PLACER COUNTY 

AIR POLLUTION CONTROL DISTRICT 

STAFF REPORT 

AMENDMENT OF 

RULE 250, STATIONARY GAS TURBINES 

October 8, 2015 

Prepared by: 

John Finnell 

Manager of Permitting and Engineering 

 
STAFF REPORT  Amendment to Rule 250 Stationary Gas Turbines 

INTRODUCTION 

Rule 250, Stationary Gas Turbines, applies to all stationary gas turbines rated 0.3 megawatts 

(MW) and larger. 

This rule amendment was prompted by U.S. Environmental Protection Agency (U.S. EPA) 

notification that Rule 250 does not meet current Reasonably Available Control Technology 

(RACT). 

The most notable changes are: 

 The exemptions for pipeline and chemical processing gas turbines have been removed. 

 References to efficiency have been removed from the rule standards, as they are no 

longer required. 

 Limits during start-up and shutdown periods have been added for simple cycle gas 

turbines and for combined cycle gas turbines. 

PUBLIC COMMENTS 

A draft Rule 250 was prepared and public notice published on September 6, 2015 that the draft 

Rule 250 was available for review and comment beginning September 8, 2015. 

No public comments have been received. 

U.S. EPA provided verbal comments. The following changes were made in response to those 

comments: 

Section 102 – Deleted reference to Sections 110 and 111 which are now Sections 103 and 

104. They are in the rule but this language is not needed. 

Section 105 – Revised section which had included a new exemption from SU/SD for low use 

turbines. This section was changed to only allow an exemption from the monitoring provisions 

for existing low use units operating less than 877 hours per year. 

Section 204 – Major source definition was added. 

Section 206 – Deleted HHV definition as it is no longer needed. 

Section 206 – Performance testing definition was added. The District’s rules use the terms 

source testing and performance testing as interchangeable equivalent terms. 

Section 207 – Deleted LHV definition as it is no longer needed. 

Section 210 – Reinstated SCR definition that was previously in the rule. 

Section 301 – Added that the one-hour average is based on four consecutive 15-minute 

averages. Removed wording “thermal stabilization” and changed to “startup and shutdown”. 
STAFF REPORT  Amendment to Rule 250 Stationary Gas Turbines 

Section 501.1.3 – Deleted the 4,000 hr. requirement for CEMS, as other districts do not have 

this. However, an exemption is proposed, as shown in Section 105. 

Section 501.2 – No change to this section. The District uses the term performance testing 

interchangeably with source testing. A Performance Testing definition has been added in 

Section 206. 

Section 502.1 – Deleted sentence defining major source and added a major source 

definition. The District would like to keep the requirement that records be kept for major 

sources for 5 years and non-major sources for 2 years. 

BACKGROUND

There are currently two permitted facilities within the District that are subject to Rule 250. They 

are both owned and operated by the City of Roseville, Roseville Electric. One facility has two 

combined cycle gas turbine units with heat recovery and the other one has two simple cycle 

units. 

The District does not expect the proposed rule amendments to have a significant impact on either 

of these sources or the environment. It will not create emission reductions. This amendment 

simply provides an updated RACT rule. 

The amended rule, if approved, will also apply to any new sources. New sources will trigger 

Best Available Control Technology (BACT) requirements for NOx emissions. These will be 

more stringent than the requirements of this rule. 

Stationary gas turbines are engines consuming liquid or gaseous fuels, which produce 

mechanical power that can be used to perform mechanical work or can be converted into 

electrical power. After air is compressed in the compressor section of the engine, fuel is 

introduced and mixed with the air, and then the mixture is ignited in the combustor. The 

expanding combustion gases exhaust through the turbine section of the engine, causing the 

turbine blades to spin and thus creating shaft power. The combustion of fuel by the stationary 

gas turbine results in the emission of criteria pollutants: carbon monoxide (CO), oxides of 

nitrogen (NOx), oxides of sulfur (SOx), volatile organic compounds (VOC), and particulate 

matter ten microns (PM10). Many stationary gas turbines utilize selective catalytic reduction 

(SCR) as an emissions control technology. This control technology results in the emission of 

ammonia, which can negatively affect the respiratory system with acute and chronic exposures. 

In the simple cycle gas turbine, power plant electrical power is created from the generator driven 

by the gas turbine. 

