Mt. Poso Cogeneration Co. 

AAQIR/September 2009

1 

U.S. ENVIRONMENTAL PROTECTION AGENCY 

REGION IX 

STATEMENT OF BASIS AND 

AMBIENT AIR QUALITY IMPACT REPORT 

For a Clean Air Act 

Prevention of Significant Deterioration Permit 

Mt. Poso Cogeneration Company 

PSD Permit Number SJ 86-09 

January 2010 
Mt. Poso Cogeneration Co. 

AAQIR/September 2009

2 

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PROPOSED 

PREVENTION OF SIGNIFICANT DETERIORATION PERMIT 

Mt. Poso Cogeneration Company 

Statement of Basis and Ambient Air Quality Impact Report 

PSD Permit SJ 86-09 

Table of Contents 

Executive Summary ........................................................................................................................ 2 

1. Purpose of this Document ......................................................................................................... 3 

2. Applicant ................................................................................................................................... 3 

3. Project Location ........................................................................................................................ 3 

4. Project Description .................................................................................................................... 3 

5. Emissions from the Proposed Project ....................................................................................... 3 

6. Applicability of the Prevention of Significant Deterioration Regulations ................................ 5 

7. Best Available Control Technology .......................................................................................... 6 

8. Revised Emission Limits .......................................................................................................... 7 

9. Air Quality Impacts ................................................................................................................... 7 

10. Additional Impact Analysis ...................................................................................................... 7 

11. Endangered Species Act ........................................................................................................... 7 

12. Conclusion and Proposed Action .............................................................................................. 8 
Proposed Prevention of Significant Deterioration (PSD) Permit 

Statement of Basis and Ambient Air Quality Impact Report 

Mt. Poso Cogeneration Company

Executive Summary 

The Mt. Poso Cogeneration Company (MPCC) has applied for a modified Prevention of 

Significant Deterioration (PSD) permit under the federal Clean Air Act (CAA), 42 U.S.C. 

Section 7401 et seq. MPCC operates an existing 49.9 MW Atmospheric Circulating 

Fluidized Bed Combustor (boiler) Cogeneration Power Plant, located near Bakersfield, in 

Kern County California, which has been in operation since 1989. The initial PSD permit 

was issued for this facility by EPA Region 9 on January 8, 1987, and was previously 

modified on May 10, 1990, June 22, 1995, November 30, 1995, June 27, 1996 and July 8, 

1999. The facility currently utilizes a blend of coal, petroleum coke and tire derived fuel 

(TDF). The proposed modification is to allow MPCC to utilize a renewable fuel – woody 

biomass in addition to the existing fuels. Primary biomass fuel sources will include: 

agricultural waste in the form of orchard removals, orchard prunings, shells, and pits; and 

urban wood waste including tree trimmings, woody construction waste, pallets, and clean 

demolition wood from county and municipalities’ recycling programs. 

The proposed PSD permit is consistent with the requirements of the PSD program because the 

project will not result in a significant emissions increase of any attainment pollutant. Changes 

are being proposed to the existing PSD permit to allow the use of biomass as a new fuel and the 

construction of a new fuel handling system. 

 
1. Purpose of this Document 

This document serves as the Statement of Basis and Ambient Air Quality Impact Report 

for the proposed modified PSD permit for the Mt. Poso Cogeneration Company 

(Mt. Poso). This document describes the legal and factual basis for the proposed permit 

per 40 CFR 124.7, including requirements under the PSD regulations at 40 CFR 52.21. 

2. Applicant 

Mt. Poso Cogeneration Company (Mt. Poso) 

8302 Espresso Drive Suite 130 

Bakersfield, CA 93312 

3. Project Location 

The Mt. Poso power plant is located at 36157 Famoso Hwy, Bakersfield, California. The 

project is within the San Joaquin Valley Air Pollution Control District (SJVAPCD or 

District). 

4. Project Description

Mt. Poso operates an existing 49.9 MW Atmospheric Circulating Fluidized Bed 

Combustor Cogeneration Power Plant. Mt. Poso facility has been in operation since 

1989. The facility currently utilizes a blend of coal, petroleum coke and tire derived fuel 

(TDF). The proposed modification is to allow Mt. Poso to utilize a renewable fuel – 

woody biomass in addition to the existing fuels. Primary biomass fuel sources will 

include: agricultural waste in the form of orchard removals, orchard prunings, shells, and 

pits; and urban wood waste including tree trimmings, woody construction waste, pallets, 

and clean demolition wood from county and municipality recycling programs. 

In order to accommodate the new biomass fuel, Mt. Poso is proposing to add a new 

material handling and loading system and make minor physical modifications to the 

existing boiler unit. The new system consists of a receiving, conveying, screening, and 

stacking operation (SJV unit S-91-10) and a reclaiming operation (SJV unit S-91-11) to 

store the additional volume of fuel required. In addition to EPA’s PSD construction 

permit, SJVAPCD will issue an NSR construction permit for the following equipment: 

SJV Unit S-91-10: The proposed system will consist of four truck receiving areas 

equipped with enclosed hoppers and truck tippers and one walking floor capable 

of receiving 250 tons/hr of material (12 hours/day, 6 days/week). The biomass 

will be sent through a magnetic separator and will then be sorted through a disc 

screen and a hammer mill (hog). Fully enclosed Tubulators that float a rubber 

conveyor belt over a thin sheet of air will carry the material through fully 

enclosed transfer towers and stack the material in two piles (4 million ft3

 capacity 

per pile). 

