The growing proportion of renewable energy is posing great challenges for the electricity system. The electricity system must be able to adapt flexibly enough to the changing volumes of wind and solar energy. Pumped storage hydroelectricity plants can play a significant role. In April 2012, Germany, Austria and Switzerland (the "D-A-CH" countries) agreed to enhance their exchange and cooperation in relation to pumped storage hydroelectricity plants. Subsequently, a detailed three-part investigation of the legal and economic conditions of pumped storage hydroelectricity plants and their contributions to the power supply was initiated, which gave special attention to the trilateral prospects.

The legal situation for pumped storage systems in the three countries was assessed by the law firm Görg Partnerschaft von Rechtsanwälten mbB on behalf of the Federal Ministry for Economic Affairs and Energy (BMWi). The economic prospects were assessed in an expert report by the Workgroup for Infrastructure Policy (WIP) at the Technical University of Berlin on behalf of the Swiss Federal Office of Energy (SFOE), and the contributions of pumped storage hydroelectricity plants to the power supply are the subject of a study by the Institute of Power Systems and Power Economics (IAEW) of RWTH Aachen University on commission for the Austrian Federal Ministry of Science, Research and Economy (BMWFW). A report by the Energy Science Centre of the ETH Zürich on behalf of the SFOE presents an overview of the individual studies.