Texas Administrative Code
Title 30 - ENVIRONMENTAL QUALITY
Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY
Chapter 106 - PERMITS BY RULE
Subchapter W - TURBINES AND ENGINES
Section 106.513 - Natural Gas-Fired Combined Heat and Power Units

(1) This section applies to combined heat and power (CHP) units that are powered by pipeline-quality natural gas-fired engines, including turbines. This section also authorizes any fugitive components associated with a CHP unit authorized by this section.

(2) This section does not relieve the owner or operator from complying with any other applicable provision of the Texas Health and Safety Code, Texas Water Code, rules of the Texas Commission on Environmental Quality (TCEQ), or any additional local, state, or federal laws or regulations. Emissions that exceed the limits in this section are not authorized and are violations.

(1) Combined heat and power (CHP) unit--A collection of facilities and other equipment that generally consists of an electric generating unit (EGU) and a means of extracting energy from the EGU for useful purposes other than electricity generation, such as heating or cooling. A CHP unit does not include facilities for generating additional electricity after the EGU. Equipment that is not a source of emissions itself but also extracts energy from the exhaust flow to create electricity is not a facility and may be used in addition to a CHP unit authorized by this section.

(2) Pipeline-quality natural gas--A naturally occurring fluid mixture of hydrocarbons (composed predominantly of methane, with lesser amounts of ethane, propane, nitrogen, carbon dioxide, and trace amounts of hydrogen sulfide) produced in geological formations beneath the Earth's surface that maintains a gaseous state at standard atmospheric temperature and pressure under ordinary conditions, and that is provided by a supplier through a pipeline. Pipeline-quality natural gas must either be composed of at least 70% methane by volume, or have a gross calorific value between 950 and 1,100 British thermal units (BTU) per standard cubic foot. Sour gas as defined in § 101.1 of this title (relating to Definitions) is not pipeline-quality natural gas for purposes of this section.

(1) A CHP unit must be registered with the commission using the appropriate PI-7 form or an approved electronic registration method before start of construction. A CHP unit at a residential location that generates less than 20 kilowatts(kW) of electricity does not require registration and does not have to meet any other requirements of this section except subsection (a) of this section and paragraph (2) of this subsection.

(2) For a CHP unit to be eligible for authorization under this section, the heat recovered must equal at least 20% of the total heat energy output of the CHP unit. This requirement must be met continuously based on any calendar week of operation except for no more than two weeks in a rolling 52-week period if operation of the EGU component is necessary due to lack of available electricity.

(3) No owner or operator of a CHP unit that is required to register under this section may begin construction and/or operation without first obtaining written approval from the executive director.

(4) Except for oxidation-reduction (three-way) catalysts on rich-burn engines, and oxidation catalyst controls as required by subsection (d)(3) or (4) of this section, add-on controls may not be used to comply with the emission standards of this section.

(5) Any individual CHP unit, or any group of units meeting paragraph (7)(B) of this subsection, may not exceed 15 megawatts (MW) in capacity.

(6) Only one permit by rule (PBR) for Natural Gas-Fired CHP Units per this section may be registered at a site.

(7) No more than one CHP unit may be authorized at a site under this section, except as follows:

(8) Notwithstanding fuel restrictions elsewhere in this section, during an emergency, this PBR authorizes the use of propane, liquefied petroleum gas, gasoline, diesel, or fuel oil as an approved fuel for not more than 720 hours in any 365-day period. This PBR also authorizes brief use of these emergency fuels as needed for purposes of maintenance or testing, for not more than two hours in any seven-day period.

(1) Notwithstanding paragraphs (2), (3), or (4) of this subsection, a CHP unit with a capacity less than 20 kW is not subject to a nitrogen oxides (NOX) or carbon monoxide (CO) emission standard, and is not subject to the requirement for an oxidation catalyst control device.

(2) A CHP unit or any combination of units with a total capacity greater than or equal to 20 kW, but less than or equal to 8 MW, must meet the following emission standards: 1.0 pound of NOX per megawatt-hour (lb NOX /MWh); and 9.0 lb CO/MWh.

(3) Except as provided in paragraph (4) of this subsection, a CHP unit or any combination of units with a total capacity greater than 8 MW must meet the following emission standards: 0.7 lb NOX /MWh; and 9.0 lb CO/MWh. A CHP unit or units under this paragraph must also be equipped with an oxidation catalyst control device that maintains a minimum of 70% control of volatile organic compounds (VOC) in the CHP unit exhaust stream.

(4) Any combination of CHP units with a total capacity greater than 8 MW that are at least 900 feet apart from one another must meet the following emission standards and control requirements. For the purposes of this paragraph, any group of units under subsection (c)(7)(B) of this section is considered to be one unit when determining whether subparagraph (A) or (B) of this paragraph applies.

(5) Compliance with the NOX standards above may be achieved by taking credit for the heat recovered from the combustion unit. Credit will be at the rate of 1.0 MWh for each 3.4 million BTU of heat recovered. In order to claim this credit for CHP for units not sold and certified as an integrated package by the manufacturer, the owner or operator must provide as part of the application documentation of the heat recovered, electric output, efficiency of the generator alone, efficiency of the generator including CHP, and the use for the non-electric output.

(1) Internal combustion engine-based CHP units (excluding turbines).

(2) Internal combustion engine-based CHP units and turbines. If the CHP unit is not certified to meet the emission standards of subsection (d) of this section by the manufacturer according to a United States Environmental Protection Agency (EPA) testing protocol, the unit must be tested within 90 days of startup for NOX and CO according to appropriate EPA reference methods, California Air Resources Board methods, or equivalent alternative testing methods approved by the executive director and in accordance with the appropriate procedures of the TCEQ Sampling Procedures Manual. Tests must consist of three runs with a minimum of 30 minutes for each run or longer if required by the reference method. All engine- and turbine-based CHP units designed to generate more than 375 kW must be retested by the above method after every 16,000 hours of operation, regardless of certification.

(3) All CHP units which are required by subsection (d)(3) or (4) of this section to have an oxidation catalyst control device shall be tested to verify compliance with the required 70% VOC control efficiency within 90 days of startup. In lieu of the above test, the 70% VOC control requirement shall be satisfied if the unit is tested for gaseous organic compounds and the reduction is at least 90%. The testing shall be conducted using EPA reference methods or equivalent alternative testing methods approved by the executive director and in accordance with the appropriate procedures of the TCEQ Sampling Procedures Manual. All units required to be equipped with an oxidation catalyst control device must also be retested after every 16,000 hours of operation.

(4) Except for rich-burn engines equipped with oxidation-reduction (three-way) catalysts, and units required to be equipped with an oxidation catalyst under subsection (d)(3) or (4) of this section, the uncontrolled source must demonstrate compliance with the emission standards in subsection (d) of this section.

(1) For the life of the CHP unit, the registration application and any additional representations made during the approval process to obtain the registration; and

(2) The owner or operator must keep the following records for at least two years and make them available to the TCEQ or any local pollution control program with jurisdiction upon request:

(1) This PBR authorizes all emissions from planned startup and shutdown activities associated with facilities that are authorized by this section.

(2) This PBR authorizes emissions from the following planned maintenance activities associated with facilities authorized by this section: routine maintenance including, but not limited to, filter changes, oxygen sensor replacements, overhauls, lubricant changes, spark plug changes, and emission control system maintenance.