Generally, FGD systems tend to be constructed closer to the ground compared to SCR technology retrofits.
( Generally ( , ( ( FGD systems ) ( ( tend ( to ( be ( ( constructed ( closer ( to ( the ground ) ) ) ) ( compared ( to ( SCR ( technology retrofits ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (ADVP (RB Generally)) (, ,) (NP (NNP FGD) (NNS systems)) (VP (VBP tend) (S (VP (TO to) (VP (VB be) (VP (VBN constructed) (ADVP (RBR closer) (PP (TO to) (NP (DT the) (NN ground)))) (PP (VBN compared) (PP (TO to) (NP (NNP SCR) (NN technology) (NNS retrofits))))))))) (. .)))
SCR technology retrofits differ from FGD systems.
( ( SCR ( technology retrofits ) ) ( ( differ ( from ( FGD systems ) ) ) . ) )
(ROOT (S (NP (NNP SCR) (NN technology) (NNS retrofits)) (VP (VBP differ) (PP (IN from) (NP (NNP FGD) (NNS systems)))) (. .)))