Germany-based Siemens said on Tuesday the order is its largest to date for an onshore wind project.
When installed, the turbines will have the capacity to produce 593 megawatts of power.
One megawatt of power can serve about 800 average U.S. homes.
Siemens will produce the turbines in Iowa and Kansas, and install and service them at three locations throughout Iowa.
The agreement comes after Siemens supplied 76 turbines to MidAmerican in 2008.
MidAmerican Energy, a utility owned by Buffett's Berkshire Hathaway, currently supplies electricity and natural gas to more than 700,000 customers throughout the U.S. Midwest.
Earlier this month, Siemens agreed to supply Dong Energy with a new generation of offshore wind turbines for experimental purposes.
(Reporting by Ernest Scheyder; editing by Gunna Dickson) Keywords: SIEMENS/MIDAMERICAN (email@example.com; +1 646-223-6119; Reuters Messaging:firstname.lastname@example.org) COPYRIGHT Copyright Thomson Reuters 2010. All rights reserved. The copying, republication or redistribution of Reuters News Content, including by framing or similar means, is expressly prohibited without the prior written consent of Thomson Reuters.