A later development in stationary power generation is the combined cycle power plant, which 

utilizes additional components. The more complex combined cycle extracts useful heat energy 

from the gas turbine exhaust with a heat recovery steam generator. The heat recovery steam 

generator then channels the steam to drive a steam turbine. The shaft power from the steam 

turbine is used to drive an additional electric generator. The additional equipment of the 
STAFF REPORT  Amendment to Rule 250 Stationary Gas Turbines 

combined cycle power plant results in a greater amount of time necessary to reach steady-state 

operation compared to the simple cycle process. 

AMENDMENTS OF RULE 250 

Staff is proposing to make a number of amendments to update the rule and to gain EPA SIP 

approval. These amendments are described below. A strikeout version of the amended rule is 

included in this staff report. 

Section 100 General 

Section 101, Purpose, was revised to remove the reference to Best Available Retrofit 

Control Technology (BARCT) determinations. This is not needed. The rule amendment 

is intended to meet Reasonably Available Control Technology (RACT) requirements. 

Section 102, Applicability, was revised to remove references to Section 110 and 111. 

Section 110 is now 103. Section 111 is now 104. The exemptions for pipeline and 

chemical processing gas turbines were removed. There are none in Placer. If one was 

added, they should meet this rule, and the units would be subject to the more stringent 

Best Available Control Technology (BACT) standards when applying for a permit. 

Section 105, Exemption – Low Use Unit, was added to provide an exemption from the 

monitoring requirements in Section 501.1.3. Without the exemption, the low use units 

would need to add an expensive continuous monitoring system. 

Section 200 Definitions 

The definition of BARCT, chemical processing gas turbine, high heating value (hhv), low 

heating value (lhv), measured NOx emissions concentration, pipeline gas turbines and 

thermal stabilization were removed because the terms are not used in the proposed rule. 

The definition of performance testing was added to clarify that this meant stack emissions 

testing or source testing. 

A startup and a shutdown definition were added. The previous rule allowed a two hour 

startup period. The time allowed for startup for a combined cycle turbine was increased 

from two (2) hours to six (6) hours. 

 
STAFF REPORT  Amendment to Rule 250 Stationary Gas Turbines 

Section 300 Standards 

 

 Section 301, Limitations, currently has the standards shown below: 

 

EXISTING LIMITATIONS 

Unit Size 

Compliance limit 

NOx, ppm @ 15% O2

Megawatt Rating (MW) GasA OilB

0.3 to Less Than 2.9 MW 

and Units Greater Than or Equal to 4 MW That 

Operate Less Than 877 Hour/Year 

42 65 

2.9 to Less Than 10 MW 25 x EFF/25 65 

10.0 MW and Over with SCR 9 x EFF/25 25 x EFF/25 

10.0 MW and Over Without SCR 15 x EFF/25 42 x EFF/25 

A. GAS INCLUDES NATURAL, DIGESTER, AND LANDFILL GASES. 

B.OIL INCLUDES KEROSINE, JET, AND DISTILLATE. THE SULFUR CONTENT OF THE OIL SHALL BE LESS THAN 0.05%. 

 Where: EFF(efficiency) is the higher of the following: 

 301.1 EFF = 3412 x 100% 

 AHR 

[where: AHR = Actual Heat Rate at HHV of Fuel (BTU/KW-HR)], which is the 

demonstrated percent efficiency of the gas turbine only as calculated without 

consideration of any downstream energy recovery from the actual heat rate, 

(BTU/KW-HR) or 1.34 (BTU/HP-HR); corrected to the HHV (higher heating 

value) of the fuel and ISO conditions, as measured at peak load for that facility, or 

 301.2 EFF = MRE x LHV 

 HHV 

[where: MRE = Manufacturer's Rated Efficiency with Air Pollution Equipment at 

LHV.], which is the manufacturer's continuous rated percent efficiency of the gas 

turbine with air pollution equipment after correction from LHV to HHV of the 

fuel at peak load for that facility. 

