I can't find hard data on how many searches are done on google
It's hinted in the article.
with more than 200m internet searches estimated globally daily
Google has an 81% market share. Let's call it 170 million searches per day. 49 grams of CO2 are released per kWh. http://blogsearch.google.com/blogsearch?q=Alex+Wissner-Gross... The article said that Google releases 7 grams per search, so that would be 1/7th of a kWh ~= 0.14 kWh.
Multiplying that by 170m searches/day = 24m kWh/day. At $0.10/kWh, that would be $2.4 million/day, or $886 million/year.
You figured $1 billion/day, but, besides using different assumptions, you incorrectly calculated 1.5 billion searches/day * .7 cents/search/day. It actually equals only $10.5 million/day.
[EDIT] walterk beat me by a minute to that final math correction.
How can there possibly be only 200m searches per day? I must use Google at least a hundred times daily, probably more. There's not even two million people like that already, in the whole Earth?
Google's searches rose 21.7 percent, for 64.1 percent market share, and Yahoo's searches dropped 1.4 percent from November 2007, for 16.1 percent share.
Total searches for the month exceeded 8 billion, up 9.6 percent from a year earlier.
[...]
Correction at 5:50 a.m. Monday: This story had an incorrect total for U.S. searches in November. The total was 12.3 billion.
[...]
Google grabbed a chunk of market share from rival search engines in the United States in November, new figures from ComScore show. [...] The total searches performed dropped 3 percent to 12.3 billion, though, so even Google lost out in absolute terms even as it gained share.
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Dividing by 30 days, that would be 410 million searches per day, in the U.S. For ~200 million internet users, that would be 2 searches per user per day.
It's hinted in the article.
with more than 200m internet searches estimated globally daily
Google has an 81% market share. Let's call it 170 million searches per day. 49 grams of CO2 are released per kWh. http://blogsearch.google.com/blogsearch?q=Alex+Wissner-Gross... The article said that Google releases 7 grams per search, so that would be 1/7th of a kWh ~= 0.14 kWh.
Multiplying that by 170m searches/day = 24m kWh/day. At $0.10/kWh, that would be $2.4 million/day, or $886 million/year.
You figured $1 billion/day, but, besides using different assumptions, you incorrectly calculated 1.5 billion searches/day * .7 cents/search/day. It actually equals only $10.5 million/day.
[EDIT] walterk beat me by a minute to that final math correction.