The power plant is frequently used by experienced players to quickly expand in the early game, as nearly six can be built with the starting funds. In the short run, Power Plants are very efficient, and can be used to expand across the map very quickly.
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 Power 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. In addition, Power Plants are highly recommended early game, because you will be able to create more than one. 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.