The growing number of ageing wind and solar projects will make repowering an increasingly important source of new renewable capacity, according to analysis by Wood Mackenzie. In its September 2026 Horizons report, Renewing renewables: the next chapter in the energy transition, Wood Mackenzie forecasts that more than 2.5 TW of wind and solar projects will face decisions over decommissioning, lifetime extension or repowering during the 2040s. Repowering ageing projects will become an important contributor to installation and output growth alongside new developments.
Wind decommissioning is already increasing. Wood Mackenzie estimates that more than 30 GW of wind capacity will have been decommissioned globally by the end of 2026. Almost 50 GW of wind capacity is currently more than 20 years old, a figure the consultancy expects to rise to more than 230 GW by 2040 and around 440 GW by 2050.
Larger turbines and existing infrastructure
Repowering can allow developers to retain some existing infrastructure while replacing older turbines with newer technology. According to Wood Mackenzie, the average wind turbine rating increased from 1.5 MW in 2006 to 6 MW in 2026 and is forecast to reach 7.5 MW by 2036.
The consultancy also points to improvements in hub heights, rotor diameters, automatic controls and condition-monitoring systems as factors that can increase output from existing wind sites. Turbine design lives have also increased from around 20 years to more than 30 years, while time-based availability after degradation is reported at around 97%.
Repowering can also benefit from existing grid connections, land, access infrastructure and previous planning approvals. However, Wood Mackenzie notes that grid capacity and permitting restrictions can limit the amount of additional capacity that can be installed at an existing site.
The consultancy estimates that 44% of wind additions during the 2040s will be driven by decommissioning. In established European markets, it expects decommissioning to account for more than 70% of installations during the same period, compared with as little as 1% in some emerging Asian markets.
Wood Mackenzie concludes that the ageing renewable fleet will increasingly affect equipment demand, asset valuations and decisions on whether to extend, sell or repower existing projects.
