Google's data centre in Council Bluffs, Iowa, will source its energy from a number of wind farms that are part of MidAmerican's Wind VIII programme.
The initiative will see the Warren Buffet-owned company bring more than 1GW of wind projects online in Iowa by the end of 2015.
The deal means that the new Google data centre will be fully powered by renewable energy. It also allows for further additions to the data centre to be covered by the agreement.
In 2013, Facebook also signed up to source the energy for its new data centre in Iowa from the nearby 138.6MW Wellsburg wind farm, being developed by MidAmerican.
To date, Google has bought stakes in 16 renewable energy developments, including seven wind projects, as it looks to reduce its carbon emissions, particularly from its energy-intensive data centres.
These projects accounted for 22% of the company's total energy consumption in 2012. Along with green power bought from the grid, 34% of its power came from renewable sources.
The nameplate capacity of Google's renewable energy projects is now more than 2GW as it pushes towards its goal of using 100% green energy by an unspecified date.