The water company had its initial plan to place a turbine at the Fabian Way site in Swansea turned down by city planners in July 2012, and the revised plans turned down in October last year.
Following a successful appeal, Welsh Water will now develop a 79m, 500kW turbine which is expected to contribute more than a quarter of the total electricity consumed at the wastewater treatment works.
Welsh Water’s head of energy, Mike Pedley said: “We are delighted that we have now been granted permission to erect a wind turbine at our wastewater treatment works on Fabian Way.
“We believe that our green energy scheme is right for the area and in designing the project we worked hard to ensure that the location and size of the turbine complied with the local authority’s own planning guidelines on turbine developments.”
Work is due to start in late 2015, with the turbine expected to be operational during 2016.