The seven Vestas 2MW turbines flanking the train tracks and E40 motorway are expected to produce 35,000MWh/year.
Around two-thirds of this will help power high-speed and regular trains on three lines carrying approximately 170 trains a day, while the remainder will feed into the national grid.
The €21-million project is the first phase of a facility that will eventually comprise 25 turbines totalling 50MW owned and developed by Greensky.
Greensky is a joint-venture between Electrabel (50%), Infrabel (10%), the Brussels Electrical Intercommunity (IBE; 17%) and the town of Sint-Truiden (23%).
A second phase comprising 18MW is slated for commissioning in late 2016, while the final 18MW is in the last stage of the permitting process, Greensky said.