Apple may have kicked off the Earth Day festivities, but Cupertino isn't the only tech giant going green. Google today announced plans to supply its Iowa data center with up to 407 megawatts of 100 percent renewable wind energy.

The newly inked agreement with MidAmerican Energy covers Google's current facilities, as well as future expansions supplied by renewable energy.

"This is our seventh and largest renewable energy commitment to date," Google's head of energy strategy and development, Neha Palmer, and energy program manager Sam Arons wrote in a blog post.

This deal brings the total amount of renewable energy contracted by Google to more than one gigawatt, or 1,000 megawatts.

"We've entered into a few different kinds of agreements over the years," Palmer and Arons said, "sometimes signing power purchase agreements (PPAs) with wind farm developers and sometimes working with our local utility partners."

Today's agreement—similar to one made in Oklahoma in 2012—provides wind power bundled with and tracked by renewable energy certificates generated by MidAmerican Energy's Wind VIII program.

Expected to be complete sometime next year, the expansion project will give the Warren Buffett-owned power company the capacity to generate more than 3.3 gigawatts of clean electricity via wind.

"But it's not just our own operations we want to green: Google has also invested over $1 billion in 15 renewable energy investments around the world in an effort to put more renewable energy on the grid and reduce global greenhouse gas emissions," Palmer and Arons said.

The search giant opened the doors to its private data centers in the fall of 2012 with a photo-heavy website featuring never-before-seen images of the technology, people, and places that keep the company running.

For more, check out How to Recycle Your Technology, as well as 10 Energy-Conserving Gadgets to Help You Save Some Green and "21 Ingenious Ways to Repurpose Your Old Tech" in the slideshow above.