This issue should be solved before merging #726 .
The way to solve this issue:

• copy DoA functions and adapt for NZE (leave the old functions of DoA to prevent merge conflicts with Feature/minimal degree of autonomy #726)
• adapt documentation
  the first point includes E3, tests, etc...

Degree of NZE will be defined as:

Note: NZE not DA (sorry in gif)

discussed with @smartie2076 2021-02-02:

• generation should only include renewable sources
• add link to definition in issue @SabineHaas (from short research)