This is just a small typographic error but I must report it as it confused a bit the engineer in me.
The locked safe/container in the ship debris (which contains a hard drive) says it requires 40 MWH to open it. That is a unit of energy, not power. It would need 40 MW for 1 hour, or 20MW for 2 hours. I connected only one biomass reactor (20MW) and there was not indicator whatsoever of what I did wrong.
Of course as soon as I connected a second one, it opened instantly. So just delete the H at the end :)