Upgrading turbines components could extend the lifetime of 42GW of this capacity, analysts at Wood Mackenzie suggested.
Such upgrades are often cheaper than alternative options like full project repowering.
However, regulatory barriers and project economics undermine many asset owners’ attempts to extend the life of their turbines, Wood Mackenzie argued.
At smaller sites, significant refurbishment or upgrades might not be economically viable due to supply chain constraints, for example, Wood Mackenzie suggested.
Meanwhile, owners of larger wind farms need to consider regulatory issues, financial risks, technical challenges and site or turbine operating conditions, before deciding between decommissioning, lifetime extension and repowering.
For example, the wholesale replacement of old turbines with new technology might be prohibitively expensive due to the cost of the latest generation of turbines.
Asset owners might also struggle to gain planning permission for larger turbines that dominate the landscape, Wood Mackenzie suggested.
Some asset owners may also be unable to source spare parts for less popular technologies or from defunct manufacturers.
The analysts argued new regulation is needed to prevent the removal of wind capacity reaching the end of its operational lifetime.
"Currently, minimal regulatory support is offered for repowered and lifetime extension projects, forcing asset owners to operate in a merchant power market," said Daniel Liu, principal analyst at Wood Mackenzie.
"However, the introduction of the post-2020 Renewable Energy Directive should provide clarity for asset owners to decide on whether to decommission, repower, or extend the lifetime of their onshore wind assets."
The analysts warned that the trend of carrying out lifetime extensions for onshore wind is still in its infancy, and so it is difficult to assess the effectiveness of the solution.
Depending on the level of retrofits and upgrades, lifetime extensions can be expensive, and cost comparisons between different solutions should be carried out.
For example, older turbines will require higher maintenance spending due to the increasing risk of components — like gearboxes, generators and blades — failing.
However, corporate power purchase agreements (PPAs) could also help provide cash flow security for asset owners whose projects’ support contracts have expired and are struggling to carry out a lifetime extension, the analysts added.