Berkshire Hathaway’s MidAmerican Energy has awarded Siemens Gamesa what is said to be North America’s largest repowering deal to date.

The German-Spanish OEM will supply and install 163 of its SG 2.7-129 machines (operating at a 2.38MW mode) and 18 previously-sold SWT-2.3-108 turbines, to repower the Rolling Hills wind project in Iowa.

After repowering, the project in Adair, Adams and Cass counties will have a capacity of 429MW.

The wind farm currently features 193 SWT-2.3-101 turbines.

“This new project is a testament to MidAmerican Energy’s confidence in us as well as Iowa, where we have supplied them with more than 2.6 GW,” said José Antonio Miranda, chief executive of Onshore Americas at Siemens Gamesa Renewable Energy.

“The blades will be produced right there in Iowa and the nacelles and hubs will come from neighbouring Kansas, making this a truly local project.”

Berkshire Hathaway is owned by US billionaire Warren Buffett.

The repowering project includes replacement of the blades, hubs and nacelles for all units, and top tower sections for the SG 2.7-129 units. Commissioning is expected for late 2021.