Nicholas Carr has written a fascinating post on a subject I've been thinking about recently:
If there are on average between 10,000 and 15,000 avatars "living" in Second Life at any point, that means the world has a population of about 12,500. Supporting those 12,500 avatars requires 4,000 servers as well as the 12,500 PCs the avatars' physical alter egos are using. Conservatively, a PC consumes 120 watts and a server consumes 200 watts. Throw in another 50 watts per server for data-center air conditioning. So, on a daily basis, overall Second Life power consumption equals:
(4,000 x 250 x 24) (12,500 x 120 x 24) = 60,000,000 watt-hours or 60,000 kilowatt-hours
Per capita, that's:
60,000 / 12,500 = 4.8 kWh
Which, annualized, gives us 1,752 kWh. So an avatar consumes 1,752 kWh per year. By comparison, the average human, on a worldwide basis, consumes 2,436 kWh per year. So there you have it: an avatar consumes a bit less energy than a real person, though they're in the same ballpark.
That's a lot of additional energy use for those that sit around in Second Life earning Lindens to gamble in the casino. It's only 12,000 people out of the 6 billion inhabitants of planet Earth so I don't see it as a dramatic cause for concern.
However, one thing that does cause me concern is those server numbers... 4000 servers for 12,500 avatars? Is it just me or does the thought of one server supporting only 3 avatars send shivers down your spine too?