1 New York State Department of Environmental Conservation Best Available Retrofit Technology Determination

Facility Ravenswood Generating Station

Location Queens, NY Queens County
Permit ID 2-6304-00024

Source Category Fossil-fuel fired steam electric plant of more than 250 mmBtu/hr heat input

I. Introduction

The above referenced facility contains at least one emission source that falls under the requirements of the federal Best Available Retr ofit Technology (BART) rule under 40 CFR Part 51 and Appendix Y, and the New York State BA RT regulation as codified under 6 NYCRR Part 249. These requirements affect an emission s ource which fulfills the following criteria:

1. Falls within one of 26 sp ecific source categories,
2. Was not in operation prior to August 7, 1962 and was in existence on August 7, 1977, or underwent reconstruction between August 7, 1962 and August 7, 1977, and
3. Has a potential to emit (collectively, with ot her emission sources at the facility which fulfill items 1 and 2) of 250 tons per year or more of any visibility-impairing pollutant.

In accordance with BART requirements, each BART-eligible facility performed a BART analysis of controls for sulfur dioxide, nitrogen oxides and particul ate matter. This analysis took into account such factors as the cost of c ontrols, energy and non-air quality environmental impacts of compliance, any existing pollution co ntrol technology in use at the source, the remaining useful life of the source, and the de gree of improvement in visibility which may reasonably be anticipated to result from the use of such technology.

This document summarizes the reasoning be hind the Department’s BART determination, including the level of cont rols and emission limits that constitute BART for this facility’s eligible emission source(s). Each analysis and BART determination was submitted to the Federal Land Managers (FLMs) for their review in accordance with Regional Haze State Implementation Plan (SIP) requirements. Comments received from the FLMs on this determination will be included with its official submission to the U.S. Environmental Protection Agency (EPA).

The Department has modified this facility’s Title V permit to include the enforceable BART limits. The modifications were noticed in New York State’s Environmental Notice Bulletin on December 28, 2011. Upon completion of this pub lic notice period, the modified permit was submitted to EPA for review on February 14, 201 2. The final modified permit was issued on April 6, 2012. This permit is now being submitt ed to EPA as a revision to the New York Regional Haze SIP.2 II. BART Analysis Summary

TransCanada (TC) submitted a BART complian ce plan for the Ravenswood Generating Station dated September, 2010. Ongoing discussions betw een the Department and TC resulted in a BART determination for NO
x that differed from that of the initial plan; this alternative determination is described below.

The following emission sources had previously been identified as BART-eligible and were therefore included in the analysis:

Boiler No. 10 – Emission Unit U-00010; Emission Source ES10H/ES10R Boiler No. 20 – Emission Unit U-00020; Emission Source ES20H/ES20R Boiler No. 30 – Emission Unit U-00030; Emission Source ES30H/ES30R

• Each of these units is a Combustion Engin eering tangentially-fired boiler. Units 10, 20 and 30 have the ability to fire natural gas or No. 6 fuel oil. Natural gas is primarily used, with occasional use of residual fuel due to reliability requirements. These units have maximum heat input rates of 4,204 mmBtu /hr, 4,171 mmBtu/hr, and 9,379 mmBtu/hr, respectively. Units 10 and 20 commenced commercial operation in 1963 while Unit 30 began in 1965. All three units are equippe d with close coupled overfire air (CCOFA) systems and low NO
x burners (LNB) for NO
x control, while SO 2 emissions are limited by the use of low-sulfur fuel (0.3 percent by weight).

A summary of the analysis’ findings for each pollutant are as follows:

• SO 2

Due to the low-sulfur fuel oil standa rds contained in 6 NYCRR Part 225-1, the Ravenswood Generating Station has a permit condition which limits the maximum sulfur content of the fuel oil to 0.3 percent by weight for Units 10, 20 and 30. TC notes that this low-sulfur fuel is below the 1.0 percent sulf ur limit in oil referenced by the Appendix Y guidance. TC therefore requests that the curren t use of low-sulfur fuel oil be considered BART for SO 2

.

