Decreasing feed in tariffs and system prices combined with an increase of electricity tariffs supports the trend to install PV storage systems in private households. In the past years several investigations and field trials have shown, that these systems can increase the self consumption of PV-power and support the self sufficiency of private households. These systems also have a positive influence on the low-voltage grid.
In recent years several investigations have been done to determine the optimal system configuration. They focus on the storage and PV generator size or the applied storage technology. In general, the mode of operation follows a simple regime: If PV production is larger than the actual consumption, PV power is stored. If the local consumption is higher than the actual PV production, stored power is used as long as available. Only slight modifications have been done, to map the price and efficiency effects of power electronics. Therefore, the results are limited to a single mode of operation. In this presentation, we derive a mathematical framework, which allows the calculation of the upper performance limit for a specific household and storage system, without any assumption on the operation strategy. We apply these analysis to a large set of German households and compare the upper performance limit for two different storage system designs: A system with relative short lifetime and small capacity on the one hand and another with a long lifetime and larger capacity.