By your description it sounds you guys in Iowa have a regulated market. There you have a vertically integrated electric utility company who does everything from generation to line maintenance and billing with oversight from a public regulator.

In a deregulated electric market you have separate generator companies who sell wholesale electricity to retail energy suppliers who sell it on to end customers. Transmission companies maintain the grid infrastructure and they are paid by the other participants for this service. This scheme when it works right can result in more competition and thus better efficiencies.

This page seems to explain it quite nicely: https://infocastinc.com/market-insights/solar/regulated-dere...