Texas PUC Rule 25.211: Distributed Generation Interconnection Guide

Key Takeaways

• Texas PUC Rule 25.211 governs on-site distributed generation up to 10 MW at less than 60 kV.
• A utility may not charge a pre-interconnection study fee for pre-certified units up to 500 kW.
• Interconnection for pre-certified equipment must take place within four weeks.
• Changes in ownership or cessation of operations must be reported within 14 days.

What is Texas PUC Rule 25.211?

Texas PUC Rule 25.211, formally titled "§25.211. Interconnection of On-Site Distributed Generation (DG)," outlines the terms and procedures for connecting on-site distributed generation facilities to the electric grid in Texas. This rule applies to facilities with a maximum capacity of ten megawatts (MW) or less, connected at a voltage less than 60 kilovolts (kV) (August 2026). It establishes guidelines for interconnection studies, timelines, and operational requirements.

The rule aims to standardize the process for integrating smaller-scale power generation, such as solar or wind, into the existing utility infrastructure. It covers various aspects, from initial application to ongoing reporting.

Key Provisions of Texas PUC Rule 25.211

The following table details the primary provisions of Texas PUCT Substantive Rule §25.211, as of August 2026. These requirements dictate how distributed generation facilities interact with the Texas electric grid.

| Stabilized System Disturbance Definition | "following a disturbance, the system returns to the normal range of voltage and frequency for a duration of two minutes or a shorter time" | Figures as of August 2026.

How are interconnection applications processed in Texas?

The process for interconnecting distributed generation in Texas involves specific timelines and fee structures. For facilities using pre-certified equipment, interconnection is scheduled to occur within four weeks of the utility receiving a complete application (August 2026). For facilities that do not use pre-certified equipment, this timeline extends to six weeks (August 2026).

Pre-interconnection study fees are waived under certain conditions. A utility may not charge a study fee for pre-certified distributed generation units up to 500 kW (August 2026). Additionally, for facilities with inverter systems under 20 kW connected to a secondary network, no pre-interconnection study fee is assessed (August 2026). The pre-interconnection study itself must take no more than four weeks to complete (August 2026).

We verified these provisions by reviewing the Public Utility Commission of Texas (PUCT) Substantive Rule §25.211 document on August 23, 2026.

What are the limits for distributed generation in Texas?

Texas PUC Rule 25.211 sets several limits to ensure grid stability and safety. Distributed generation facilities are capped at ten megawatts (MW) and must connect at a voltage less than 60 kilovolts (kV) (August 2026).

Further restrictions apply to feeder export and short circuit contributions. A facility may not export more than 15% of the total load on a single radial feeder (August 2026). It also cannot contribute more than 25% of the maximum potential short circuit current on a single radial feeder (August 2026).

For secondary networks, utilities must approve applications unless the total distributed generation on affected feeders, including the new facility, represents more than 25% of the secondary network's total load (August 2026). These limits are in place to prevent overloading and maintain grid reliability.

Understanding Reporting and Maintenance Requirements

Owners of distributed generation facilities in Texas have ongoing responsibilities under Rule 25.211. Any change in ownership or the cessation of operations for an interconnected facility must be reported to the utility within 14 days of the change (August 2026).

Utilities also have obligations regarding maintenance. They must provide seven business days prior written notice for service interruptions due to routine maintenance, repairs, or system modifications (August 2026). If a facility is found to be out of compliance, the utility must verify its restoration within two business days of the customer notifying them of compliance (August 2026).

Utilities are also required to file an annual distributed generation interconnection report with the commission by March 30 of each year, covering the preceding calendar year (August 2026).

Important Considerations for Texas DG Owners

While Texas PUC Rule 25.211 provides a framework for interconnection, some nuances exist. Electric cooperatives are generally exempt from this rule, with the exception of subsection (o) which pertains to distributed natural gas generation. This means that if you are connecting to an electric cooperative, their specific interconnection rules may differ from those outlined in §25.211.

Additionally, if the estimated cost of upgrades exceeds 5% of the initial estimate, you have the right to petition the Public Utility Commission of Texas. This provision offers a mechanism for recourse if upgrade costs become unexpectedly high. We have not verified the specific process for such petitions, so we do not publish it.

Navigating interconnection rules can be complex. For broader context on system planning, you may find our guides on Kentucky PSC Net Metering Rules or Delaware PSC Net Metering helpful, though specific rules vary by state. If you are planning a new solar installation, using a solar sizing tool can help you determine your energy needs before engaging with utility interconnection processes.