Start with the utility territory, not the city label
The service-territory check answers the first Fulshear question: who owns the delivery relationship at the meter? For the addresses covered by this guide, that context is CenterPoint Energy Houston Electric. Retail competition occurs on top of that delivery system, so the customer can select a REP without changing the TDU.
Municipal boundaries and electric boundaries are different datasets. A Fulshear mailing address near a territory edge can require a separate verification step. Confirming the utility before comparing price plans is faster than discovering at enrollment that the selected offer is unavailable.