( ( Coke ( which ( is ( similar ( to coal ) ) ) ) ) ( , ( ( is ( ( used ( as ( a ( fuel source ) ) ) ) ( by ( Energy Services ) ) ) ) . ) ) )
(ROOT (S (NP (NP (NNP Coke)) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (ADJP (JJ similar) (PP (TO to) (NP (NN coal)))))))) (, ,) (VP (VBZ is) (VP (VBN used) (PP (IN as) (NP (DT a) (NN fuel) (NN source))) (PP (IN by) (NP (NNP Energy) (NNPS Services))))) (. .)))
Coke which is similar to coal, is used as a fuel source by Energy Services.
(ROOT (S (NP (NNP Coal)) (VP (MD can) (VP (VB be) (VP (VP (VBN mined) (PP (IN from) (NP (NN earth)))) (CC and) (VP (VBN used) (PP (IN as) (NP (DT an) (NN energy) (NN source))))))) (. .)))