# How does one estimate the electrical power of a power plant?

I have two related questions that I would like help on:

1. When a power plant creates power like the Hoover Dam, it can provide 2.07 GW of electrical power. My question is what does this mean? I assume from Faraday’s law that the induced voltage across the generator coil produces an current, and this combination (P = VI) is the output power. So in the case of the Hoover Dam, P = VI = 2.07 GW. I feel that this is naïve thinking but when I do a search to get more information, I am not able to find any. Can someone roughly sketch out how the electrical power of a power plant is computed?

2. If possible, what kind of voltages and currents are power plants producing before the Step Up transformers?

1.- A power plant has many components, but the main ones that determine the capacity it would be the generators connected to the turbines. Hoover Dam has 17 large turbines and two small ones. Generators usually are rated in:
Power (MVA or kVA),
Voltage (kV),
Speed (RPM), and
Frequency (Hz).

Basically you add up the plant capacity as the sum of each generator capacity.

2.- Hoover Dam has huge main turbines and generators, I have no specs for these, but typical modern Hydro Generators are smaller and have the following specs:
-Synchronous type.
-Allow Vertical or Horizonal operation.
-Power: 2MVA to 40MVA.
-Speed: 150 to 900 RPM.
-Voltage: 3kV to 13.8kV.
-Frequency: 50Hz or 60Hz.
-Allow parallel connection and have Voltage Regulation.
-Power Factor control and Reactive Power control to allow connection to large grids.

For 1, you are spot on. The output voltage and current are multiplied to get the power. Numbers in the press are often optimistic. It may be a peak power, rather than one that can be sustained if they were willing to release enough water over a long period.