In 2024, Germany’s residential battery storage system (BSS) capacity grew by 46%, reaching 14.9 GWh. The application-based multi-use, i.e., revenue stacking, has proven to be suitable for maximizing the utilization of the residential BSS’s techno-economic potential and increasing prosumer profit. Nevertheless, previous research has shown that the current German legal framework places financial burdens on the multi-use.

Recent amendments to §19 par. 3 EEG, regulating the payment claim for BSS, i.e., here feed-in remuneration and market premium, aim to remove these burdens. Under the unchanged exclusivity option (§19 par. 3a EEG), BSS are only eligible for feed-in remuneration or market premium if charged exclusively by photovoltaic (PV), excluding drawing grid power. Under the metering option (§19 par. 3b EEG), renewable energy is only eligible for a market premium, which intends direct marketing of both PV and BSS. Here, a second meter distinguishes PV- from grid-sourced energy, granting feed-in remuneration for PV energy, both directly from PV and BSS, and levy netting (§ 21 EnFG) for grid-fed power. Within the flat rate option (§19 par. 3c EEG) only direct marketing is possible. The flat rate option applies a uniform rate to both PV and battery feed-in, capped at 500 kWh per kilowatt of installed PV capacity.

This study applies a mathematical optimization model to annual simulations of exemplary residential prosumers, evaluating the techno-economic impact of the revenue stacking (self-consumption increase, frequency containment reserve, spot market trading) with recent amendments to §19 EEG. First results show that the metering option yields the highest prosumer profits, regardless of the considered additional metering cost. The flat rate option closely approaches the profitability of metering. The exclusivity option has the lowest potential due to the BSS being restricted from grid charging.