The concrete sphere operates much like pumped storage hydropower. According to the institute, the test successfully proved the function of the storage concept, and researchers are evaluating the data to improve on the developed models.
In a follow-up project, Fraunhofer wants to test a larger sphere in the sea and conduct longer-term tests. For this purpose, Fraunhofer said, the results from the Lake Constance trial have to be assessed in more detail, for example in Southern Europe or in Norway. New tests could take three to five years to complete.