For small businesses, using a web-based email service can eliminate the headaches associated with operating your own email server. It can also be better for the environment, according to Google, which has released a case study outlining the energy and carbon savings from using its Gmail service. In fact, Google argues, the scale of its highly-optimized data centers makes Gmail substantially more energy efficient than all but the most advanced corporate data centers.
It's not surprising that Google makes a business case for the cloud computing model. But the case study, Google's Green Computing: Efficiency at Scale (PDF), offers estimates on the per-user energy required to deliver email in several infrastructure scenarios.
"Our size, focus, and ability to optimize across barriers translates into a series of distinct advantages for our servers hosting cloud-based email," Google writes. "Optimizing the entire process of storing, hosting and serving email means that Gmail requires less than 250 mW per user. Over the course of a year, that’s just a bit more than 2 kWh of energy, or about $0.22 per user per year, representing significant savings over the locally hosted alternatives."
The most compelling differences in energy usage are seen in comparisons between Google's infrastructure and small business servers. But the energy savings are still substantial when compared to data centers running at a Power Usage Effectiveness (PUE) of 1.6, well below the average of 1.9.
Of course, cost and reliability are the primary metrics for companies considering whether to outsource their email. For those looking at the next tier of decision points, the Google study offers some useful data.