Interconnection Standards

The Texas Public Utility Regulatory Act (PURA) of 1999 included a provision that “a customer is entitled to have access… to on-site distributed generation,” leading the Public Utility Commission of Texas (PUCT) to subsequently adopt interconnection standards. The PUCT’s Distributed Generation Interconnection Manual includes a review of safety and technical requirements of distributed generation installations; a copy of applicable rules, application procedures and forms; Texas utility contacts; and equipment pre-certification requirements.

System Capacity Requirements

Interconnection rules apply to electrical generating facilities (consisting of one or more on-site distributed-generation units) located at a customer’s point of delivery, with a maximum capacity of 10 megawatts (MW) of capacity interconnected at any point in time at the point of common coupling and connected at a voltage less than 60 kilovolts. Independent School District Solar Generation (ISD-SG) has no generation capacity limit for interconnection.

Equipment and operational requirements are differentiated based on connection type (single-phase or three-phase), paralleling mode and system size. An external disconnect device is required for all systems.

Distributed Renewable Generation (DRG) is defined as generation equipment with a capacity of 2 MW or less provided by renewable energy technology. Owners of a DRG system outside of the Electric Reliability Council of Texas (ERCOT) area are permitted to interconnect through a single meter if they have a qualifying facility with a design capacity of 50 kilowatts (kW) or less and the DRG is rated to produce an amount of electricity that is less than or equal to the amount of electricity the owner consumed in the year before installation of the DRG.

Process

Standardized interconnection applications and interconnection agreements are used. Pre-certification provisions allow for fast-track interconnection for DRG with a capacity of 500 kW or less. No pre-interconnection study fees are required for units up to 500 kW (under most circumstances), and study fees for larger systems are limited. The time limit for pre-interconnection studies and application approval or rejection is 4-6 weeks.

Owners of DRG and ISD-SG of 2 MW or less cannot be required to purchase additional liability insurance. Owners of DRG systems are required to provide proof that equipment carries a warranty against breakdown and undue degradation for a minimum of 5 years. Renewable Energy Certificates resulting from the operation of a DRG are property of the owner of the DRG.

Neither a retail electric customer that uses DRG nor the owner of the distributed renewable generation that the retail electric customer uses is classified an electric utility, power generation company, or retail electric provider and is not required to register with or be certified by the PUCT if at the time DRG is installed, the estimated annual amount of electricity to be produced by the distributed renewable generation is less than or equal to the retail electric customer’s estimated annual electricity consumption. However, a person that owns electric generating facility rated at 1 MW or more and generates electricity that is not intended to be sold at wholesale must register with the PUCT as a self-generator, and a person that owns an electric generating facility rated at 1 MW or more, does not own transmission or distribution facilities, and generates electricity that is intended to be sold at wholesale must register as a power-generation company.