Tuhia he haere tonu mō tēnei wāhanga - I te tau 1993, i whawhai a Union Electric ki te waipuke 500-tau
i te rohe nui o St. Louis mai i nga awa nui o Missouri me Mississippi. I te tau 1994, i tohaina e Union Electric te Tohu Edison o te umanga me Midwest Power Systems, Inc., o Des Moines, Iowa, mo a raatau mahi ki te whakarato ratonga hiko ki nga kaihoko i te wa o te aitua waipuke 1993.