SJV Unit S-91-11: The reclaiming portion of this operation consists of a 

reclaiming chain (both towers capable of pulling 60 tons/hr of material 24 
hours/day and 7 days/week) that will rake the material off the pile onto a 

conventional conveyor belt, through another magnetic pickup point, and into a 

gyrating screen to remove fines. From here the fines will be exported to a fully 

enclosed truck loadout using a screw-type conveyor. The biomass that passes the 

screen will then be transported to the fuel bin for combustion. The existing fuel 

receiving and transferring operation, permit S-91-1-9, will be cancelled upon 

implementation of these new ATCs. 

5. Emissions from the Proposed Project 

Evaluation of Trial Burn Emission Data

On January 9, 2009, EPA issued an Administrative Amendment (AA) to the PSD permit 

for this facility to allow a 6-month trial burn using biomass as an alternative fuel in order 

to collect relevant emissions data for the modified operation. On July 22, 2009, EPA 

extended the AA to allow continuation of the trial burn for an additional 6 month period. 

As required by the AA, Mt. Poso has submitted monthly reports containing data related to 

the trial burn. EPA has reviewed this data for the periods of February through June 2009. 

The data shows that while burning up to 32% biomass, the boiler was able to comply 

with the applicable emission limits though the use of existing control devices. These 

control devices include ammonia injection to control thermal NOx, limestone injection to 

control SO2, and cyclones and baghouses to control PM and PM10. Both the NOx and 

SOx control devices work on a feed back system, which increases the injection of 

ammonia or limestone as NOx or SOx emission levels rise and maintain NOx and SOx

emissions at specified emission rates. The control efficiency of the existing baghouses is 

not expected to change. In addition, the extended combustion zone residence time in a 

circulating fluidized bed combustor results in minimization of CO and hydrocarbons, 

independent of the fuel blend. 

Based on the emissions data and material profiles contained in the monthly reports, the 

source has requested to be allowed to burn up to 100% biomass by weight. EPA believes 

that with the continued use of the existing control equipment, the source will be able to 

continue to comply with their permitted emission limits at the proposed solid fuel loading 

rate of 58,333 lbs/hr and is therefore granting the request to modify the existing permit 

and allow a new fuel rate limit for biomass. EPA also notes that the boiler is equipped 

with a Continuous Emission Monitoring System (CEMS) unit to measure NOx, SOx, O2

and CO emissions and verify compliance. Records of fuel processed, source test results 

and emission factors will be used to determine compliance with PM and PM10 emission 

limits. The number of trucks delivering fuel to the facility will be limited to 120 per day 

to limit fugitive PM10 emissions from these trucks. 

The project proposes the use of urban wood waste which is generally defined as tree 

trimmings, woody construction waste, pallets, and clean demolition wood from county 

and municipality recycling programs. In order to ensure this waste does not contain other 

contaminants not evaluated under this action, the revised PSD permit will include a 

condition restricting the content of non-biomass materials (such as plastics, metal, 

painted and preservative-treated wood, roofing material, fiberglass, etc.) to no more than 
1% by weight of all biomass combusted. Delivery of each bio-mass load will be 

inspected for such materials, and the source will be required to sample a random biomass 

load upon EPA request to ensure compliance with this provision. 

Evaluation of Projected Emission Increases

The San Joaquin Valley Unified Air Pollution Control District (District) is currently 

classified attainment for NO2, PM10, SO2 and CO. The Mt. Poso facility is currently a 

PSD major source for NOx, SO2 and CO. Mt. Poso has recently revised its local NSR 

permit issued by the District to take federally enforceable limits for NOx, SOx and CO 

emissions and is proposing to take a federally enforceable PM10 emission limit in the 

PSD permit, as indicated in Table 5-B. Tables 5-A, 5-B and 5-C below summarize the 

pre-project baseline actual emissions, the post-project emissions based on potential to 

emit (PTE), and the emission increase/decrease for each pollutant, respectively. 