 
STAFF REPORT  Amendment to Rule 250 Stationary Gas Turbines 

 PROPOSED CHANGES TO NOx EMISSION CONCENTRATION LIMITS

 

PROPOSED LIMITATIONS 

Unit Size 

Compliance limit 

NOx, ppm @ 15% O2

Megawatt Rating (MW) GasA OilB 

Units rated 0.3 to Less Than 2.9 MW 

OR 

Units Greater Than or Equal to 4 MW That 

Operate Less Than 877 Hour/Year 

42 65 

2.9 to Less Than 10 MW 25 65 

10.0 MW and Over 9 25 

A. GAS INCLUDES ONLY COMMERCIAL NATURAL AND LIQUIFIED PETROLEUM GASES.

B. OIL INCLUDES KEROSINE, JET, AND DISTILLATE OIL. THE SULFUR CONTENT OF THE OIL SHALL BE LESS THAN 0.05%. 

The proposed rule amendment removes the efficiency factor of EFF/25 which was 

applicable to the 9 and 25 ppm limits. These are no longer used or needed. This makes 

the rule standards more stringent without having to make additional calculations to 

determine compliance. 

The definition of EFF (Efficiency) was deleted because it is no longer used or needed. 

Section 302 Startup/Shutdown Combined Cycle 

This section adds emission limits during startup or shutdown periods. 

There is a concern that an exemption of emission limits during startup without other 

limitations would provide a loophole for operators to have significant emissions during 

startup. While there has been considerable discussion about startup and shutdown 

emissions, there is very little literature on actual emissions during these periods. The 

actual emissions vary depending on many factors including how long the turbine has 

been offline and ambient air temperature. 

The best way to limit emissions is to limit the length of time of a startup. The rule 

amendment allows up to six (6) hours which is sufficient time for a large combined cycle 

unit to come online, even if there is a problem initially on the startup. 

In addition, a startup/shutdown emission limit of 70 ppmv @15% O2 was added based on 

the most recent rule change found in Yolo-Solano Air Quality Management District 

(YSAQMD) Amendment to Rule 2.34 Stationary Gas Turbines. 

Alternatively, operators may comply by meeting a pounds per million British Thermal 

Unit limit (lbs./MMBtu) 

The startup/shutdown pounds per MMBtu/hr limit was based on the permit limit in the 

Roseville Electric Roseville Energy Park. The lbs/MMBtu of .016 was determined by 

dividing the NOx pounds per hour limit during startup by the input fuel rate in 

MMBtu/hr. 
STAFF REPORT  Amendment to Rule 250 Stationary Gas Turbines 

The emission limit of 226 @15% O2 when a turbine is operated on fuel oil was also 

found in the YSAQMD Amendment to Rule 2.34 Stationary Gas Turbines. 

Section 303 Startup/Shutdown Simple Cycle Units 

This section was added to require basic good practices be applied during startup or 

shutdown of simple cycle units. 

 Section 400 Administrative Requirements 

The compliance schedule in Section 401 and requirement to have an emission control 

plan in Section 402 were removed as they are no longer needed. 

 

 Section 500 Monitoring and Recordkeeping 

 

 Section 501 Monitoring 

The language requiring a NOx continuous emissions monitor on units 10 MW or greater 

that operated more the 4000 hours per year over the last three years prior to July 13, 1994 

has been changed to delete the wording, “that operated more than 4000 hours per year 

over the last three years prior to July 13, 1994”. 

A NOx monitor is now required unless a gas turbine is a low use unit and exempt under 

Section 105. 

Section 502 Recordkeeping 

A requirement was added for the owner or operator of a major source to maintain records 

for a period of five years. Non-major sources must keep records for a minimum of two 

(2) years. 

The reference to the demonstrated percent efficiency (EFF) was deleted as it is no longer 

used in the emission standards. 

The reference to recording in Pacific Standard Time was deleted at the request of 

Roseville Electric. 

Section 502.6 required maintaining a gas turbine operating log. This section was nearly 

identical to the previous section 502.5 and is deleted because it is redundant. 

Section 503 Test Methods 

The test methods for LHV and HHV of fuel were deleted as they are not used in the 

proposed version of this rule. 
STAFF REPORT  Amendment to Rule 250 Stationary Gas Turbines 

COMPARISON TO OTHER APPLICABLE REGULATIONS AND REQUIREMENTS

New Source Performance Standards 

 

Stationary gas turbines with a 10 Million Btu per hour heat input rate at peak load (based on the 

higher heating value of the fuel fired) are subject to the requirements of the EPA’s New Source 

Performance Standards (NSPS) contained in 40 CFR Part 60, Subpart KKKK. Table 2 below 

presents a comparative analysis between specific elements of the proposed revised rule and the 

corresponding elements of the existing federal regulation. 

