A 1973 law decides who sells you electricity
The Territorial Electric Service Act was enacted on 29 March 1973 to assure the most efficient, economical and orderly rendering of retail electric service within the state and to avoid duplication of electric lines. Under it, every geographic area was either assigned to an electric supplier or declared unassigned.
The practical effect is that a residential customer has no choice. Customers with connected loads of less than 900 kW must take electricity from the franchised supplier for their area. Only a customer with a load of 900 kW or more, located within the corridors of a supplier lines, may have a choice of suppliers, which is a threshold no house reaches.
Georgia has three kinds of supplier and they are not interchangeable. Georgia Power is the large investor-owned utility; there are 42 electric membership corporations; and there are 47 cities plus Crisp County in the Municipal Electric Authority of Georgia, along with several cities operating independently.
Boundaries follow the 1973 assignments rather than city limits or subdivision names, so they are invisible from the street. Two houses a few hundred metres apart can be on different suppliers with materially different solar terms.
Who sets the rate, and who does not
This matters more than it sounds, because the supplier type determines who has authority over your terms. The Public Service Commission has full rate-making jurisdiction over the investor-owned companies, and that is where the familiar Georgia Power solar rules come from.
For the others it is different. The Commission has limited authority with respect to cooperatives and municipals, who must file their rates with the Commission. Filing a rate and having it set are not the same thing, and the distinction is the whole point.
So if you are served by Marietta Power or by Cobb EMC, your solar terms are decided by a municipal board or a cooperative board rather than by the PSC. There is no Commission proceeding behind them and no Commission decision to appeal to.
That is not automatically worse. Cooperative and municipal terms are sometimes better than the regulated alternative. It does mean the terms are local, and that they can be revised locally, so ask how long any figure you are quoted is guaranteed for.
How to establish which supplier you are on
Look at a current electricity bill. The name at the top is the answer, and it takes a minute. Do not rely on a postal address, a neighbourhood name, or on what a neighbour tells you, because assignment boundaries do not respect any of those.
Then get that supplier own document. Ask for the distributed generation or net metering rider by name, in writing, rather than accepting a summary. A rider is a short document and it contains the numbers that decide your project.
Ask three things of it specifically: the rate paid for exported energy and what basis it is calculated on, any recurring monthly charge that applies to solar customers, and any one off interconnection fee.
Then ask your installer which supplier and which rider their projection assumed. If they cannot name both, the model is not about your house, and in a county with more than one supplier that is a real risk rather than a theoretical one.
The parts that do not vary by supplier
Self-consumption is the same arithmetic whoever bills you. Electricity used in the moment it is generated avoids a purchase at your full retail rate, and every Georgia export arrangement pays less than retail, so using your own generation is always worth more than sending it out.
That points to the same design conclusion across all three supplier types: size against your daytime draw rather than your annual total, and treat export credits as the smaller and less certain part of the return.
The federal position is also uniform. The 30 percent Residential Clean Energy Credit under Section 25D expired for property placed in service after 31 December 2025, so a cash or loan purchase now receives no federal credit.
Section 48E survives at 30 percent for third-party owners under leases and power purchase agreements, so ask what a provider claims and what reaches you in the rate.