NORTHERN SONOMA COUNTY AIR POLLUTION CONTROL DISTRICT
RULE 455 - GEOTHERMAL EMISSION STANDARDS
(a) No person shall discharge into the atmosphere from any geothermal operation sulfur compounds, calculated as sulfur dioxide (SO2), in excess of 1,000ppm(v).
(aa) Nothwithstanding Rule 400(b) and Rule 455(a) geothermal wells on standby bleed shall be authorized in writing by the Control Officer to exceed 1000 ppm(v) (as measured in the bleeding steam) provided all the following conditions, which shall be annually verified, are met:
(b) No person shall discharge hydrogen sulfide (H2S) into the atmophere at a rate which exceeds those set forth in Table II and Table III.
Initially operated on or before March 31, 1979, (includes PG&E Geysers Units 1-12).
Initially operated after March 31, 1979, but initially issued an Authority to Construct or Determination of Compliance by March 31, 1980, (Includes PG&E Geysers Units 14, 15, & 17 and NCPA #2)
(NOTE *1 AND *3)
Initially issued an Authority to Construct or Determination of Compliance after March 31, 1989, (includes all others).
January 1, 1979
For Units 3,4, 5,6,11, & 12 emit no more than 10% of the H2S in the supplied steam at full power plant load or 200 g/hr/GMW ave. using allocation (See Notes *7).
January 1, 1980
10% of the H2S in the supplied steam at full
load operation for Units 3,4, & 11
July 15, 1981
200 g/hr/GMW for Units 5, 6, & 12 (Comply
as shown or per Note *8).
Units 1, 2, 3, 4, 5, 6, 7, 9, 10, 11, & 12:
June 1, 1985
each at 200 g/hr GMW (Comply as shown or per Note *8).
50 g/hr/GMW (Note * 8)
50/g/hr/GMW or 1 kg/hr (Note *10)
June 1, 1986
Units 1-12 each at 200 g/hr/GMW (Comply as shown
or per Note *8).
NOTES FOR TABLES II AND III
|NOTE 1||All geothermal emission sources, including new construction, must comply with all applicable future emission rate limits specified in these tables as they become effective.|
|NOTE 2||H2S emissions limitations for each category of emission source will become effective henceforth on the date indicated at the left of the Tables.|
|NOTE 3||The term "g/hr/GMW" shall read "grams/hr per Gross Megawatt". The rates of emission may be equaled but not exceeded. Gross Megawatt refers to the source's full load gross generating capacity of the turbine generator as guaranteed by the turbine generator manufacturer. Compliance shall be verified by the source testing or protocol method approved by the District for the applicable emission source(s). (See also note *8.)|
|NOTE 4||Individual well emissions shall be limited to 2.5 kg/hr/well unless a higher rate was determined by new source review or unless applicant provides data which subsequently can justify a re-determination of the emission rate by the Air Pollution Control Officer|
|NOTE 5||Small sources included continuous well and pipeline bleeds. Allowable emissions are those shown in Table III unless otherwise determined by the Air Pollution Control Officer.|
|NOTE 6||"Reduce H2S by 50%" shall mean emit no more than 50% of the H2S normally found in the supplied stream at full power load. "Dual Units" shall refer to those steam transmission lines associated with two power plant units located in the same building and therefore such associated steam transmission lines shall be considered as one source.|
|NOTE 7||Allocation method - If an emissions rate less than the required gm/hr/GMW is attained at one power plant unit, the excess reduction (in grams) can be credited to another power plant unit or apportioned to other power plant units. For instance, a 10 megawatt plant can be allowed to emit 2,000 gm H2S/hr, but if a credit of 500 gm H2S were allocated from another unit, it could emit 2,500 gm H2S/hr or 250 gm/hr/GMW. The allocation should be modified no more than quarterly and only if needed based on new data. (The major purpose of the allocation method is for individual power plant unit compliance verification and credit for greater H2S reduction than required.)|
Protocol Method - Each geothermal facility may be allowed to establish a protocol acceptable to the District which specifies the manner in which the facility will be operated to meet the emissions limitations set forth in Table II and Table III of this rule. Each protocol shall specify if applicable:
Each operating protocol can be modified by mutual
agreement between the District and the operator. Changes in operating protocol(s) shall not take effect until copies
of the revised protocol(s) are filed at the District office and the facility. Compliance with the operating protocol
approved by the Control Officer shall be deemed compliance with the H2S emissions limitations of this rule.
|NOTE 9||Stacking emission standards will be required of any steam transmission line or power plant which is expected to have on the average three (3) or more stacking events per year; the normal enforcement of equipment breakdown per rule 540 for the applicable stacking facility will be followed.|
The 1.0 kg H2S/hr limit shall apply only to geothermal power facilities with an electrical generation capacity of 20 Megawatts or less, provided:
Load Curtailment Emission Requirements - Each steam trans- mission line has a minimum steam flow rate, defined as "E", which results in the emission levels of Column "A" (Column D for Units 1 and 2 ). Each power plant unit, after curtailment, operates at a steam transmission line flow rate, defined as "F".