of energy consumption. (Buy.com is a member of the Green Design Institute’s Corporate Consortium, but didn’t pay for or direct the study.)
The scientists found that by far the largest environmental cost of traditional shopping is a consumer driving his or her own car to a store. (They assumed that the average person drives about 14 miles round-trip per shopping outing, and buys about three different items on one trip.)
Much of the energy expenditure for e-commerce also goes towards last-mile delivery. But a UPS truck delivering dozens of packages along its daily route uses a less energy per package, on average. That’s where e-commerce really shines.
What about the data center?
Data centers and computers, it turns out, are a relatively small energy cost for e-commerce.
The results based on data from Buy.com can’t necessarily be extrapolated to other e-commerce sites such as Amazon.com, warn the scientists. That’s because Buy.com operates with an unusual virtual model in which products are shipped directly from distribution partners to customers, eliminating a step in the supply chain that many other e-commerce companies still use.