|(a) Application. Unless the context indicates otherwise,
this section and §25.212 of this title (relating to Technical
Requirements for Interconnection and Parallel Operation of On-Site
Distributed Generation) apply to an electric utility for all purposes
except to the extent preempted by federal law. The only part of this
section that applies to electric cooperatives is subsection (o) of
(b) Purpose. The purpose of this section includes stating
the terms and conditions that govern the interconnection and parallel
operation of both on-site distributed generation in order to implement
Public Utility Regulatory Act (PURA) §39.101(b)(3) and a natural
gas distributed generation facility in order to implement PURA §35.036.
Sales of power by on-site distributed generation and natural gas distributed
generation in the intrastate wholesale market are subject to §§25.191-25.203
of this title (relating to Open-Access Comparable Transmission Service
for Electrical Utilities in the Electric Reliability Council of Texas).
(c) Definitions. The following words and terms when
used in this section and §25.212 of this title shall have the
following meanings, unless the context indicates otherwise:
(1) Application for interconnection and parallel operation
or application--The form of application prescribed in subsection (q)
of this section.
(2) Company--An electric utility operating a distribution
(3) Customer--Any entity interconnected to the company’s
utility system for the purpose of receiving or exporting electric
power from or to the company’s utility system.
(4) Distributed natural gas generation facility--A
facility installed on the customer’s side of the meter that
uses natural gas to generate not more than 2,000 kilowatts of electricity.
(5) Facility--An electrical generating installation
consisting of one or more on-site distributed generation units, including
a distributed natural gas generation facility. The total capacity
of the installation’s on-site distributed generation units may
exceed ten megawatts (MW); however, no more than ten MW of the installation’s
capacity will be interconnected at any point in time at the point
of common coupling under this section.
(6) Interconnection--The physical connection of distributed
generation to the utility system in accordance with the requirements
of this section so that parallel operation can occur.
(7) Interconnection agreement--The form of agreement
prescribed in subsection (p) of this section. The interconnection
agreement sets forth the contractual conditions under which a company
and a customer agree that one or more facilities may be interconnected
with the company’s utility system.
(8) Inverter-based protective function--A function
of an inverter system, carried out using hardware and software, that
is designed to prevent unsafe operating conditions from occurring
before, during, and after the interconnection of an inverter-based
static power converter unit with a utility system. For purposes of
this definition, unsafe operating conditions are conditions that,
if left uncorrected, would result in harm to personnel, damage to
equipment, unacceptable system instability or operation outside legally
established parameters affecting the quality of service to other customers
connected to the utility system.
(9) Network service--Network service consists of two
or more utility primary distribution feeder sources electrically tied
together on the secondary (or low voltage) side to form one power
source for one or more customers. The service is designed to maintain
service to the customers even after the loss of one of these primary
distribution feeder sources.
(10) On-site distributed generation (or distributed
generation)--An electrical generating facility located at a customer’s
point of delivery (point of common coupling) of ten megawatts (MW)
or less and connected at a voltage less than 60 kilovolts (kV) which
may be connected in parallel operation to the utility system.
(11) Parallel operation--The operation of on-site distributed
generation while the customer is connected to the company’s
(12) Point of common coupling--The point where the
electrical conductors of the company utility system are connected
to the customer’s conductors and where any transfer of electric
power between the customer and the utility system takes place, such
as switchgear near the meter.
(13) Pre-certified equipment--A specific generating
and protective equipment system or systems that have been certified
as meeting the applicable parts of this section relating to safety
and reliability by an entity approved by the commission.
(14) Pre-interconnection study--A study or studies
that may be undertaken by a company in response to its receipt of
a completed application for interconnection and parallel operation
with the utility system. Pre-interconnection studies may include,
but are not limited to, service studies, coordination studies and
utility system impact studies.
(15) Stabilized--A company utility system is considered
stabilized when, following a disturbance, the system returns to the
normal range of voltage and frequency for a duration of two minutes
or a shorter time as mutually agreed to by the company and customer.
(16) Tariff for interconnection and parallel operation
of distributed generation--The tariff for interconnection and parallel
operation of distributed generation prescribed in subsection (q) of
(17) Unit--A power generator.
(18) Utility system--A company’s distribution
system below 60 kV to which the generation equipment is interconnected.
(d) Terms of Service.
(1) Distribution line charge. No distribution line
charge shall be assessed to a customer for exporting energy to the
(2) Interconnection operations and maintenance costs.
No charge for operation and maintenance of a utility system’s
facilities shall be assessed against a customer for exporting energy
to the utility system.
(3) Transmission charges. No transmission charges shall
be assessed to a customer for exporting energy. For purposes of this
paragraph, the term transmission charges means transmission access
and line charges, transformation charges, and transmission line loss
(4) New or amended interconnection agreements. A new
or amended interconnection agreement entered into 30 or more days
after the commission’s approval of an electric utility’s
compliance tariff filed pursuant to paragraph (5) of this subsection
shall meet the requirements of this section.
