Saturday, July 17, 2010

How Much Energy Do Avatars Consume?

You sure?
Location: Air-Conditioned Room

It's HOT and sweaty here at my latitude, so even an early morning bike ride to the farmer's market meant lots of sweat. That type of climate means staying indoors more, and that means more time online.

There's long been a meme transmitted online about how much energy Second Life's servers and client computers use. While doing some other work, I stumbled upon this article written by Daniel Pargman on Feb. 10 and republished at The Post Carbon Institute's Energy Bulletin.

For a Peak-Oil guy like me, this was the best of all possible worlds! Pargman did some decent mathematical analysis. A few findings follow:
  • A computer at work uses 120-150 watts, but a computer that runs Second Life (or World of Warcraft or any other computer games) can use up to twice as much power as these applications make use of your computer's capabilities to the max. Data center use a lot of power, but you home computer that utilizes these services draw a lot more and get less work (computer cycles) done per unit of energy used.
  • It is difficult to determine the usefulness (or damage) of using virtual worlds. On the one hand, you use a lot less energy (and generate considerably less pollution) if you cancel a trip and instead meet in a virtual world. But a computer uses a lot of electricity - if the option is an electricity-free activity (take a walk, talk to a neighbor, help your children do their homework).
  • (Based on 30K concurrency in SL and 240,000 kWh to run 2000 servers) In total, [this figure] divided into 30 000 avatars becomes 6.8 kWh per day. That is equivalent to 2 500 kWh per year and the home computer accounts for almost 90% of the total power consumption. Latvia, Romania and Argentina are a few countries that had a power consumption in the neighborhood of 2 500 kWh per capita in 2005. In Sweden, we used more than 15 000 kWh per person in 2005.
Pargman published his analysis in part to update Nick Carr's often cited claim that a Second Life avatar uses as much energy annually as does a typical Brazilian. Carr made his claim when concurrency was at 15,000 and the calculation, later corrected, that Linden Lab ran 4,000 servers.

The best shot by Pargman at this weak claim follows, "

no real person is connected to Second Life 24 hours a day and that Second Life actually had 700 000 "active user" (whatever that means) at the time. So the power consumption of each person who used Second Life would have been just a 50th of Nick’s original calculation. Furthermore, any computer that is used for 24 hours a day 365 days per year uses more energy than the average Brazilians whatever that computer is used for (playing Second Life or doing something entirely different). 


As for this Second Lifer, I'd be reading a book or doing some writing, like this blog, if not logged into a virtual world. And today the AC would be on full-blast.

So the environmental impact of our fun may be moot, as long as the population using processor-intensive applications like virtual-world clients remains small.


Peter Miller said...

FJ Linden had a blog on the general topic of energy-saving and it pointed at this. There are some numbers in the small print but I can't for the life of me find the overall figure they are supposed to be qualifying. Anyways, a third less again would still be good news.

Iggy O said...

Thanks, Peter. I guess we'll only know we're using too much energy for SL when the lights begin to dim at login.