[GS] Powerplants should be a separate District

[acluewithout]

Powerplants should be separate District, not a building in the Industrial Zone.

This would make power generation more interesting, let the IZ become a more interesting district, and overall in prove strategic challenge.

How would it work?

• Powerplants would be a new late game District. They would be separate to Industrial Zones and would unlock at Industrialisation.
  
  
• Cities could have multiple Powerplants. Powerplants wouldn’t count against the City’s District limit. Powerplants can be built in the usual way, or you can purchase them with Gold in any City with a Governor. (This would allow you to build them more quickly given they’re only available in the late game.)

• You can build either a Coal, Oil or Nuclear Powerplant, and all subsequent Powerplants built in that City would be of the same type. You can also run a project to convert all your existing Powerplants in a City to a different type if you wish.
  
  
• Powerplants can be built on Coastal Tiles once you research Synthetic Materials.
  
  
• Powerplants would largely generate power the same way they do now. The only differences would be that each Powerplant can you produce a maximum of X power, so if you require more power you’ll need additional Powerplants (in addition to needing fuel to support all those Powerplants). Note that Powerplants would generate power for all Cities within 6 tiles of the City in which they are built, i.e. not within 6 tiles of the individual Powerplants.
  
  
• Renewables would work exactly the same as before; i.e. they reduce how much power a city needs.
  
  
• Powerplants would provide +2 Production to the City in which they are built (or +4 Production). They would not provide any radial production bonuses (i.e. they only power other cities). Industrial Zones would also provide +2 Adjacency to Industrial Zones.
  
  
• The Industrial Zone would get two mutually exclusive Tier 3 Buildings. First, a Tech Hub. This provides additional production equal to the IZs current adjacency, plus additional production and science when powered. Second, an Automated Production Facility, which provides a regional production boost plus additional production and gold when powered, and is a pre-requisite for building Spaceship Parts and the GDR.

What are the advantages?

• Power would be more strategic. First, you’d now face too bottlenecks – not just having enough fuel to generate power, but also having enough Powerplants to turn all that fuel into power. Second, you’d have more placement issues – you’d have to decide whether to cluster PPs in one City (where they’re more vulnerable to a single attack) or spread them across multiple Cities, and you’d have to consider whether you can place them next to IZs for additional adjacency.
  
  
• The IZ could have more interesting building options.
  
  
• You’d play the map more. There would be more on the map, as Powerplants would be more distinct taking up their own space on the map.
  
  
• You’d gain another late game District, given there are currently very few new districts in the end game.