Comparison of Proposed Rule Revision Emission Limits with NSPS 40 CFR, Part 60, 

Subpart KKKK 

Turbine Rating District Rule 250 NOx Emission 

Limits, ppmv@15% O2

Federal Regulation 40 CFR Part 60, 

Subpart KKKK NOx Emission 

Limits, ppmv@15% O2

˂ 10 MW fired 

on Natural Gas 25 or 42 42, 100, or 150 

˂ 10 MW fired 

on fuel other 

than Natural Gas 

25, 42, or 65 96 or 150 

≥ 10 MW fired 

on Natural Gas 9 or 42* 15, 25, 42, 100, or 150 

≥ 10 MW fired 

on fuel other 

than Natural Gas 

9, 25, 42, or 65* 42, 74, 96, 100, or 150 

* The 42 and 65 ppmv NOx limits in these categories only apply to turbines which are limited to 

operating for less than 877 hours/year 

The standards for sulfur dioxide of 40 CFR Part 60, Subpart KKKK requires either that the 

emission of sulfur dioxide (SO2) from any stationary gas turbine not exceed 0.90 pounds per 

megawatt-hour or that the fuel burned not contain potential sulfur emissions in excess of 0.060 

pounds of SO2 per million BTU. The subpart also contains alternative compliance limits for 

turbines in a non-continental area or if the EPA administrator finds both that the turbine is 

located in an area where natural gas is not available, and that the removal of sulfur compounds 

would cause more environmental harm than benefit. District Rule 250 currently does not contain 

any restrictions on sulfur oxides and the proposed amendments will not add any restrictions. 

Emissions of sulfur oxides from stationary gas turbines will be limited by other District rules and 

regulations, as well as state-level regulations on fuel sulfur content. 

Stationary gas turbines with a 10 Million Btu per hour heat input rate at peak load (based on the 

lower heating value of the fuel fired) and not regulated under Subpart KKKK are subject to the 

requirements of NSPS contained in 40 CFR Part 60, Subpart GG. Table 3 below presents a 

comparative analysis between specific elements of the proposed revised rule and the 

corresponding elements of the existing federal regulation. 
STAFF REPORT  Amendment to Rule 250 Stationary Gas Turbines 

Comparison of Proposed Rule Revision Emission Limits with NSPS 40 CFR, Part 60, 

Subpart GG 

 

Turbine Rating 

District Rule 250 NOx 

Emission Limits, 

ppmv@15% O2

Federal Regulation 40 CFR Part 60, 

Subpart GG NOx Minimum Emission 

Limits, ppmv@15% O2

0.3 to Less Than 2.9 

MW 

And Units Greater 

Than or Equal to 4 

MW That Operate 

Less Than 877 

Hour/Year 

42 or 65 75 or 150 

2.9 to Less Than 10.0 

MW 25 or 65 150 

10.0 MW and Over 9 or 25 75 or 150 

The NOx emission limits presented for Subpart GG reflect the most stringent emission limits 

which can be increased to higher levels with an adjustment factor calculated from the 

manufacturer’s rated heat rate at the manufacturer’s rated peak load and a NOx emission 

allowance for fuel-bound nitrogen. 

 

The federal regulation requires that if a nonzero emission allowance for fuel-bound nitrogen is 

used in the calculation of the applicable NOx emission limit in Subpart GG, the owner or 

operator of the turbine shall monitor the nitrogen content of the fuel combusted by the approved 

methods. 

The standards for sulfur dioxide of 40 CFR Part 60, Subpart GG require that the emission of 

sulfur dioxide from any stationary gas turbine not exceed 0.015 percent by volume at 15 percent 

excess oxygen on a dry basis. The regulation also requires the fuel fired in a stationary gas 

turbine shall not contain sulfur in excess of 0.8 percent by weight. District Rule 250 currently 

does not contain any restrictions on sulfur oxides, and the proposed amendments will not add any 

restrictions. Emissions of sulfur oxides from stationary gas turbines will be limited by other 

District rules and regulations as well as state-level regulations on fuel sulfur content. 

Both 40 CFR Part 60, Subpart GG and District Rule 250 require monitoring of the emission unit 

to demonstrate compliance with the applicable emissions standards. The federal regulation 

requires monitoring of the total sulfur content of the fuel combusted in the turbine. This 

monitoring becomes elective if the owner or operator can demonstrate by approved means that 

the fuel being fired in the turbine meets the definition of natural gas given in the regulation. 

