Analysis of scenarios for repowering wind farms in Brazil

In order to extend the useful lifetime of a wind farm, wind turbine repowering is an option. Repowering may be applied due to the turbine's aging, reduction in turbine yield or in the wind farm revenue, new technologies available or increasing operation and maintenance costs. This work seeks to identify the repowering potential in Brazil and to simulate different technical-economic scenarios to determine which parameters are more relevant for a repowering project. In the technical perspective, it was sought to analyze how the technological progress of wind turbines influences energy production, while in the economic context it was attempted to understand which financial indicators are more relevant and how they vary according to the energy selling tariff. The technical evaluation showed that repowering should focus on wind turbines with less than 2.0 MW. For wind farms with high financial incentives, a higher energy price is needed in order for the financial parameters to reach the ones from the original project. Meanwhile, wind farms that do not have such benefits, like the ones that have been built over the last years, demand lower tariffs to the repowered wind farms to become attractive. In the cases analyzed, tariffs between 23.23 US dollars (USD) and 33.56 USD showed interesting results for both situations. Energy auctions in Brazil have shown a tendency of lowering tariffs and, thus, repowering tends to become attractive soon, showing that the economic life of a wind turbine may end before its useful life.