Energy in the solar system is constantly being converted from one form to another. Often these processes take the form of dramatic events such as solar eruptions or geomagnetic storms with important societal impacts. Understanding energy conversion and magnetic storms is one of the grand challenges facing science and poses a great cultural and scientific puzzle. We plan to use a new modelling approach based on combining state of the art supercomputers with state of the art numerical methods that allow us to capture the key aspect in energy conversion: the interplay of small and large scales. At the core of energy conversion is the ability of macroscopic systems to store and process vast amounts of energy while at the same time requiring microscopic processes at the moment the energy is released. To describe and predict how energy can be stored for long periods and why it is then suddenly released, a complete description down to the level of tracking the trajectory of single particles is needed.