Policies and design elements for the repowering of wind farms: A qualitative analysis of different options

Repowering of a wind farm is the process of replacing existing wind turbines with new turbines that either have a larger nameplate capacity or more efficiency, resulting in a net increase of the power generated. Although repowering brings, both, social and private benefits, there are also several obstacles to repowering which justify public support. The aim of this paper is to provide an overview and a qualitative analysis of instruments and design options to support repowering of on-shore wind farms. The multicriteria analysis carried out in this paper shows that all instruments have their advantages and drawbacks. However, feed-in tariffs and investment subsidies seem to be particularly appropriate instruments in this regard. Furthermore, we provide an assessment of different design options to promote repowering according to key assessment criteria. The relevance of design elements hinges on the fact that these are the ones directly affecting the variables that are relevant in the decision to repower (capacity factors and investment costs).