In 2015, the majority of the electrical energy generated was produced by fossil fuels and nuclear power. Climate change and storage of radioactive waste are negative effects of these energy sources on the environment. So these energy sources need to be replaced by a sustainable energy sector. Since 2000, especially wind and solar power capacity is expanded rapidly in order to replace above mentioned energy sources. This change, however, comes along with two problems. On the one hand, there is the timely alignment of electrical power generation and consumption and on the other hand, there is the local alignment. For the local alignment, a robust transmission system is required, while the timely alignment requires storage technologies. The presented work investigates and compares storage technologies (especially pumped-storage). Pumped-storage plant schemes with fixed speed and variable speed as well as binary and ternary sets are considered.^ ^Detailed loss models are developed, operating ranges are determined and based on these ranges, an operation optimization is carried out. For the operation optimization, the day-ahead market as well as the primary and secondary control market are taken into account. The determined income is further collated with the costs of different plants in order to evaluate the most profitable storage types. Due to its actuality, the economic analysis also takes battery storage applications into account. Based on the operation optimization transient models are developed to simulate transient behaviour of the hydraulic as well as the electrical part. The validation of the developed model, by comparing a measured power trend with a simulated one, is followed by the analysis of the vibration characteristic of the plant. Furthermore, the agility of the different plants is demonstrated by a one-day simulation.^ The best possible alignment of a predefined power reference signal and the simulated power trend is the focus of this simulation. Finally, the ability to compensate a power imbalance within the power system by changing the power output of the pumped-storage plant is investigated. It turns out that the ternary set is the most profitable one and that the variable speed schemes have, within a broad operating range, a better transient behaviour than the fixed speed schemes.