Saw in the description that accumulators in the same network as this borks.
However, browsing the threads I found what, at least, seems to be the issue:
https://mods.factorio.com/mod/CW-hydrogen-power/discussion/5d889820d8363a000d5eb4f4
prototypes/entities.lua
generator.energy_source.usage_priority = "secondary-output"
electrolyser.energy_source.usage_priority = "secondary-output"
Maybe include this "fix"?
I have not gotten there yet, so lets see if things work out.