District Rule 250 has not contained, and the rule revision will not add, any limitations on sulfur 

dioxide emissions. 
STAFF REPORT  Amendment to Rule 250 Stationary Gas Turbines 

Reasonably Available Control Technology 

The revisions to this rule would establish for steady-state operation the same NOx emission 

limits as those currently established for stationary gas turbines by the Sacramento Metropolitan 

Air Quality Management District, Yolo-Solano AQMD and other districts, which are equal to or 

lower than the applicable standards established by the federal government under 40 CFR 60 

Subpart KKKK, and well below the lowest applicable standards required by Subpart GG. 

Best Available Retrofit Control Technology 

The Sacramento Federal Non-Attainment Area is classified by the EPA to be in severe 

nonattainment of the 8-hour national ambient air quality standard for ozone. According to 

Section 40920 of the California Health and Safety Code, a district with severe air pollution shall, 

to the extent necessary to meet the requirement that a district design a plan to achieve and 

maintain air quality standards by the earliest practicable date, include in the district plan all 

measures required for moderate and serious nonattainment areas. One of the measures for 

districts with serious air pollution is the use of the Best Available Retrofit Control Technology 

(BARCT) for existing permitted stationary sources. The only existing stationary gas turbines 

subject to the rule are operated by Roseville Electric. The District has not relied on the 

application of BARCT for stationary gas turbines as a means to achieve ambient air quality 

standards in the 2012 Triennial Assessment and Plan Update. BARCT is not required, and this 

rule does not establish BARCT. 

ANALYSIS 

The following Analysis and the subsequent Findings are intended to address the 

requirements set forth in the Health and Safety Code relating to adoption of a new or 

amended District Rule, as well as other State statutes referenced herein. 

1. Cost-Effectiveness of a Control Measure 

California Health & Safety Code (H&S) Section 40703 requires a District to 

consider and make public “the cost-effectiveness of a control measure”. Emission 

reductions are not anticipated. There will be no known costs to comply. 

2. Socioeconomic Impact 

H&S Section 40728, in relevant part, requires the Board to consider the 

socioeconomic impact of any new or amended rule if air quality or emission limits 

are significantly affected. The two facilities where the rule is applicable are in 

compliance with the proposed rule amendments. A socioeconomic impact is not 

anticipated. 

 
STAFF REPORT  Amendment to Rule 250 Stationary Gas Turbines 

3. Environmental Review and Compliance 

California Public Resources Code Section 21159 requires an environmental 

analysis of the reasonably foreseeable methods of compliance should be 

conducted. Compliance of the proposed rule amendment is expected to already 

be achieved. Staff has concluded that no adverse environmental impacts will be 

caused by compliance with the proposed rule amendment. 

According to the above conclusion, Staff finds that the proposed rule amendment 

is exempt from the California Environmental Quality Act (CEQA) because: (1) it 

can be seen with certainty that there is no possibility that the activity in question 

may have a significant adverse effect on the environment (CEQA Guidelines 

§15061(b) (3)), and (2) it is as an action by a regulatory agency for protection of 

the environment (Class 8 Categorical Exemption, CEQA Guidelines §15308). 

FINDINGS 

A. Necessity: The adoption of proposed amended Rule 250 satisfies the objective of 

the District to adopt RACT requirements. 

B. Authority: California Health and Safety Code, Sections 40000, 40001, 40701, 

40702, 40716, 41010, and 41013, are provisions of law that provide the District 

with the authority to adopt this proposed amended Rule. 

C. Clarity: There is no indication, at this time, that the proposed amended Rule is 

written in such a manner that persons affected by the Rule cannot easily 

understand them. 

D. Consistency: The proposed amended Rule is in harmony with, and not in conflict 

with or contradictory to, existing statutes, court decisions, or state or federal 

regulations. 

E. Non-duplication: The proposed amended Rule does not impose the same 

requirements as an existing state or federal regulation. 

F. Reference: All statutes, court decisions, and other provisions of law used by the 

District in interpreting this proposed amended Rule are incorporated into this 

analysis and this finding by reference. 

SUMMARY 

District Staff recommend the District Board conduct a public hearing and approve the 

amendments to Rule 250, Stationary Gas Turbines. 
STAFF REPORT  Amendment to Rule 250 Stationary Gas Turbines 

RULE 250, STATIONARY GAS TURBINES