(5) Tariffs. Not later than 30 days after the effective
date of this amended section, an electric utility shall file with
the commission for approval tariff amendments to comply with this
amended section, including subsections (p) and (q) of this section.
An electric utility shall include in its tariff the fees for interconnection
studies. An electric utility that sells electricity shall also include
back-up, supplemental, and maintenance power services for distributed
generation in its tariff.
(e) Disconnection and reconnection. A utility may disconnect
a distributed generation unit from the utility system under the following
(1) Expiration or termination of interconnection agreement.
The interconnection agreement specifies the effective term and termination
rights of company and customer. Upon expiration or termination of
the interconnection agreement with a customer, in accordance with
the terms of the agreement, the utility may disconnect customer’s
(2) Non-compliance with the technical requirements
specified in §25.212 of this title. A utility may disconnect
a distributed generation facility if the facility is not in compliance
with the technical requirements specified in §25.212 of this
title. Within two business days from the time the customer notifies
the utility that the facility has been restored to compliance with
the technical requirements of §25.212 of this title, the utility
shall have an inspector verify such compliance. Upon such verification,
the customer in coordination with the utility may reconnect the facility.
(3) System emergency. A utility may temporarily disconnect
a customer’s facility without prior written notice in cases
where continued interconnection will endanger persons or property.
During the forced outage of a utility system, the utility shall have
the right to temporarily disconnect a customer’s facility to
make immediate repairs on the utility’s system. When possible,
the utility shall provide the customer with reasonable notice and
reconnect the customer as quickly as reasonably practical.
(4) Routine maintenance, repairs, and modifications.
A utility may disconnect a customer or a customer’s facility
with seven business days prior written notice of a service interruption
for routine maintenance, repairs, and utility system modifications.
The utility shall reconnect the customer as quickly as reasonably
possible following any such service interruption.
(5) Lack of approved application and interconnection
agreement. In order to interconnect distributed generation to a utility
system, a customer must first submit to the utility an application
for interconnection and parallel operation with the utility system
and execute an interconnection agreement on the forms prescribed by
the commission. The utility may refuse to connect or may disconnect
the customer’s facility if such application has not been received
(f) Incremental demand charges. During the term of
an interconnection agreement a utility may require that a customer
disconnect its distributed generation unit and/or take it off-line
as a result of utility system conditions described in subsection (e)(3)
and (4) of this section. Incremental demand charges arising from disconnecting
the distributed generator as directed by company during such periods
shall not be assessed by company to the customer.
(g) Pre-interconnection studies for non-network interconnection
of distributed generation. A utility may conduct a service study,
coordination study or utility system impact study prior to interconnection
of a distributed generation facility. In instances where such studies
are deemed necessary, the scope of such studies shall be based on
the characteristics of the particular distributed generation facility
to be interconnected and the utility’s system at the specific
proposed location. By agreement between the utility and its customer,
studies related to interconnection of on-site distributed generation
on the customer’s premises may be conducted by a qualified third
(1) Distributed generation facilities for which no
pre-interconnection study fees may be charged. A utility may not charge
a customer a fee to conduct a pre-interconnection study for pre-certified
distributed generation units up to 500 kW that export not more than
15% of the total load on a single radial feeder and contribute not
more than 25% of the maximum potential short circuit current on a
single radial feeder.
(2) Distributed generation facilities for which pre-interconnection
study fees may be charged. Prior to the interconnection of a distributed
generation facility not described in paragraph (1) of this subsection,
a utility may charge a customer a fee to offset its costs incurred
in the conduct of a pre-interconnection study. In those instances
where a utility conducts an interconnection study the following shall
(A) The conduct of such pre-interconnection study shall
take no more than four weeks;
(B) A utility shall prepare written reports of the
study findings and make them available to the customer;
(C) The study shall consider both the costs incurred
and the benefits realized as a result of the interconnection of distributed
generation to the company’s utility system; and
(D) The customer shall receive an estimate of the study
cost before the utility initiates the study.
(h) Network interconnection of distributed generation.
Certain aspects of secondary network systems create technical difficulties
that may make interconnection more costly to implement. In instances
where customers request interconnection to a secondary network system,
the utility and the customer shall use best reasonable efforts to
complete the interconnection and the utility shall utilize the following
(1) A utility shall approve applications for distributed
generation facilities that use inverter-based protective functions
unless total distributed generation (including the new facility) on
affected feeders represents more than 25% of the total load of the
secondary network under consideration.
(2) A utility shall approve applications for other
on-site generation facilities whose total generation is less than
the local customer’s load unless total distributed generation
(including the new facility) on affected feeders represents more than
25% of the total load of the secondary network under consideration.