2) If each of the individual traverse point NOx concentrations, normalized to 15% O2, is within ± 5% of the mean normalized concentration for all traverse points, then you may sample at a single point, located at least one meter from the stack wall or at the stack centroid.

NR 440.50(6)(b)3. 3. Other acceptable alternative reference methods and procedures are given in par. (d).

NR 440.50(6)(c) (c) The owner or operator shall determine compliance with the applicable nitrogen oxides emission limitation in sub. (3) and shall meet the performance test requirements of s. NR 440.08 as follows:

NR 440.50(6)(c)1. 1. For each run of the performance test, the mean nitrogen oxides emission concentration (NOxo) corrected to 15% O2 shall be corrected to ISO standard conditions using the following equation. Notwithstanding this requirement, use of the ISO correction equation is optional for: lean premix stationary combustion turbines; units used in association with heat recovery steam generators (HRSG) equipped with duct burners; and units equipped with add-on emission control devices:

where:

NOx is the emission concentration of NOx at 15% O2 and ISO standard ambient conditions, ppm by volume, dry basis

NOxo is the mean observed NOx concentration, ppm by volume, dry basis, at 15% O2

Pr is the reference combustor inlet absolute pressure at 101.3 kilopascals ambient pressure, mm Hg

Po is the observed combustor inlet absolute pressure at test, mm Hg

Ho is the observed humidity of ambient air, g H2O/g air

e is the transcendental constant, 2.718

Ta is the ambient temperature, K

NR 440.50(6)(c)2. 2. The 3-run performance test required by s. NR 440.08 shall be performed within ± 5% at 30, 50, 75 and 90-to-100% of peak load or at 4 evenly-spaced load points in the normal operating range of the gas turbine, including the minimum point in the operating range and 90-to-100% of peak load, or at the highest achievable load point if 90-to-100% of peak load cannot be physically achieved in practice. If the turbine combusts both oil and gas as primary or backup fuels, separate performance testing is required for each fuel. Notwithstanding these requirements, performance testing is not required for any emergency fuel, as defined in sub. (2) (e).

NR 440.50(6)(c)3. 3. For a combined cycle turbine system with supplemental heat (duct burner), the owner or operator may elect to measure the turbine NOx emissions after the duct burner rather than directly after the turbine. If the owner or operator elects to use this alternative sampling location, the applicable NOx emission limit in sub. (3) for the combustion turbine shall still be met.

NR 440.50(6)(c)4. 4. If water or steam injection is used to control NOx with no additional post-combustion NOx control and the owner or operator chooses to monitor the steam or water to fuel ratio in accordance with sub. (5) (a), then that monitoring system shall be operated concurrently with each EPA Method 20, ASTM D6522-00, incorporated by reference in s. NR 440.17 (2) (a) 70., or Method 7E run and shall be used to determine the fuel consumption and the steam or water to fuel ratio necessary to comply with the applicable sub. (3) NOx emission limit.

NR 440.50(6)(c)5. 5. If the owner operator elects to claim an emission allowance for fuel bound nitrogen as described in sub. (3), then concurrently with each reference method run, a representative sample of the fuel used shall be collected and analyzed, following the applicable procedures described in subd. 9. These data shall be used to determine the maximum fuel nitrogen content for which the established water or steam to fuel ratio will be valid.

NR 440.50(6)(c)6. 6. If the owner or operator elects to install a CEMS, the performance evaluation of the CEMS may either be conducted separately, as described in subd. 7., or as part of the initial performance test of the affected unit.

NR 440.50(6)(c)7. 7. If the owner or operator elects to install and certify a NOx CEMS under sub. (5) (e), then the initial performance test required under s. NR 440.08 may be done in the following alternative manner:

NR 440.50(6)(c)7.a. a. Perform a minimum of 9 reference method runs, with a minimum time per run of 21 minutes, at a single load level, between 90 and 100% of peak, or the highest physically achievable, load.

NR 440.50(6)(c)7.b. b. Use the test data both to demonstrate compliance with the applicable NOx emission limit under sub. (3) and to provide the required reference method data for the RATA of the CEMS described under sub. (5) (b).

NR 440.50(6)(c)7.c. c. The requirement to test at 3 additional load levels is waived.

NR 440.50(6)(c)8. 8. If the owner or operator is required under sub. (5) (f) to monitor combustion parameters or parameters indicative of proper operation of NOx emission controls, the appropriate parameters shall be continuously monitored and recorded during each run of the initial performance test, to establish acceptable operating ranges, for purposes of the parameter monitoring plan for the affected unit, as specified in sub. (5) (g).

NR 440.50(6)(c)9. 9. To determine the fuel bound nitrogen content of fuel being fired if an emission allowance is claimed for fuel bound nitrogen, the owner or operator may use equipment and procedures meeting the requirements of the following:

NR 440.50(6)(c)9.a. a. For liquid fuels, ASTM D2597-94 (reapproved 1999), D4629-02, D5762-02 or D6366-99, incorporated by reference in s. NR 440.17 (2) (a) 33., 60., 66. and 70., respectively.

NR 440.50(6)(c)9.b. b. For gaseous fuels, analytical methods and procedures that are accurate to within 5% of the instrument range and are approved by the department.

NR 440.50(6)(c)10. 10. If the owner or operator is required under sub. (5) (i) 1. or 3 to periodically determine the sulfur content of the fuel combusted in the turbine, a minimum of 3 fuel samples shall be collected during the performance test. The samples shall be analyzed for the total sulfur content of the fuel using:

NR 440.50(6)(c)10.a. a. For liquid fuels, ASTM D129–00, D1266–98, D1552–01, D2622–98, D4294–02 or D5453–00, incorporated by reference in s. NR 440.17 (2) (a) 8., 18., 20., 34., 55. and 64., respectively.

NR 440.50(6)(c)10.b. b. For gaseous fuels, ASTM D1072–90 (Reapproved 1994), D3246–96, D4468–85 (Reapproved 2000) or D6667–01, incorporated by reference in s. NR 440.17 (2) (a) 15., 44., 59. and 72., respectively. The applicable ranges of some of the ASTM methods are not adequate to measure the levels of sulfur in some fuel gases. Dilution of samples before analysis, with verification of the dilution ratio, may be used, subject to the prior approval of the department.

NR 440.50(6)(c)11. 11. The fuel analyses required under subds. 9. and 10. may be performed by the owner or operator, a service contractor retained by the owner or operator, the fuel vendor, or any other qualified agency.