Is a hosted app more Green than hosting your own? Is Software as a Service (SaaS) more environmentally than the more traditional models?
I contacted a number of SaaS vendors (who, admittedly, may have a vested interest in this!) but the answers were a resounding yes.
Chris Yeh, for example, from PBWiki did some quick back of the envelop calculations and replied with:
PBwiki hosts 500,000+ wikis on a total of 20 servers
If a server consumes 200 watts of power, that’s 1.75 megawatt hours/server/year (200*24*365)
According to Sun’s Dave Douglas (http://www.roughtype.com/archives/2006/12/avatars_consume.php), that’s the equivalent of 1.17 tons of carbon dioxide per year, or driving an SUV 2,300 miles
That means PBwiki could be saving the world up to 585,000 tons of carbon dioxide per year, or the equivalent of driving an SUV around the world 50,000 times!
Now, obviously not all 500,000 hosted PBWiki’s are replacing an individual server but say 100 PBWikis replaces one server, or 1,000. That’s still somewhere between 600 and 6,000 tons of CO2 PBWiki are saving the planet per annum.
Anyone got harder numbers than that around the energy efficiency of SaaS?