LAKE COUNTY AIR QUALITY MANAGEMENT DISTRICT


Chapter II, Article III Geothermal Operations
 Adopted November 22, 1976


 

Section 421:

Sulfur Emissions

  1. A geothermal well operation may not emit total sulfur compounds expressed as hydrogen sulfide in excess of one hundred and fifty (150) ppm by weight unless: 
    1. The developer has installed an operable control system capable of achieving a seventy-five percent (75%) or greater reduction in hydrogen sulfide emission, or 
    2. The developer documents that it is engaged in an active program of research and development of technology for abating hydrogen sulfide emissions from geothermal well drilling acceptable to the Air Pollution Control Officer, and 
    3. The emissions from such operation do not cause the one hour ambient air standard for hydrogen sulfide to be exceeded. 
    The Air Pollution Control Officer may waive the requirements of this Section 421 provided that the developer installs and maintains an approved hydrogen sulfide ambient air monitoring system in the prevailing downwind direction and provided that the ambient air standard is not exceeded. In no case may the Air Pollution Control Officer waive the requirements of this Section if total sulfur compounds expressed as hydrogen sulfide exceed one thousand (1,000) ppm by weight. 
  2. No geothermal well operation shall emit total sulfur expressed as hydrogen sulfide in excess of twenty-four (24) pounds/day during the lowest bleed rate consistent with keeping the well potentially productive unless monitoring evidence is being and has been collected and convinces the Air Pollution Control Officer that the incremental sulfur emissions by wells of various developers are not likely to cause a violation or make a measurable contribution to an existing violation of the ambient air standard. 

Section 421.1: Geothermal Wells Particulate Emissions:

  1. All geothermal well operations shall abide by Rule 411 of the Rules and Regulations of the Air Quality Management District except that during the air drilling phase of the operation, the particulate emission rate may reach a level of one hundred (100) lbs/hr for a time period not to exceed sixteen (16) days. 
  2. In no case may the ambient particulate air standard be exceeded or caused to be exceeded during any phase of the geothermal well operation. 

Section 421.2: Geothermal Power Plant Operations:

  1. Power Plants 
    1. All geothermal power plants for which an Authority to Construct permit is initially issued before January 1, 1981 shall emit no more than one hundred and seventy-five (175) grams of hydrogen sulfide per gross megawatt hour. 
    2. All geothermal power plants for which an Authority to Construct permit is initially issued on or after January 1, 1981 shall emit no more than fifty (50) grams of hydrogen sulfide per gross megawatt hour. 
    3. All geothermal power plants shall, by January 1, 1990, emit no more than fifty (50) grams of hydrogen sulfide per gross megawatt hour. 
  2. Steam Transmission Lines 
    1. Effective January 1, 1980, the allowable rate of hydrogen sulfide emissions from steam transmission lines during a power plant outage shall be as defined in Table 2 below during scheduled outages and Table 3 below during unscheduled outages for all geothermal power plants and steam transmission lines operating in the Lake County Air Quality Management District. Time limitations are noted in minutes and begin when the generating unit is first off line, or venting of more than nine percent (9%) of normal, full, unabated steam flow of a unit occurs. Emission limitations to be reached by a noted time are given as the maximum allowable percent of full flow unabated hydrogen sulfide content of steam to the generating unit. In the event of an unscheduled outage, a decision as to the expected total time of the outage is to be made within ninety (90) minutes and entered into an appropriate log maintained at the site and readily accessible by the Lake County Air Quality Management District staff. For a scheduled outage, the expected down time shall be entered into this same log prior to initiating the outage. For the purposes of Section 421.2 B, two or more single generating unit power plants interconnected and capable on a continuous basis of shunting fifty percent (50%) of full steam flow of the larger of the units to other power plant(s) within thirty (30) minutes after initiation of an outage shall be considered a dual unit power plant. 
      This Regulation does not supersede or repeal any other rules or regulations of the Lake County Air Quality Management District and is intended to supplement other rules concerning the subject matter. 
    2. Effective January 1, 1985, hydrogen sulfide emissions shall be reduced to ten percent (10%) of unabated full steam flow within fifteen (15) minutes of initial outage. This applies to dual and single unit power plants whether a scheduled or unscheduled outage occurs. 
Section 422:

Geothermal Well Venting: No geothermal well operator shall intentionally exhaust into the atmosphere any well in excess of five (5) percent of full venting capacity without first notifying the Air Pollution Control Officer at least twenty-four (24) hours in advance of the proposed action, except:

  1. Operations during the exploratory phase under an Authority to Construct. 
  2. When abatement equipment proven effective is used in removing air contaminants for which there is an ambient air standard. 
  3. In cases where wells are being vented full open for purposes of testing the chemical and/or physical properties of the effluent. 
  4. In cases where the Air Pollution Control Officer requests chemical or physical tests to be performed on the well contents. 

 

TABLE 3A UNSCHEDULED POWER PLANT OUTAGES

Decision as entered in log < 420 minutes
Elapsed Time (Minutes)

15

30

60

90

90

420

Dual Units with one Unit Operative

90%

50%

35%

10%

10% continued

Back on Line or Hydrogen Sulfide Reduced to 10% of Full Unabated Hydrogen Sulfide Steam Flow Rate Until Startup Initiated

Single Units Capable of Shunting 35% of Full Steam Flow

90%

50%

35%

Enter into Log Expected Duration of Outage

35% Continued as at 60 Minutes Until Startup Initiated

Single Units without the Capability to Shunt 35% of Full Steam Flow

90%

50%

35%

Dual Units with both Units Down Simultaneously & Capable of Shunting Full Steam Flow

90%

50%

40%

Dual Units with Both Units Down Simultaneously & No Capability to Shunt Steam

90%

50%

40%

* The necessity for occasional venting in excess of limits specified under an upset in coordinating well throttling and power plant startup or shut down is acknowledged (refer to Article II, Section 510 LCAQMD Rules and Regulations)
 
 

TABLE 3B UNSCHEDULED POWER PLANT OUTAGES

No decision or decision as entered into log is greater than 420 minutes

Elapsed Time (Minutes)

150

300

Dual Units with one Unit Operative 10% continued as at 90 minutes until startup is initiated
Single Units Capable of Shunting 35% of Full Steam Flow 10% within 150 minutes and until startup is initiated
Single Units without the Capability to Shunt 35% of Full Steam Flow 10% within 150 minutes and until startup is initiated
Dual Units with both Units Down Simultaneously & Capable of Shunting Full Steam Flow Continue at 60 minutes unabated Hydrogen Sulfide steam flow rate 10% within 300 minutes and until startup is initiated
Dual Units with Both Units down Simultaneously & no Capability to Shunt Steam 10% within 150 minutes and until startup is initiated
* The necessity for occasional venting in excess of limited specified under an upset in coordinating well throttling and power plant startup or shutdown is acknowledged (refer to Article II, Section 510 of LCAQMD Rules and Regulations)