CALIFORNIA AIR RESOURCES BOARD



### APCD/AQMD RULE EVALUATION FORM -- Page 1 (Electronic Format)

I. GENERAL INFORMATION

District: Placer County Air Pollution Control District

Rule No(s): 233 Date adopted/Amended/Rescinded: December 10, 2009

Rule Title(s): Biomass Boilers

Date Submitted to ARB: December 30, 2009

If an Amended Rule, Date Last Amended (or Adopted): October 11, 2007

Is the Rule Intended to be Sent to the U.S. EPA as a SIP Revision? Yes No ( If No, do not complete remainder of form)

District Contact: John Finnell Phone Number: (530) 745-2324 E-mail Address: jfinnell@placer.ca.gov

Narrative Summary of New Rule or Rule Changes: New Rule Amended Rule

The October 11, 2007, rule amendment was forwarded to the California Air Resources Board (CARB) for approval into the California State Implementation Plan (SIP). This was approved by CARB and forwarded to the U.S. EPA for approval.

U.S. EPA declined to approve that amendment into the SIP as inconsistent with federal regulation and policy. The main objections were in two areas:

1. The 115 ppm limit for NOx does not apply during st artup and shutdown. Instead mass emission limits in the Permit to Operate would apply. Alt hough these limits were already in place in the both the District Permit to Operate and federal Title V, EPA has requested that the limitations be listed in the Rule itself.

2. The amendment must provide a dem onstration that both the length of time of the startups and shutdown and the emissions were minimized as much as technologically feasible.

The District requested the withdrawal of the amendment from SIP consi deration and has worked with both the sources involved and EPA to prepare an approvable amendment.

Section 101 has been amended to address those specific types of boilers by changing the applicability section to

read:

This rule applies to stoker and circulating fluidiz ed bed boilers and steam generators which have a heat input rating of less than 500 million Btu per hour and a potentia l to emit, as defined in Rule 502, NEW SOURCE REVIEW, 25 tons or more of NOx emissions and which hav e a primary energy source of biomass consisting of a minimum of 75 percent of the total annual heat input.

Any new stoker or circulating fluidized boilers rat ed less than 500 million Btu per hour would have to meet the proposed rule requirements and also apply Best Availabl e Control Technology (BACT) to be determined during the permitting process.

If other types of boilers were proposed for installation in Placer County, the equipment would fall under other existing boiler rules, or possibly a new regulation would be considered.

Section 200, Definitions, has been amended to add definitions of circulating fluidized bed boilers, stoker boilers and a curing startup.

Changes were also made to the startup and shutdown definit ions. A shutdown starts when fuel feed is curtailed and the unit begins cooling from the unit’s normal operating temperature, as specifi ed by the manufacturer, and ends when steam flow is zero or 24 hours has elapsed sinc e the start of the shutdown, whichever occurs first.CALIFORNIA AIR RESOURCES BOARD



### APCD/AQMD RULE EVALUATION FORM -- Page 2 (Electronic Format)

A boiler only has one purpose and that is to generate steam. The steam can be used for various reasons, including electric generation. When boiler conditions t hat do not allow for steam generation are reached, the boiler's operation is terminated. This point represents a useful indicator for the end of a "shutdown". Boiler steam flow is easily measured and is conti nuously monitored and recorded in the c ontrol room by the plant operator.

The steam flow was chosen instead of temperature because steam flow is more indicative of the operational condition of the boilers with regard to the end of a s hutdown versus a temperature measurement. In addition, because steam flow is likely to cease, within 2 to 5 hours, and before any lik ely temperature threshold that might

be used to indicate a shutdown condition such as 150 degrees Fahrenheit or a “cold” shutdown at ambient temperature, the period of time defined as a shutdown us ing a zero steam flow threshold versus a temperature threshold is shortened. For example, Ri o Bravo indicates that steam flow goes to zero at a boiler temperature of approximately 750 degrees F. At that time the biomass f uel is completely consumed and emissions are negligible. (See Attachment #4: Memo from Rio Bravo.) Therefore using zero steam flow to denote the end of a shutdown effectively reduces the possible period of time during wh ich alternative emission limits for shutdown may be used. In addition, the alternative emission limits proposed for shutdowns are only effective when the CO2 level is

reduced to below 10% due to the shut down conditions of reduced combustion.

Section 301, Limitations, which addresses limitations during normal operation, has been changed to add a carbon monoxide (CO) limitation for each type of boiler. These lim itations currently exist in the Permits to Operate for each facility.

To address EPA's concerns in effort to make the am endment SIP approvable, this rule amendment includes the mass emission limitations in pounds per hour in Section 302, Startup and Shutdown Provisions.

Pollutant(s) Regulated by the Rule (Check): ROG (NOx) SO2 (CO) PM TAC (name):

II. EFFECT ON EMISSIONS

Complete this section ONLY for rules that, when implemented, w ill result in quantifiable changes in emissions. Attach referenc e(s) for emission factor(s)

and other information. Attach calculation sheet showi ng how the emission information provided below was determined

.

Net Effect on Emissions: Increase Decrease N/A

Emission Reduction Commitment in SIP for this Source Category: NA

Inventory Year Used to Calcul ate Changes in Emissions: NA Area Affected: NA

Future Year Control Profile Estimate (Provide information on as many years as possible) : NACALIFORNIA AIR RESOURCES BOARD



### APCD/AQMD RULE EVALUATION FORM -- Page 3 (Electronic Format)

5/1/2002 3

Baseline Inventory in the SIP for the Control Measure: NA

Emissions Reduction Commitment in the SIP for the Control Measure: NA

Revised Baseline Inventory (if any): NA

Revised Emission Reduction Estimate (if developed): NA

Note that the district’s input to the Rule Evaluation Form will not be used as input to the ARB’s emission forecasting and planning.

III. SOURCES/ATTAINMENT STATUS

District is: Attainment Nonattainment Split

Approximate Total Number of Small (<100 T PY) Sources Affected by this Amendment: 0

Percent in Nonattainment Area: NA %

Number of Large (> 100 TPY) Sources Controlled: 2 Percent in Nonattainment Area: 100 %

Name(s) and Location(s) (city and county) of Large (> 100 TPY) Sources Controlled by Rule (Attach additional sheets as

necessary) : Rio Bravo, Lincoln and Sierra Pacific Industries, Lincoln.

IV. EMISSION REDUCTION TECHNOLOGY

Does the Rule Include Emission Limits that are Continuous? Yes No

If Yes, Those Limits are in Section(s) Section 301, Limitations and Section 302, St artup and Shutdown Provisions of the

Rule.

Other Methods in the Rule for Achi eving Emission Reductions are: NA

V. OTHER REQUIREMENTS

The Rule Contains:

Emission Limits in Section(s): Section 301, Limi tations and Section 302, Startup and Shutdown Provisions Work Practice Standards in Section(s): Se ction 401, Operation and Maintenance Plan Recordkeeping Requirements in Section(s): Section 501, Recordkeeping Reporting Requirements in Section(s): Section

502.3.CALIFORNIA AIR RESOURCES BOARD



### APCD/AQMD RULE EVALUATION FORM -- Page 4 (Electronic Format)

VI. IMPACT ON AIR QUALITY PLAN

No Impact Impacts RFP Impacts attainment

Discussion: The amendment adds CO limitat ions to the Limitations and also NOx and CO pounds per hour limitations to the Startup and Shutdown Provisions. These limitations are currenlty in existing permits to operate.