Table 5-A 

Pre-project Baseline Actual Emission Rates* 

Pollutant Tons/year 

Nitrogen Oxides (NOx) 192.0

Particulate Matter – 10 microns (PM10) 11.9 

Sulfur Oxides (SO2) 65.0 

Carbon Monoxide (CO) 86.1

*Baseline years are 2004 and 2005 for NOx, SO2 and CO 

 Baseline years for PM10 are 7/1/07 through 6/31/09 

Table 5-B

Maximum (PTE based) Post-project Emission Rates* 

Pollutant Tons/year 

Nitrogen Oxides (NOx) 231.5

Particulate Matter – 10 microns (PM10) 26.7 

Sulfur Oxides (SO2) 104.5 

Carbon Monoxide (CO) 185.7

*PTE based on enforceable emission limits in District or PSD permit 

Table 5-C

Emission Increases from Project 

Pollutant Tons/year 

Nitrogen Oxides (NOx) 39.5

Particulate Matter – 10 microns (PM10) 14.9 

Sulfur Oxides (SO2) 39.5 

Carbon Monoxide (CO) 99.6

6. Applicability of the Prevention of Significant 
Deterioration Regulations 

The PSD regulations (40 CFR 52.21) define a “major source” as any source type 

belonging to a list of 28 source categories which emits or has the potential to emit 100 

tons per year (tpy) or more of any attainment pollutant regulated under the Clean Air Act, 

or any other source type which emits or has the potential to emit such pollutants in 

amounts equal to or greater than 250 tpy. Since the combustion boiler is rated at 620 

MMbtu/hr, it is one of the listed 28 source categories specified in the PSD regulations, 

therefore the 100 tpy major source threshold applies to this facility. 

The District where this project is located, is classified as a federal non-attainment area for 

PM2.5 and ozone, therefore PM2.5 and VOC (an ozone precursor) emissions will be 

regulated by the New Source Review (NSR) permit issued by the District and are not 

addressed by this PSD evaluation. 

Mt. Poso is currently a PSD major source, therefore the change in emissions from the 

proposed project must be evaluated to determine if the project will result in a significant 

or significant net emissions increase of any attainment pollutant. Using the data provided 

in Tables 5-A through 5-C above, Table 6-A below summarizes the projected emission 

increases and significant thresholds for each attainment pollutant. The project will not 

result in a significant increase of any attainment pollutant subject to the PSD regulations. 

Accordingly, the proposed project does not trigger any major source PSD requirements. 

Table 6-A 

Significant Emission Threshold Evaluation (tons per year)

Pollutant Projected 

Increase

Significant 

Threshold

s

Significant 

Increase?

Nitrogen Oxides (NOx) 39.5 40 No

Particulate Matter – 10 microns (PM10) 14.9 15 No 

Sulfur Oxides (SO2) 39.5 40 No

Carbon Monoxide (CO) 99.6 100 No

EPA notes that all of the emission increases are close to the significant emission 

thresholds because Mt. Poso chose to limit their post-project PTE to avoid these 

thresholds through the use of federally enforceable permit conditions in either their 

District issued NSR permit or EPA issued PSD permit. 

7. Best Available Control Technology 

PSD regulations require that a Best Available Control Technology (BACT) determination 

be made for each pollutant subject to major PSD review. As noted in Section 6 above, 

this project does not trigger a major PSD review therefore the application of BACT is not 

required for this project. 
8. Revised Emission Limits 

The mass and concentration emission limits in the current PSD permit will remain in 

effect. A new annual emission limit has been added as Section IX.G. to ensure this 

project will not result in a significant increase in PM10 emissions. 

9. Air Quality Impacts 

As noted in Section 6 of this review, this project will not result in a major PSD 

modification; therefore an Air Quality Impact Analysis is not required. 

10. Additional Impact Analysis 

As noted in Section 6 of this review, this project will not result in a major PSD 

modification; therefore no additional Impact Analysis is required. 

11. Endangered Species Act 

Pursuant to Section 7 of the Endangered Species Act (ESA), 16 U.S.C. §1536, and its 

implementing regulations at 50 C.F.R. Part 402, EPA is required to ensure that any action 

authorized, funded, or carried out by EPA is not likely to jeopardize the continued 

existence of any endangered species or threatened species or result in the destruction or 

adverse modification of such species’ designated critical habitat. EPA determined that 

this PSD permitting action is subject to ESA Section 7 requirements. 

On August 31, 2009, EPA received a document titled “Biological Pre-Construction 

Survey for the Mount Poso Cogeneration Plant Expansion, Kern County, California” that 

served as the Biological Assessment (BA) prepared by the applicant’s consultant, Quad 

Knopf. 

On September 16, 2009, EPA provided the BA to FWS and requested concurrence that 

the project is not likely to adversely affect any endangered species know to be in the area, 

such as the San Joaquin kit fox, blunt-nosed leopard lizard (Gambelia sila), California 

jewelflower (Calanthus californicus), and San Joaquin wooly-threads (Lambertia 

congdonii). 

On December 21, 2009, FWS informed EPA that the projects fencing in of 20 acres 

would have a permanent impact upon potential San Joaquin kit fox foraging habitat. At 

this time FWS is working with Mt. Poso to ensure compliance with all ESA requirements 

prior to issuance of a PSD by EPA. EPA will proceed with issuance of its final PSD 

permit decision after making a determination that issuance of the permit will be 

consistent with ESA requirements. In making this determination, EPA will consider 

actions taken, or to be taken, by the applicant to ensure ESA compliance. 
12. Conclusion and Proposed Action 

Based on the information supplied by the applicant, and the evaluation provided above 

which determined this project will not result in a major PSD modification, EPA is 

proposing issuance of a modified PSD permit.