From the end of 2013 to the end of 2015, Brazil faced serious challenges to supply its demand for electricity due to a prolonged drought in the Southeast and Northeast regions with the consequent loss of hydroelectric generation. This paper presents an historical analysis of major world energy crises from 1988 to 2015 and in Brazil from 1924 to 2015. Analysing the natural river flow of key Brazilian dams from 1931 until 2017, this paper suggests that hydropower generation in Brazil has a 10–15 years cyclical pattern of hydropower generation. The periods of drought in this cyclical pattern usually coincides with energy crises due to the reduction in hydropower generation. It was found that the drought in 2015 had an impact of 110 TWh in hydropower generation, from which 25 TWh are due to head loss and 70 TWh are from lack of stored hydropower in July of 2014. In addition, 48 TWh were not generated due to delays in the construction of new power plants. Other causes of the Brazilian energy crisis of 2015 are presented and the overall electricity generation impact of these causes are compared. In addition, this paper presents the impacts on the energy, water and food supply sectors in Brazil, and the strategies employed to reduce the impact of the crises. With the intention of preventing future energy crises, the paper then shows the potential alternatives to improve electricity supply security in Brazil, particularly in terms of diversifying and widening the share of renewable sources and increasing the energy storage potential of the country.