Technical and legal analysis of the grid-serving multi-use of battery storage systems for prosumers

Stationary residential battery storage systems (BSS) are mainly operated in a single-use configuration to achieve self-consumption increase (SCI) in which their technical potential is not fully utilized. Multi-use operations enable increasing the effective usage of BSSs' technical potential. This research investigates the application-based multi-use of BSS from both technical and legal perspectives. Two different grid-serving use cases are examined by stacking the applications SCI, ancillary services (ASm) and peak shaving (PS). The legal analysis of the multi-use shows that it is crucial when storing power from the grid, to feed it back entirely into the grid to avoid increased costs or loss of funding. Moreover, if power from renewable sources is stored, the BSS may not be used for storing power from the grid simultaneously. The technical analysis shows that the multi-use with SCI/ASm does not result in significant improvements in grid stability. SCI/PS can mitigate most violations of operational boundaries. The impact on the BSS, resp. the number of efficient full cycles and the self-consumption quota (SCQ), show only minor differences when stacking the applications. Nevertheless, the disutility resulting from the SCQ needs to be revised when setting financial incentives for grid-serving applications in multi-use operation of residential BSS.