  The best wind locations are nowadays often occupied by old, less efficient
and relatively small wind turbines. Many of them will soon reach the end of
their operating lifetime, or lose financial support. Therefore, repowering
comes to the fore. However, social acceptance and land use restrictions have
been under constant change since the initial expansions, which makes less area
available for new turbines, even on existing sites. For the example of Germany,
this study assesses the repowering potential for onshore wind energy in high
detail, on the basis of regionally differentiated land eligibility criteria.
The results show that under the given regional criteria, repowering will
decrease both operating capacity and annual energy yield by roughly 40\,\%
compared to the status quo. This is because around half of the wind turbines
are currently located in restricted areas, given newly enacted exclusion
criteria. Sensitivity analyses on the exclusion criteria show that the minimum
distance to discontinuous urban fabric is the most sensitive criterion in
determining the number of turbines that can be repowered. As regulations on
this can vary substantially across different regions, the location-specific
methodology chosen here can assess the repowering potential more realistically
than existing approaches.
