Dear Christian, dear community,
we already solved this problem via email, but for our community I wanted to explain the problem and the solution.
After a not complete calculation negative stocks for electricity was caused. This happend, because on the main net level not all processes could calculate completly. The main challange here was to model a model which calculate without erros. When every process with electricity in the input side is calculated, the electricity dataset can deliver the energy.
Regards,
Tobias