I've mentioned Central West Public Service Co. / Central Electric & Telephone Co. / Central Gas & Electric Co. / Western Power & Gas Co. at various times

I found this page recently:
The above companies ARE ALL THE SAME OUTFIT - just different times!

Here is a list of CWPS' original electric properties in the Dakotas and Nebraska as of 1926; other towns would have been added to this list before the various groups were sold off through the early 1960s.

South Dakota:
Hot Springs (Mountain States Power by 1930s, today Black Hills Power)
Britton (sold to Otter Tail Power in 1928)
Kennebec, Murdo, Oacoma, Presho, (sold to West Central REC in 1958)
Artesian, Canova, Carthage, Fedora, Forestburg, Junius, Ramona, Roswell, Vilas, Winfred (sold to Northern States Power in 1961)
Amherst, Alpena, Freeman (sold to Northwest Public Service in the 1920s)
Chamberlain, Cuthbert, Kimball, Lane, Mt. Vernon, Stickney, White Lake, Woonsocket (sold to Northwest Public Service in 1961)
Howard and Plankinton evidently "went muni" at some point.

Albion, Jackson, Crystal Lake, Saunders Beach
(presumably sold to their local PPDs in the 1940s)

North Dakota:
Bowman, Reeder, Hettinger (sold to Montana-Dakota Power in 1928)
Buffalo, Starkweather, Tower City (traded to Otter Tail in 1928 for Devils Lake phone system)
Gackle, Medina, Streeter (among the 18 towns sold to Otter Tail in 1943)