Optimization of a hybrid storage system and evaluation of operation strategies

Abstract The main goal of this research work is the optimal dimensioning of battery storage systems. In particular, a combination of lithium-ion and lead-acid battery systems, participating on the primary frequency control market, are considered. Because the fall in market prices the profitability is also falling. To enhance the economy of a battery system, a power distribution strategy are developed. In the first, two different approaches of power deviation between the lithium-ion and lead-acid battery system are evaluated. Based on the results of this first approach, the most profitable dimensioning was determined by using an optimization algorithm. The second approach comprised the coupling of the battery systems with a power-to-heat unit. Besides the new economic potential of this second approach, this combination allows a new operation strategy, which was also analyzed. For both cases, the optimal battery capacity with high profitability, depending on trading standards and regulations as well as on operation strategy, was determined.