NR 440.50(2)(i) (i) “Gas turbine model” means a group of gas turbines having the same nominal air flow, combustor inlet pressure, combustor inlet temperature, firing temperature, turbine inlet temperature and turbine inlet pressure.

NR 440.50(2)(j) (j) “ISO standard day conditions” means 288° Kelvin, 60% relative humidity and 101.3 kilopascals pressure.

NR 440.50(2)(k) (k) “Ice fog” means an atmospheric suspension of highly reflective ice crystals.

NR 440.50(2)(km) (km) “Lean premix stationary combustion turbine” means any stationary combustion turbine where the air and fuel are thoroughly mixed to form a lean mixture for combustion in the combustor. Mixing may occur before or in the combustion chamber. A unit which is capable of operating in both lean premix and diffusion flame modes is considered a lean premix stationary combustion turbine when it is in the lean premix mode, and it is considered a diffusion flame stationary combustion turbine when it is in the diffusion flame mode.

NR 440.50(2)(L) (L) “Natural gas” means a naturally occurring fluid mixture of hydrocarbons, such as methane, ethane, or propane, produced in geological formations beneath the earth’s surface that maintains a gaseous state at standard atmospheric temperature and pressure under ordinary conditions. Natural gas contains 20.0 grains or less of total sulfur per 100 standard cubic feet. Equivalents of this in other units are as follows: 0.068 weight percent total sulfur, 680 parts per million by weight (ppmw) total sulfur, and 338 parts per million by volume (ppmv) at 20 degrees Celsius total sulfur. Additionally, natural gas shall either be composed of at least 70% methane by volume or have a gross calorific value between 950 and 1100 Btu per standard cubic foot. Natural gas does not include the following gaseous fuels: landfill gas, digester gas, refinery gas, sour gas, blast furnace gas, coal-derived gas, producer gas, coke oven gas, or any gaseous fuel produced in a process which might result in highly variable sulfur content or heating value.

NR 440.50(2)(m) (m) “Offshore platform gas turbines” means any stationary gas turbine located on a platform in an ocean.

NR 440.50(2)(n) (n) “Peak load” means 100% of the manufacturer’s design capacity of the gas turbine at ISO standard day conditions.

NR 440.50(2)(p) (p) “Regenerative cycle gas turbine” means any stationary gas turbine that recovers heat from the gas turbine exhaust gases to preheat the inlet combustion air to the gas turbine.

NR 440.50(2)(q) (q) “Simple cycle gas turbine” means any stationary gas turbine which does not recover heat from the gas turbine exhaust gases to preheat the inlet combustion air to the gas turbine, or which does not recover heat from the gas turbine exhaust gases to heat water or generate steam.

NR 440.50(2)(r) (r) “Stationary gas turbine” means any simple cycle gas turbine, regenerative cycle gas turbine or any gas turbine portion of a combined cycle steam/electric generating system that is not self-propelled. It may, however, be mounted on a vehicle for portability.

NR 440.50(2)(s) (s) “Turbines employed in oil or gas production or oil or gas transportation” means any stationary gas turbine used to provide power to extract crude oil or natural gas, or both, from the earth or to move crude oil or natural gas, or both, or products refined from these substances through pipelines.

NR 440.50(2)(t) (t) “Unit operating day” means a 24-hour period between 12:00 midnight and the following midnight during which any fuel is combusted at any time in the unit. It is not necessary for fuel to be combusted continuously for the entire 24-hour period.

NR 440.50(2)(u) (u) “Unit operating hour” means a clock hour during which any fuel is combusted in the affected unit. If the unit combusts fuel for the entire clock hour, it is considered to be a full unit operating hour. If the unit combusts fuel for only part of the clock hour, it is considered to be a partial unit operating hour.

NR 440.50(3) (3) Standard for nitrogen oxides.

NR 440.50(3)(a) (a) On and after the date on which the performance test required by s. NR 440.08 is completed, every owner or operator subject to the provisions of this section, as specified in pars. (b), (c) and (d), shall comply with one of the following, except as provided in pars. (e) through (L).

NR 440.50(3)(a)1. 1. No owner or operator subject to the provisions of this section may cause to be discharged into the atmosphere from any stationary gas turbine, any gases which contain nitrogen oxides in excess of:

where:

STD is the allowable ISO corrected, if required as given in sub. (6) (c), NOx emissions (percent by volume at 15% oxygen and on a dry basis)

Y is the manufacturer’s rated heat rate at manufacturer’s rated load (kilojoules per watt hour), or actual measured heat rate based on lower heating value of fuel as measured at actual peak load for the facility (the value of Y may not exceed 14.4 kilojoules per watt hour)

F is the NOx emission allowance for fuel-bound nitrogen as defined in subd. 4.

NR 440.50(3)(a)2. 2. No owner or operator subject to the provisions of this section may cause to be discharged into the atmosphere from any stationary gas turbine, any gases which contain nitrogen oxides in excess of:

where:

STD is the allowable ISO corrected, if required as given in sub. (6) (c), NOx emissions (percent by volume at 15% oxygen and on a dry basis)

Y is the manufacturer’s rated heat rate at manufacturer’s rated peak load (kilojoules per watt hour), or actual measured heat rate based on lower heating value of fuel as measured at actual peak load for the facility (the value of Y may not exceed 14.4 kilojoules per watt hour)

F is the NOx emission allowance for fuel-bound nitrogen as defined in subd. 4.

NR 440.50(3)(a)3. 3. The use of F in subds. 1. and 2. is optional. That is, the owner or operator may choose to apply an NOx allowance for fuel-bound nitrogen and determine the appropriate F-value in accordance with subd. 4. or may accept an F-value of zero.

NR 440.50(3)(a)4. 4. If the owner or operator elects to apply an NOx emission allowance for fuel-bound nitrogen, F shall be defined according to the nitrogen content of the fuel during the most recent performance test required under s. NR 440.08 as follows:

- See PDF for table

where N is the nitrogen content of the fuel (percent by weight), or manufacturers may develop and submit to the department custom fuel-bound nitrogen allowances for each gas turbine model they manufacture. These fuel-bound nitrogen allowances shall be substantiated with data and must be approved for use by the administrator before the initial performance test required by s. NR 440.08.