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