Spoiler:
Singularity is awful and far too easy to fuck with.
Give engineers the option to add power cells to the shield generator which will automatically be used if the wires stop supplying power.
I'll leave the actual numbers up to people that can balance but I thought about 5000 per minute or so. That's 5 minutes if Science gets their shit together and is throwing huge cells at you (which is unlikely) -- and even that isn't enough to save the station, but it gives you enough time to power it back up and try not to get eaten.
