( Charge ( ( ( ( ca n't ) spontaneously ) ( ( flow ( from ( ( lower voltage ) ( to ( higher voltage ) ) ) ) ) ( because ( that ( would ( mean ( that ( ( its ( electrostatic ( potential energy ) ) ) rises ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Charge)) (VP (MD ca) (RB n't) (ADVP (RB spontaneously)) (VP (VB flow) (PP (IN from) (NP (NP (JJR lower) (NN voltage)) (PP (TO to) (NP (JJR higher) (NN voltage))))) (SBAR (IN because) (S (NP (DT that)) (VP (MD would) (VP (VB mean) (SBAR (IN that) (S (NP (PRP$ its) (JJ electrostatic) (JJ potential) (NN energy)) (VP (VBZ rises)))))))))) (. .)))
Charge can't spontaneously flow from lower voltage to higher voltage because that would mean that its electrostatic potential energy rises.
(ROOT (S (NP (NNP Voltage)) (VP (VP (VBZ is) (RB not) (NP (NP (DT the) (JJ same)) (PP (IN as) (NP (NN energy))))) (, ,) (CC but) (VP (VBZ means) (NP (NP (DT the) (NN energy)) (PP (IN per) (NP (NN unit) (NN charge)))))) (. .)))