( Romm ( ( is ( ( an expert ) ( on ( ( ( ( ( ( ( ( clean energy ) , ) ( advanced vehicles ) ) , ) ( energy security ) ) , ) and ) ( greenhouse ( gas mitigation ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Romm)) (VP (VBZ is) (NP (NP (DT an) (NN expert)) (PP (IN on) (NP (NP (JJ clean) (NN energy)) (, ,) (NP (JJ advanced) (NNS vehicles)) (, ,) (NP (NN energy) (NN security)) (, ,) (CC and) (NP (NN greenhouse) (NN gas) (NN mitigation)))))) (. .)))
Romm is an expert on clean energy, advanced vehicles, energy security, and greenhouse gas mitigation.
(ROOT (S (NP (JJ Geothermal) (NN energy) (NN energy)) (VP (VP (VBZ is) (ADJP (JJ clean))) (CC and) (VP (VBZ does) (RB not) (VP (VB release) (NP (NN greenhouse) (NNS gases))))) (. .)))