The ROCK beamline (ROCK being the acronym for Rocking Optics for Chemical Kinetics) is devoted to the study of fast kinetic processes in nanomaterials used in catalysis and batteries. The objective is to contribute to the development of more efficient catalysts and batteries which should find successful industrial applications in the field of energy generation and storage in compliance with the protection of public health and environment. The better knowledge at the atomic scale of nanomaterials involved in catalysis or energy storage provided by time-resolved XAS is recognized by the concerned communities as mandatory for establishing synthesis strategies leading to important breakthroughs in the production of energy from renewable sources and in the development of advanced energy storage devices.