Interconnection is the utility's process, not the city's. It runs on its own application, its own review, its own agreement, and its own clock — and finishing the city inspection means nothing to the utility until its paperwork is done. In Texas, which process you're in depends entirely on who owns the wires at the meter.
First question on every job: who owns the wires?
Texas has three fundamentally different regimes, and the address decides which one you're in:
Transmission and distribution utilities (TDUs) — Oncor, CenterPoint, AEP Texas, TNMP. These serve the deregulated ERCOT areas where the homeowner picks a retail electric provider (REP). The TDU owns the wires and the meter and runs interconnection; the REP handles billing and any surplus buyback. Interconnection here is governed by PUCT rules.
Municipal utilities — Austin Energy, CPS Energy (San Antonio), Garland Power & Light, and others. The city utility is wires, billing, and program rules all in one. Each muni writes its own interconnection standards, and some are notably stricter than the PUCT framework — see Austin Energy and CPS Energy.
Electric cooperatives — Pedernales, CoServ, Bluebonnet, and dozens more across rural and exurban Texas. Co-ops are largely exempt from the PUCT's interconnection rule (only a narrow slice of it applies to them), so each co-op's board-approved policy is the rulebook. Same house, one mile past the TDU boundary, completely different process — details in Interconnecting in Co-op Territory.
Getting this wrong at the sales stage is expensive. The interconnection application goes to whoever owns the distribution wires serving the property — never to the REP.
The rules underneath TDU interconnection
Two PUCT substantive rules govern distributed generation with the investor-owned utilities: §25.211 (terms and process for interconnection and parallel operation) and §25.212 (technical requirements). They exist to implement PURA §39.101(b)(3), which entitles Texas electric customers to access on-site distributed generation. A few pieces installers should actually know:
- The framework covers on-site DG with utility review of the application, a signed interconnection agreement, and defined grounds for disconnection (including non-compliance with §25.212's technical requirements).
- Utilities can't assess distribution or transmission charges against a customer for exporting energy under the rule.
- Capacity at the point of common coupling is capped (the rule contemplates systems up to 10 MW — far beyond residential scope, which is why residential reviews are typically screens rather than studies).
Worth watching: the PUCT has been overhauling these rules through its DER rulemaking (Project 54233), including proposals that restructure §§25.210–25.212 and set standards by system size. When it lands, application forms and timelines will shift — we track it in The PUCT's DER Interconnection Overhaul.
The standard sequence (TDU territory)
- Application. Filed by the installer through the utility's portal with the technical package — one-line diagram, site layout, inverter and module make/model. Certified equipment (UL 1741-listed inverters per IEEE 1547) is what makes a system eligible for the streamlined path.
- Utility review. A screen for grid impact; small residential systems rarely trigger a study. Objections come back as deficiencies — the interconnection equivalent of plan-review comments.
- Permit and inspection first. TDUs generally require the installation to be permitted and inspected (where applicable) before finalizing interconnection.
- Interconnection agreement. Signed by the customer and the utility. Unsigned agreements are one of the most common silent delays — the document sits in a homeowner's inbox while everyone thinks the utility is "still reviewing."
- Permission to Operate. The utility issues PTO, then reprograms or swaps the meter to measure exports. Energizing before PTO violates the utility's tariff and PUCT rules — consequences and timelines in our PTO guide.
No net metering — and why that's a sales conversation, not an interconnection problem
Texas has no statewide net metering mandate. In deregulated territory, export compensation depends on which REP buyback plan the homeowner chooses; in muni and co-op territory, it's whatever that utility's program says. Interconnection paperwork is identical either way, but a homeowner who signs a no-buyback REP contract right before PTO can erase their export value — flag it early. Full picture: Texas Doesn't Have Net Metering.
Running interconnection as an operation
Every utility has different forms, portals, signature requirements, and quirks — and a mid-size installer might be working six of them at once. The failure mode is the same as permitting: not slow utilities, but applications sitting in "waiting on someone" states nobody is watching. Whether you solve it with a dedicated coordinator or with software, every job needs a visible interconnection stage, an owner, and an aging alarm. TexPTO tracks permit and interconnection milestones side by side per job, because homeowners don't care which bureaucracy is slow — they care that the system on their roof isn't on yet.
FAQ
Is interconnection the same as the permit? No. The permit is the city's approval to build; interconnection is the utility's approval to connect and operate in parallel with the grid. You need both, and they run on separate clocks.
Who submits the interconnection application in Texas? Almost always the installer, on the homeowner's behalf — but the homeowner signs the application and the interconnection agreement.
Can a Texas utility refuse to interconnect solar? For compliant, certified residential systems in TDU territory, PUCT rules entitle customers to interconnection. Utilities can require corrections, and in rare cases grid constraints (like an overloaded transformer) add steps — see Transformer Limits.
Does interconnection cost anything? For certified residential-scale systems with the major TDUs, typically no study fee. Larger or non-certified systems can trigger study fees and upgrade costs.
Sources
- PUCT Substantive Rule §25.211, Interconnection of On-Site Distributed Generation: https://www.puc.texas.gov/agency/rulesnlaws/subrules/electric/25.211/25.211.pdf
- PUCT §25.211 rule history and forms: https://www.puc.texas.gov/agency/rulesnlaws/subrules/electric/25.211/Default.aspx
- PUCT DER rulemaking, Project 54233 (public comments): https://interchange.puc.texas.gov/Documents/54233_107_1513929.PDF
- CenterPoint Energy DER Application Tariff (example TDU tariff implementing 25.211/25.212): https://www.centerpointenergy.com/en-us/Documents/CenterPoint%20Energy%20DER%20Application%20Tariff.pdf
General information, not legal advice. Confirm current requirements with the serving utility.