On a computer the CPU plays a big part in its total energy usage. A modern CPU can easily gobble up between 20-60 watts when in full use. When casually browsing the web, Adobe Flash can often be seen to hog the CPU’s idle cycles by 100%, preventing any of the energy saving technology in CPUs to kick-in. In some browsers this even happens when tabs with Flash are not being used and open in the background…
Ars Technica had a good write-up about this phenomenon in the new MacBook Air a few days ago:
We did find (quite by accident) that Apple may have more reasons behind not installing Flash by default other than the stated reason of ensuring that users always have the most up-to-date version. Having Flash installed can cut battery runtime considerably—as much as 33 percent in our testing. With a handful of websites loaded in Safari, Flash-based ads kept the CPU running far more than seemed necessary, and the best time I recorded with Flash installed was just 4 hours. After deleting Flash, however, the MacBook Air ran for 6:02—with the exact same set of websites reloaded in Safari, and with static ads replacing the CPU-sucking Flash versions.
If you consider these rough numbers, that Flash increases energy usage of a highly efficient laptop by 33%, and you consider the amount of computers in use at any given time, then you can make some fun estimates:
Say that on average 250 million people are browsing the web simultaneously. And say that, about a quarter of the time, some Flash ad is being displayed on one of those machines. Also say that running Flash uses 30 watts on average. Then Flash is wasting 1875 megawatts of energy, enough to power about five million European households. Or the equivalent of the energy produced by 700 typical wind turbines.
Interesting to see such a huge environmental impact from a small piece of software! So do yourself (and the planet) a favor, and remove Flash!
Please correct me if I’m wrong about any of these numbers!