'Energy' and 'power' are often confused, but aren't the same. Why do we say 'power plants' instead of energy plants'?

Both are important capabilities of a generator to keep the lights on.

Explanation:Power plants do provide both energy and power. Both are important capabilities of a generator to keep the lights on. And, in fact, power plants are rated, not by how much energy they produce, but by how much power they can produce, because if the grid does not have enough power generation capacity, it won’t work. It is arguably the more important parameter to specify in an electrical generation facility.

So, you could probably call them either power or energy plants. I do not know the history of why we chose to use power.