The turbines will be used at the company’s Block Island project off of Rhode Island. The development is being used to provide a test case for a larger 1GW project in the same area.
Previously the project was scheduled to be installed next year. However, Deepwater Wind said it would be between 2013 and 2014.
Speaking about the deal, Deepwater Wind’s CEO William Moore said: "The Siemens turbine is the future of offshore wind and our partnership with Siemens is a huge advancement and advantage for the Block Island Wind Farm.
"Not only is Siemens one of the leading technology firms in the world, but they have now agreed to supply Deepwater Wind with their very latest wind-turbine technology, one that will move our entire industry forward."
Unlike many of the other next generation turbines currently in development, Siemens built a prototype before the machine was officially launched. It is direct drive and has a 120-metre rotor.
Earlier this year, Siemens signed a development deal with Dong Energy to test two 6MW turbines and one modified SWT-107 3.6MW turbine for development at the latter’s Avedore Holme test site.
It is likely the largest number of 6MW turbines is destined for the UK’s 5GW Hornsea offshore project in the North Sea, which Siemens part owns. It is likely to come into operation around 2015.