Posters

Abstract

The topic of hybrid plants has been gaining importance in the last few years, over the prospect of a renewable source of energy that can supply power steadily during the day, and throughout the whole year. When installing a wind farm, and in order for it to be financially profitable and energetically interesting, a minimum of production needs to be ensured. Nonetheless, due to the high variability of the wind resource, production can vary greatly throughout the year, and it is heavily dependent on the characteristics of the selected location. Variability leads to high uncertainty that can difficult the establishment of PPAs and even risk the viability of the wind farm project. On the other hand, solar power plants may seem an equally variable energy source, but when studied seasonally, shows lower variability and a stable behavioral pattern, which can benefit a hybrid plant with a wind farm. However, solar plants almost always have lower equivalent hours, which will bring down the productivity of the hybrid plant. This struggle causes developers to reassess the possibility of hybridizing. Complementarity of the energy sources in the location is one of the most relevant factors when studying the profitability of a hybrid project. High complementarity reduces curtailment losses severely, and a constant energy flow is also necessary for some specific purposes, such as hydrogen production via electrolysis, making it an important variable to analyze. In addition to that, we wanted to delve into the importance of the complementarity in the uncertainty of the hybrid plant. Analyzing the uncertainty of any wind farm or solar plant is a complex task that can be approached by considering the inherent variability and behavior to have a normal distribution. If that model does not render accurate results, due to icing, seasonal effects or any other factor, a stochastic method need to be applied. Nevertheless, assessing the uncertainty of a hybrid plant is not as straightforward at it may seem at first sight. Individual uncertainties need to be examined in first instance to find interactions between them, so the propagation law can be applied adequately and the variabilities considered jointly. The results found with this analysis, however, were surprising: we found that hybridizing solar and wind power can give resulting power plants with an uncertainty that is lower than either of the separate plants. Even though it is counter-intuitive when compared to production result, if the wind and solar energy have high complementarity, which depends heavily on the project location, it can ensure a stable power source, which partly mitigates the inherent variability of the wind, and severely reduces the variability of the hybrid plant. Whereas the total productivity and equivalent hours of a hybrid plant is always in between the individual results, uncertainty does not necessarily follow the same rule, which makes the development of a hybrid plant with uncharacteristically low uncertainties possible, that could even equate renewable power plants to conventional energy sources in terms of financial risk.