In the mid – to long-term, energy storage systems may be necessary to balance the stochastic electricity production of renewable energies such as wind and solar. Many different storage solutions are either already technologically mature or on the brink of market introduction. However, regulatory barriers may hinder investments in storage capacity. Energy law in European countries typically defines very specific roles for different market participants, such as producers, grid operators or final customers. Storage systems often do not fit into these categories, or may simultaneously fall under several different rule sets. This raises many legal questions which have yet to be addressed by the courts. Especially problematic is the question of whether storage systems have to pay grid usage fees, which is closely related to their possible classification as final customers and may restrict many potential business models. This article compares the corresponding regulation in the main German-speaking (DACH) countries; Germany, Austria and Switzerland while also taking into account relevant EU legislation.