Search engine giants Google and Yahoo! are both doing their part to help the environment by going carbon neutral and reducing power use. Last week, Google ran a black homepage for a day and today Yahoo! announced plans to go carbon neutral by the end of 2007.

Google’s power saving initiative launched late last week in support of “Lights out San Francisco“. To raise awareness of the event, Google ran an all Black version of their homepage for users in the San Francisco area, reminding them to turn out their lights. A screenshot can be seen below:

From the Google Blog:

“Google users in the San Francisco Bay Area will notice today that we “turned the lights out” on the Google.com homepage as a gesture to raise awareness of a citywide energy conservation event called Lights Out San Francisco.

Given our company’s commitment to environmental awareness and energy efficiency, we strongly support the Lights Out campaign, and have darkened our homepage today to help spread awareness of what we hope will be a highly successful citywide event.”

In related news, Yahoo! has also confirmed their commitment to environmental change by setting targets to be carbon neutral by the end of this year. The company is following through on plans made earlier this year to back hydropower in rural Brazil and wind power in India.

According to Christine Page, Yahoo! director of climate and energy strategy, this is the equivalent of removing 35,000 cars from the road for a year, or shutting down the Las Vegas strip for two months. Yahoo! is buying carbon credits from projects in India and Brazil to offset the 250,000 metric tones of greenhouse gases the company uses each year.