The manufacturer will supply 101 of its G97-2.0MW turbine to be deployed at the Baffin wind farm being developed in the south of the state.
The turbines are set for delivery in mid-2014 with the facility predicted to go online towards the end of the same year. However, the project has not yet been granted local government approval.
Gamesa said in a statement that it believes Iberdrola is well positioned to deploy the turbines at other possible US sites if necessary.
The wind farm is the last phase of Iberdrola's Penascal complex which, once commissioned, will have capacity of 606MW.
This agreement marks the largest single order for G97 2MW model.