Failed to load mods: Error while running setup for entity prototype "or_power_electric" (generator): fluid_box must exist and have a filter if 'max_power_output' is not defined.

I do have cargo ships working without Pelagos.

I can try to figure out what the conflicting mod is if needed, but I do have a lot of them

That would be nice.
Without knowing which mods could have conflict I can't debug it.

Hmm I've just reproduced the error on a clean version with just your mod and required dependencies. Factorio 2.0.65, with Space Age, Quality, And Elevated Rails

I usually have game locked few versions behind. It should work fine on older version (2.0.60)
I will check what's going on on newer versions

can't reproduce error
checked experimental 2.0.65 , 2.0.65 and 2.0.64
with no result
tried with only pelagos mod and with some combination with other mods
Loads fine every time

You can try to check file integrity on steam (if you have steam version), or remove "mods" folder, run game and then try to install it
also check if you have newest mod version

you can DM me on discord if these things won't help, if you want to help me find what's happening to make it work

Ah, it's a setting in Cargo Ships. You can turn off the onboard generator for the oil rigs.

That makes sense
I was overriding small generator filter setting to allow methane as a fuel for oil rig.

but it throws an error when you don't use it.

Small generator is usefull and that is default setting in cargo ships mod, so most people play with it enabled
Without this setting pelagos progession would be difficult.
I will do something with this error when releasing new mod version.

Thx for help

added setting to force small electric generator setting in 0.2.0 with explanation that game will crash if generator will be set to None