a highly energetic and indefatigable person
"Sarah is such a powerhouse at work; she never seems to tire even after running three meetings back-to-back."
a team considered to be the best of its class
"The new basketball squad has quickly become a powerhouse in the league, leaving every other competitor trailing behind."
an electrical generating station
"The new powerhouse at the river dam began supplying electricity to the entire valley earlier than expected."
A power station.
"After the hurricane damaged our local grid, engineers rushed to repair the aging powerhouse that supplies electricity to the entire city."