Which side of the line your address falls on
AEP Texas is a transmission and distribution utility. It owns the poles and wires and reads the meter, but it does not sell you electricity and it does not set your export credit. In its territory you pick a retail provider, and whether you are paid for exports depends entirely on the plan you choose.
Magic Valley Electric Cooperative is a different animal. It is owned by its members, serves counties across the Valley including Hidalgo County, and is not part of the deregulated retail market, so there is no provider to select and no plan to compare.
This is not a distinction you can resolve from a city name. Service boundaries do not follow municipal boundaries, and neighbouring streets can fall on opposite sides of one.
So establish it first, before you take a quote seriously. Look at a current electricity bill and identify who bills you and who delivers. Everything else in the project follows from that answer.
On the cooperative, surplus does not carry over
Magic Valley does have net metering in the literal sense. The cooperative describes a net meter as allowing energy to flow in both directions, so that overproduction during the day flows back through the meter and turns it backwards.
What it does not do is bank or buy that surplus. The cooperative states plainly that it does not buy back or credit forward any excess energy produced, and that energy is calculated and billed within a billing cycle, with excess production not carried over to the next.
That is a much harder constraint than it first sounds. Within a billing cycle your generation offsets your consumption. At the end of the cycle, anything left over is simply gone: not paid for, not credited, not carried forward.
Members also still receive a monthly bill covering the customer charge and applicable fees and taxes, even in a month when the system generated everything the household used. Solar reduces the energy portion of the bill, not the bill itself.
What that does to the right system size
If surplus is lost at the end of each billing cycle, then capacity that produces beyond your consumption in that cycle is worth nothing. Not less, nothing. That puts a hard ceiling on the useful size of a cooperative connected system.
It also removes seasonal banking. In markets with annual settlement, a long productive summer builds credit that carries into winter. Here each cycle stands alone, so a summer surplus cannot be used to cover a winter shortfall.
The design that follows is smaller than a roof would hold and sized against your lowest consumption months rather than your average, because that is the period where oversizing starts wasting generation.
Ask any installer working on a cooperative connection to model the system month by month against your own consumption, and to say how much annual generation their model expects to be lost. If they cannot answer, the design was not built for this utility.
The paperwork on both sides, and the exemption
The cooperative requires a completed application and a signed agreement for review, with separate distributed generation packets for systems of 50 kW and under and for larger ones, and it reserves the right to deny an installation if safety measures are not addressed.
In AEP Texas territory the process differs and the interconnection runs through the delivery utility while your compensation comes from your retail plan. Ask your installer which of the two processes they are running for you, and confirm they have done it before.
Texas Tax Code Section 11.27 exempts 100 percent of the appraised value an installed solar energy device adds to your home, and it applies either way. Form 50-123 goes to your county appraisal district with a deadline generally of 30 April, and it is not automatic.
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 does not receive it. Section 48E survives at 30 percent for third-party owners, so a lease or PPA provider may still claim it.