RE:What % of Crew'sCrew does not separate the ethane, instead they are credited for the extra heat content.( A large part of the reason that they get a 24 % bonus on NG prices. !!) The problem with ethane is that it is in a gaseous state. SO a separate pipeline is necessary to get it to a polyethelyne producer !! This is part of the reason that Alliance and Dawn trade at higher prices as gas plants there can separate the c2's c3's c4's etc. and sell them to nearby petrochemical producers.
There may be other alternatives for Crew , but I have been retired too long. Perhaps fresher minds can fill us in !!