Electricity storage systems in the future German energy sector: An optimization of the German electricity generation system until 2040 considering grid restrictions

Due to the growing feed-in of electricity based on renewables, electricity storage systems will be essential in the future energy sector. Because of the volatile feed-in, electricity will have to be shifted temporally. Additionally, load centers and regions of potentially high wind-based electricity production are located far away from each other in Germany, resulting in the need to transport electricity from the north to the south. According to the targets defined by the German government, more than 60% of electricity generation in 2040 is to be based on renewables. A strategic allocation of storage systems might help to improve the utilization of grid capacities and integrate renewables at the same time. To analyze this, we implemented the possibility to commission storage systems throughout Germany in the energy system model PERSEUS-NET-ESS. This investment and dispatch model includes a DC approach of the German transmission grid and, thus, calculates not only the installed capacities, but also their optimal allocation. Besides storage systems, gas turbines or load shift potentials can be used for the integration of renewables. In this paper, we use PERSEUS-NET-ESS to evaluate the alternatives taking the grid restrictions into account. Results indicate that it is beneficial to commission about 3.2 GW of battery storage systems until 2040, provided that storage investment will drop to about 150 €/kWh until then. The main part of the capacity is to be deployed in northern Germany close to the sea, where electricity from off-shore wind parks will be fed into the grid. At the same time, the storage systems will be located mainly close to congested grid lines. For the case of battery storage systems being impossible in the model, gas turbines are commissioned instead. Modeling will also consider the load shift potential due to electric mobility. It can substitute almost all of the commissioned storage systems and at the same time reduce the total generation capacity needed.