( ( ( The rate ) ( of ( energy usage ) ) ) ( ( is power ) . ) )
(ROOT (S (NP (NP (DT The) (NN rate)) (PP (IN of) (NP (NN energy) (NN usage)))) (VP (VBZ is) (NP (NN power))) (. .)))
The rate of energy usage is power .
(ROOT (S (NP (NP (DT The) (NN rate)) (SBAR (IN that) (S (NP (NN energy)) (VP (VBZ is) (VP (VBN released)))))) (VP (VBZ is) (VP (VBN known) (PP (IN as) (NP (NN power))))) (. .)))