SSE expects to finish its 34-turbine Keadby windfarm in summer 2014. It sits next to Keadby gas-fired power station, in North Lincolnshire.
When completed, the scheme will have a capacity of 68MW and produce enough electricity to power the equivalent of 57,000 homes.
Project manager David Sutton said: “This is an exciting point in the construction process and it’s great to see the first turbines generating electricity.”