This article by James Lawson originally appeared June 17 on the Renewable Energy World website
UK — By 2020, swapping aging wind turbines with more powerful modern units will have raised annual electricity generation at refurbished sites from 1,524 GWh to 8,221 GWh. A 2-MW wind turbine coming off the production line with a rotor diameter of 80 metres can generate four to six times as much electricity as the 1-GWh annual yield of a 500-kW wind turbine with a 40-metre rotor built in 1995. This is the fundamental thinking behind wind repowering.
Replacing old machines with fewer, larger and taller modern units that are quieter, far more reliable, and capable of producing vastly more electricity is an activity that has increased significantly during the last five years, according to GlobalData’s 2012 report Wind Repowering. The report says the value of the world’s repowering market will grow massively in the next five years. In 2011 wind farms producing around 183 GWh annually were replaced with turbines capable of generating 774 GWh. But by 2020, repowering will drive an increase in annual power generation at repowered sites from 1,524 GWh to 8,221 GWh.