By 2030, a total of wind power installed capacity between 40 GW and 80 GW will have reached its useful lifetime in Europe [1]. The decommissioning of these assets may compromise the EU effort to reach 451 GW of wind power capacity by 2030.

• Repowering offers a convenient way to maintain, or even increase, this installed capacity. It basically consists of replacing older power stations with newer ones that either have a greater nameplate capacity or more efficiency which results into a net increase of power generated. WindEurope envisions that about 50% of turbines reaching end of life are to be repowered, i.e. 8 GW per year of capacity by 2030 [2]).

• Repowering has several benefits. It significantly improves the capacity factor. When the rated power remains constant, a repowered wind farm is expected to generate less noise, to have lower visual impact and to have lower impact for birds and bats [3]. The CO2 cost of repowering is offset by the benefits [1]. Repowering projects come with lower capital investments compared to greenfield projects since a part of the infrastructure can be reused. However, the net present value can still be negative. The evaluation of the project profitability requires an energy yield assessment.

• MINES Paris (PSL), DTU and Engie Green recently started a Ph.D. to define the best methods for energy yield assessment for repowering. This poster presents preliminary results from the Ph.D.