neoshagrath wrote:It is actually for every % of energy you lack for the required energy, your mines' output decreases by that %.

Sample:
all of your mines require a total of 1,000 energy for 100% output. If you only have 600 energy ( - 400), all your mines will only give 60% output.
Let's say your metal mine alone needs 400 energy. You can completely shut it down which will bring down the energy you need to 600. ( 0 )
This should allow the crystal mine and the deuterium synthesizer to both give 100% output.

Excess energy will not give you extra production.
You also have a basic income which is unaffected by the energy.