Wind farm repowering optimization: a techno-economic-aesthetic approach

When a wind farm (WF) approaches the end of its life cycle, repowering is another opportunity for wind energy to prove its value. This paper proposes an optimization framework to guide the WF repowering, considering the power generation, the economic cost, and the aesthetic of the WF when various types of new wind turbines (WTs) are added. When calculating the wake deficits inside the WF, a three-dimensional (3-D) Gaussian wake model is applied which considers the height differences among the new WTs. A harmony pattern metric is used to assess the visual impact of the rebuilt WF. This optimization problem is formulated as an integer programming (IP) problem and is tackled by the integer particle swarm optimization (IPSO) algorithm. The wind data used for this optimization procedure is predicted by the auto-regressive (AR) model. The case study on the OWEZ WF verifies the effectiveness of the proposed method. It is also validated that the application of predicted wind data is better than the historical data for WF repowering optimization.