Google has signed its seventh and largest commitment to purchase renewable energy with a deal to purchase 407 MW of wind power from MidAmerican Energy Holdings.

The contract brings Google’s total renewable energy commitment to more than 1000 MW and brings it a step closer to its target of being 100 per cent powered by renewables.

The wind energy purchased from MidAmerican will power Google’s data centre in Iowa. The agreement will not only cover the existing facility but will also allow for future expansion, said Google in its green blog.

MidAmerican Energy will sell energy to the Iowa data center bundled with and tracked by renewable energy certificates generated by projects that are part of its Wind VIII programme, under which the utility aims to build over 1000 MW of wind by the end of 2015.

Google currently uses renewable energy to power over 34 per cent of its operations. In addition to purchasing green energy, the internet firm also pilots and tests new technologies and has invested over $1 billion in renewable energy projects.