To model investment in new wind power plants, you must know where is possible to build them.
Onshore wind: must respect current land usage, nature reserves and minimum distances from properties.
Offshore wind: must respect nature reserves, sea depth, shipping lanes.
Example for wind turbines: look at each country's rules / minimum distance regulations and look in detail at where buildings are and compute where each and every possible wind turbine could go.
Use CORINE landcover and other databases of nature reserves to get a coarse-grained potential.
See Wind Potentials Breakout Group Report from the Open Energy Modelling Workshop - London 2015.