Objective The renovation and upgrading of old wind farms through "replacing small with large", fully tapping into the value of existing wind and land resources, and improving the efficiency of existing wind farms, is an important guarantee for promoting the development of new energy and achieving the "3060" carbon peaking and carbon neutrality goals.

Method This article provided an overview of the current status of wind farm renovation and upgrading, investigated the policy situation, conducted research and analysis on typical renovation and upgrading projects, and summarized the experience and existing problems of current progress.

Result The national policies for the renovation and upgrading of old wind farms are clear, local policies are gradually being implemented, and the external environment is improving. The advanced experience of successfully renovated old wind farms includes actively communicating with regulatory authorities, fully benefiting from policy dividends, fully utilizing old wind farm equipment, effectively reducing construction costs, developing technical solutions tailored to local conditions, and achieving cost reduction. However, large-scale renovation and upgrading still face significant problems such as prominent new energy consumption issues, difficulty in capacity expansion and renovation, increased uncertainty in electricity prices, and incomplete asset recovery paths.

Conclusion To further enhance the efficiency of the renovation and upgrading of old wind farms, the industry still need to focus on the applicability of policy to the boundary conditions of renovation projects, selection of wind turbines, optimal layout of wind farms, consideration of environmental benefits of renovation of old wind farms and selection of reasonable financial evaluation methods, among other key directions, to promote the healthy, green and efficient the renovation and upgrading of old wind farms.