Hmm, Geothermal would also be a good reason to have water pipes and steam pipes going everywhere, as well as possible standing water from broken pipes. Sounds like perfect hive conditions...
This is what I was complaining about earlier ("I want a biodome!" "I want a pit of doom!" "I want space toilets!")
We're getting into a convoluted theme. The first idea was power station. Then it was suggested to make it a hydroelectric power station. Which means you're mixing a power station with lots of water (FYI a hydroelectric power station is the most boring place on earth. It's got only two main rooms: A huge turbine room, and a control room. Weeee...). Now we're doing geothermal power station so we can mix lava, power, AND water themes? What next, put a shipyard on it too? And a battleship? Keep in mind we have limits, and water tends to UNBELIEVABLY RAPE R_SPEEDS.
I'm just up for a basic, functioning, power station. A very 'sterile' feel around the marine areas (blue/white lighting does wonders for this, combined with steel colors), and due to the nature of reactors, you have LOTS of good places to plop alien hives and such.
And one VERY IMPORTANT thing that I hate: If per chance we did make this a hydroelectric powerstation, then any 'theme' water you use would HAVE to be lethal. Why? Because it's just STUPID that the Kharra would be magically contained within a tiny building, when there's an entire world full of potential life right outside the doors. The thing with the current official NS maps is that they're in space, or on hostile terrain, meaning they have to remain inside. A hydroelectric power station with clean, fresh water just makes no sense.