This is the 3181st most frequent Russian word.
мощностей
"Capacities" or "powers" (plural form).
In this sentence, 'мощностей' refers to the capacity or maximum functional power level of the energy system.
Энергетическая система достигла своих предельных мощностей.
The power system has reached its maximum capacities.
Here, 'мощностей' is used to denote the capability or scale of production that the factory can achieve.
Завод увеличил производственные мощности, чтобы справиться с растущим спросом.
The factory increased its production capacities to meet the growing demand.
In this context, 'мощностей' pertains to the electrical capacity needed for operating the new equipment.