Oh, in SH you are allowed to build 30m² sheds without a permit? That's crazy. In Berlin, a maximum of 10m² is allowed, which I already find restrictive. Carports are allowed up to 30m² as well).
Just checked myself again. Watch out! Small houses (and that also includes your shed) are only allowed to have 30m³ (cubic).
So either a carport with a storage room together having 30m² (square) and then you build an additional carport (again max 30 m²) or a carport with 30 square meters and a shed with 30 cubic meters.