Circular Transitions in Wind Energy

This thesis investigates the climate benefits of applying circular strategies in the repowering of wind turbines, particularly through the reuse of components such as the foundations and towers. The study combines life cycle assessments and site-specific energy calculations for three wind turbines located at two different sites in Sweden. This information is used to examine how carbon dioxide intensity changes due to repowering and what potential climate advantages it may bring. The results show that the components with the greatest climate impact during manufacturing are the tower and foundation. The emissions are associated with the production of steel and concrete, respectively. When these components are reused, greenhouse gas emissions are significantly reduced. Repowering with used components reduced the carbon intensity of all turbines even in a worst-case scenario, with lower wind speeds and shorter life span. The findings are consistent with previous research. Kaser (2022) and Martínez et al. (2018) have shown that reuse alternatives in repowering are often more resource effective than new construction, due to initial emissions being lower. This study builds on their findings by applying them to Swedish conditions and by including new possibilities for component compatibility between turbines and towers from different manufacturers. The work also demonstrates that established frameworks for circular economy and circular business models are directly applicable within the wind energy sector, though policy support and cooperation between stakeholders are needed to realize them in practice. The study thus contributes to the development of sustainable and circular energy systems. An important aspect emphasized in the role of carbon intensity in a broader energy system perspective. Small reductions in carbon intensity often translate into a system effect of nearly 600g CO2e/kWh when compared to Sweden’s average marginal emissions factor. This means every kWh of energy produced displaces fossil-based marginal production and provides significant climate benefits. In summary, the study shows that reuse in repowering in not only technically feasible but also justified from both a climate and system strategy perspective. By linking circular economy approaches to tangible climate benefits, the work contributes to both academic discussion and practical decision-making within the field of renewable energy.