The agreement is an extension of a deal signed in 2013, which would see Vestas install 836MW at projects developed by EGP in the US.
The developer said the deal is part of its "commitment to keep growing in the United States" and demonstrates its confidence it will qualify for the production tax credit (PTC).
EGP believes that because the agreement was signed before the expiration of the extension of the PTC, it will be eligible to claim the subsidy.
In December, the US Senate approved a bill to retroactively extend the PTC for another year, taking it to the end of 2014.
Vestas has already supplied a number of EGP projects in the US, including the 150MW Origin project in Oklahoma, which was completed last November.