Larger version of the Power Plant, this income building generates 16 p/m and pays itself off after 10 minutes. Two of these are required to be able to build a Nuclear Silo.
Being a solid building with 300 hitpoints, 14 p/m generation and a relatively short pay-off time of 10 minutes, the Nuclear Plant is an excellent mid-game income building.
Power Plant, Nuclear Plant, or Fusion Plant? Edit
Sometimes it's hard to decide which one to build. If you build a Fusion Plant at an energy crystal and it is destroyed ten minutes later, it was not a profitable investment. However, if you had made a normal power plant, you would have made some money from that. What plant should you build at each energy crystal?
Above is a graph of the production speeds of each type of plant, as well as their cost. The x-axis is minutes, and the y-axis is total profits. The blue line represents the Power Plant, the yellow line represents the Nuclear Plant, and the red line represents the Fusion Plant. Point A represents when the Nuclear Plant is more effective than the Power Plant, and is at 18.75 minutes in. Point B is when the Fusion Plant is more effective than the Power Plant, and is at 23.5 minutes. Point C is when the Fusion Plant is more effective than the Nuclear Plant, and is at 26.67 minutes. Point D is where the Power Plant would make a profit (6.5 minutes), Point E is where the Nuclear Plant would make a profit (10 minutes), and point F is where the Nuclear Plant would make a profit (15 minutes).
What does this data mean? If you can protect an energy crystal for more than 7 minutes, but less than 19, then you should build a regular Power Plant. If you can protect an energy crystal for more than 19 minutes, but less than 27, it's recommended that you build a Nuclear Plant. If you can protect an energy crystal for more than 27 minutes, it's recommended that you build a Fusion Plant.
However, there are other factors to take into consideration. For example, the Nuclear Plant does not have a turret that can shoot things, which means that it can not defend itself or protect itself against hostile Stealth Bombers. Also, Nuclear Plants are required for the creation of the Nuclear Silo, and it is advised that a player has two by the 60 minute mark if they want to create ICBMs. In addition, Nuclear Plants are not really recommended early game, because you will be able to create only two with the starting funds. One at a central, protected base may be appropriate, but Power Plants are more appropriate for other places. All of these factors must be taken into consideration when choosing what plant to build.
In the end, the general rule is this: if you can protect it for only a small amount of time, make a Power Plant. If you can protect it for a medium amount of time, make a Nuclear Plant. If you can protect it for a long amount of time (for example, if you were making it at your base), make a Fusion Plant.