How Does ENSO Impact the Solar Radiation Forecast in South America? The Self-affinity Analysis Approach.

The major challenge we face today in the energy sector is to meet the growing demand for electricity with less impact on the environment. South America is an important player in the renewable energy resource. Brazil accelerated the growth of photovoltaic installed capacity in 2018. From April of 2017 to April of 2018, the capacity increased $1351.5\%$. It is expected to reach the value of $2.4\ GW$ until the end of the year. The new Chilean regulation request that 20\% of the total electricity production in 2025 must come from renewable energy sources. The aim of this paper is to establish time series behavior changes between El Ni\~no Southern Oscillation and the solar radiation resource in South America. The results can be used to validate forecasts of energy production for new solar plants. The method used to verify the behavior of the time series was the Detrended Fluctuation Analysis. Solar radiation data were collected in twenty-five cities distributed inside the Brazilian solar belt, plus six cities in Chile, covering the continent from east to west, in a region with high potential of solar photovoltaic generation. The results shows the impact of El Ni\~no Southern Oscillation on the climatic behavior of the evaluated data. It is a factor that may lead to the wrong forecast of the long term potential solar power generation for the region.