In the context of the increased acceptance and usage of electric vehicles (EVs), vehicle-to-building (V2B) has proven to be a new and promising use case. Although this topic is already being discussed in literature, there is still a lack of experience on how such a system, of allowing bidirectional power flows between an EV and building, will work in a residential environment. The challenge is to optimize the interplay of electrical load, photovoltaic (PV) generation, EV, and optionally a home energy storage system (HES). In total, fourteen different scenarios are explored for a German household. A two-step approach is used, which combines a computationally efficient linear optimizer with a detailed modelling of the non-linear effects on the battery. The change in battery degradation, storage system efficiency, and operating expenses (OPEX) as a result of different, unidirectional and bidirectional, EV charging schemes is examined for both an EV battery and a HES. The simulations show that optimizing unidirectional charging can improve the OPEX by 15%. The addition of V2B leads to a further 11% cost reduction, however, this corresponds with a 12% decrease in EV battery lifetime. Techno-economic analysis reveals that the V2B charging solution with no HES leads to strong self-consumption improvements (EUR 1381 savings over ten years), whereas, this charging scheme would not be justified for a residential prosumer with a HES (only EUR 160 savings).

The rapidly falling capital expenditures and rising energy and power densities of battery energy storage systems are leading to more widespread use of these systems in both mobile and stationary applications. In stationary applications, it is expected that the economic potential of a battery energy storage system will improve when serving multiple applications simultaneously. In this work, the newly developed tool, Sim-SES Mutti-Use, is introduced, which is capable of simulating an energy storage system that serves multiple applications simultaneously. Furthermore, the techno-economic impact of multi-use operation strategies on the energy storage system is explored. In its present state, the tool allows the modelling of several applications, depending on the scenario explored. Available applications include: frequency containment reserve, peak shaving, self-consumption, and compensation of reactive power. In line with other publications, simulations conducted in this work confirm, that the stacking of applications is more lucrative than single-use operation. Both economic and technical characteristics of the battery are considered in this work.