130% production on average, with excess being stored, minus losses in conversions, transport and storage = 100% demand covered all the time.

Or the longer version: For a stable grid I need to cover 100% of the demand in next to real-time. This can be achieved with enough long- and short-term storage, plus some overproduction to account for storage losses. The 115% to 130% production (compared to actual demand) are based on studies for Germany and vary by scenario, with the higher number for the worst case (people strongly resisting all changes to better balance consumption and south Germany keeping up there resistence to diversify by only building solar while blocking wind power).