Supercomputing of the highest performance class is represented in Germany by the Gauss Centre for Supercomputing (GCS), an association of the three national supercomputing centers, the High Performance Computing Center (HLRS) in Stuttgart, the Leibniz Supercomputing Centre (LRZ) in Garching near Munich, and the Jülich Supercomputing Centre (JSC) at Forschungszentrum Jülich, which was the first to be established and will celebrate its 30th anniversary this year. Together they currently offer a performance of more than 20 petaflops (20 times 1015 floating point operations per second) to computational scientists in Germany (and elsewhere in Europe, to some extent). This performance is urgently needed for research projects across many disciplines, such as fluid dynamics and engineering, earth and atmospheric studies, materials science and chemistry, astro- and elementary particle physics, biology and medicine. Most of the resources are granted to research groups at German universities. Scientists gain access to the high-end systems of GCS after successfully passing a well-established, transparent evaluation process that ensures the highest quality. High-performance computing (HPC) at an internationally competitive level is an important driving force for innovation, and requires thinking ahead, both at the operational level, where rational decisions concerning the development of the supercomputer technology have to be made, and at the scientific level, where the potential to create new insights using HPC has to be explored. As an example, this article discusses the energy consumption of novel magnetic structures for spintronic applications.