• NO
x

TC initially developed a NO
x compliance plan for BART based on a 100% oil-firing scenario. TC identified the combination of upgraded LNB with separated overfire air (SOFA) as cost-effective on a cost-per-ton basi s. (Other options were ruled out by TC based on overall or incremental cost effectiv eness.) Under this 100% oil-firing scenario, emissions were projected to drop from a ba seline of 0.24 lb/mmBtu to 0.17 lb/mmBtu, a 29% reduction. Modeling provided by TC demo nstrated that the maximum visibility improvement at a Class I area would be 0.12 deciviews at over $21.6M/deciview. TC cited the modest visibility improvements and high cost-per-deciview in ruling out LNB/SOFA for BART purposes, but committed to installing them solely to comply with the Department’s upcoming NO
x RACT requirements.3 In actuality, these units are predominantly na tural gas-fired. Recent data from the Clean Air Markets Division (CAMD) reveal that operations during 2009 and 2010 typically resulted in 30-day NO
x emission rates of around 0.07 lb/mmBtu. Emission rates were occasionally higher during the winter months due to the oil-firing requirements that are necessary to maintain electric system reliability in New York City. The emission reductions and visibility improvements ci ted in TC’s September, 2010 report are therefore overstated.

Whereas TC had committed to meeting NO
x RACT requirements through the installation of LNB/SOFA, they later changed their co mpliance approach to the “fuel switching” option granted by 6 NYCRR Part 227-2.5(a). This provision requires the source to burner a cleaner fuel during the oz one season; the annual average NO
x emission rate must still comply with the relevant limit contai ned in Part 227-2, which is 0.15 lb/mmBtu for these units. In addition to complying with NO
x RACT through the fuel switching option, TC has proposed to comply with BART by establishing a separate, more stringent NO
x limit of 0.15 lb/mmBtu on a 30-day rolling average.

• PM

TC identified three potential add-on BART c ontrol technologies for PM in addition to switching to low-sulfur distillate oil. A fabr ic filter (baghouse) was ruled out because of the technical issues with installation on o il-fired units. The remaining options are summarized below along with projected contro l efficiencies and cost effectiveness.4 PM Control Option Control Efficiency (%) Cost Effectiveness ($/ton)

Dry Electrostatic Precipitator (ESP) 99 $132,650

Wet ESP 99 $181,280
Switching to Distillate Fuel Oil 65 $174,970

Due to these excessive costs of controls, TC requests that curren t operations represent BART for PM on Units 10, 20 and 30.

III. BART Determination

The Department finds that the following sha ll constitute BART for the Ravenswood emission

sources:

• SO 2

These units are primarily natural ga s-fired, which yields negligible SO 2 emissions, but are required to burn oil at times due to reliabi lity concerns. The Department accepts the current No. 6 fuel sulfur limit of 0.3 percent by weight as BART for SO 2 . This is in line with the guidance provided by EPA for sulfur in fuel of 1.0 percent or less by weight (Appendix Y, Section IV.E.4, “SO 2 limits for Utility Boilers”). EPA also notes in the BART rule that “the most appropriate cont rol option for oil-fired EGUs, regardless of capacity, is to set limits on the sulfur content of the fuel oil burned in the unit” (70 FR 39133).

• NO
x

The Department accepts TC’s conclusion that additional controls are not necessary given the magnitude of visibility improvement and cost of controls on a per-deciview basis. The maximum visibility improvement at the Lye Brook Wilderness area was 0.12 deciviews at over $21.6M/deciview; the improve ment decreases into the hundredths of a deciview for other high ranked da ily visibility change days (8 th -highest values correspond to visibility improvements of 0.01 to 0.05 decivi ews). The Department also doesn’t feel that the addition of SNCR is necessary or appropriate, as minimal gains in NO
x reductions would result while li kely driving the co st-per-deciview valu es even higher.

The Department accepts the proposed NO
x BART limit of 0.15 lb/mmBtu, based on a 30- day rolling average. Although typical emi ssion rates are below this level – commonly around 0.07 lb/mmBtu – the required use of oil to maintain electric system reliability demands some leniency in the limit.5 • PM

The Department accepts that current operations represent BART for PM. TC adequately demonstrated that potential control options we re technically or econom ically infeasible. These units will retain the existing 0.1 lb/mmBtu particulate emission limit.