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Shopping Online More Energy Efficient, Say Carnegie Mellon Researchers

A new study out of Carnegie Mellon University finds that shopping online instead of going to a retail store cuts CO2 emissions. The research (PDF), performed by the university's Green Design Institute, found that shopping online via comparison shopping site uses 35 percent less energy consumption and carbon dioxide emissions than what is produced in the traditional retail shopping model.

Researchers compared the energy use and CO2 emissions associated with delivering a flash drive from a manufacturer to a home via the traditional retail channel and's e-commerce channel. The three largest contributors to energy consumption and CO2 emissions include customer transport for traditional retail, packaging, and last mile delivery to customer homes for e-commerce. Approximately 65 percent of total emissions generated by the traditional retail model stemmed from the customer getting to and from the retail store. For e-commerce, packaging and last mile delivery were responsible for approximately 22 percent and 32 percent of the ecommerce energy usage, respectively.

"In a study of this nature with numerous variables, we took great care to estimate average case performance using simulations and approximations," said H. Scott Matthews, associate professor of Civil and Environmental Engineering and Engineering and Public Policy at Carnegie Mellon and research director of the Green Design Institute. "We were able to show that in the majority of cases studied, the e-commerce model does perform better than shopping at traditional retail in the areas of carbon dioxide emissions and energy consumption."

Traditional brick-and-mortar retailers generally have items shipped from distributors to regional warehouses where they are distributed to individual stores before reaching customer homes. In's model products are shipped directly from distribution partners to customers, eliminating one step in the retail supply chain.

Carnegie Mellon researchers found that the traditional retail distribution model, combined with factors such as product packaging and customers driving to and from stores, resulted in greater energy consumption and emissions than in the online shopping model. is a member of the Green Design Institute's corporate consortium.

About the Author

Dian Schaffhauser is a former senior contributing editor for 1105 Media's education publications THE Journal, Campus Technology and Spaces4Learning.

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