Mezue ahịrịokwu na-esonụ: N'afọ 1993, Union Electric lụrụ ọgụ a
Idei mmiri nke na-eme kemgbe afọ 500 n'obodo ukwu St. Louis site n'osimiri Missouri na Mississippi. N'afọ 1994, Union Electric kesara onyinye Edison nke ụlọ ọrụ ahụ na Midwest Power Systems, Inc., nke Des Moines, Iowa, maka ọrụ ha na-enye ndị ahịa ọrụ eletrik n'oge ọdachi idei mmiri nke 1993.