The Rhyd-y-Groes plant on Anglesey has 24 turbines with a capacity of just 300KW each, which have been spinning since 1992.
The project, which is owned by TPG Wind, a join venture between E.on and Eurus Energy, is set to have 20 new wind turbines installed that will generate up to 18MW.
"While it's still early days, we're hoping to replace the current turbines with modern turbines capable of producing more energy. We will be conducting formal studies and hope to be a position to submit our planning proposals by spring 2014," said consents manager Paul Hunt.
Public information days will be held early next year in order for local residents to share their views.