Addendum to DEQ BART Report for the Boardman Power Plant (November 11, 2010)

Page 1

INTRODUCTION:

PGE and several citizen groups asked DEQ to re-open the comment period on proposed pollution 

control rules for the Boardman coal-fired power plant to consider new information. PGE 

proposed a new approach to satisfying the Clean Air Act BART requirements that would require 

the Boardman Plant to meet increasingly stringent emission limits, close the plant no later than 

December 31, 2020, and eliminate existing rules that allow the plant to operate indefinitely. 

DEQ proposed rules that would address PGE’S request and re-opened the comment period from 

October 29 through November 15, 2010. Provided below is DEQ’s BART analysis for the new 

proposal.

CONTROL TECHNOLOGY INFORMATION

A discussion of the feasible control options is provided in the BART report prepared on 

September 1, 2010. The new proposal does not evaluate any new controls, but re-assesses the 

control effectiveness, cost effectiveness, and visibility improvement associated with the control 

options. Provided below is a summary of the feasible controls, the dates they would be 

employed, and the remaining useful life taking into consideration the plant closes on December 

31, 2010.

Feasible Controls:

Visibility Impairing 

Pollutant Control technology Date of operation

Remaining useful 

life (years)

NOx Low NOx burners with overfire air (LNB)7/1/11 9.5

Selective non-catalytic 

reduction (SNCR)

7/1/14 6.5

Selective catalytic reduction 

(SCR)

7/1/17 3.5

SO2 Reduced sulfur coal 

restriction (RSCR)

7/1/14 6.5

Dry sorbent injection (DSI) 7/1/14 6.5

Semi-dry flue gas 

desulfurization (SDFGD)

7/1/14 6.5

Wet flue gas desulfurization 

(WFGD)

7/1/14 6.5

PM Fabric filter (FF) 7/1/14 6.5

Provided below is a summary of the control effectiveness, emissions reductions, and visibility 

improvement for each of the control technologies.
Addendum to DEQ BART Report for the Boardman Power Plant (November 11, 2010)

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Control Effectiveness:

Visibility 

Impairing 

Pollutant

Control 

technology

Emission limit 

(lb/MMBtu)

Annual emission 

reduction

(tons/yr)a

Visibility 

improvement 

(dV)b

NOx LNB 0.23 4,756 1.44

SNCR w/LNB 0.19 5,729 1.62

SCR w/LNB 0.070 8,647 2.17

SO2 RSCR 0.60 331 0.43

RSCR/DSI 0.55 1,545 0.53

DSI -1 0.40 5,188 0.84

DSI -2 0.30 7,616 0.98

SDFGD 0.12 11,988 1.24

WFGD 0.070 13,202 1.19

PM FF 0.012 122 <0.1

a. The baseline for determining emissions reductions is the highest annual emission during 

2003 for each pollutant. NOx = 10,349 tons; SO2 = 14,902, PM = 417

b. Improvement is based on 22nd highest day impact in the Mt. Hood Wilderness area over 

the period of 2003 to 2005. Mt. Hood Wilderness is the highest impacted Class I area.

Provided below is a summary of the costs associated with each control technology considering 

the remaining useful life of the plant/technologies.

Cost effectiveness:

Visibility 

Impairing 

Pollutant

Control 

technology

Capital Cost 

(1000$)a

Total 

Annualized

Cost

(1,000$)a

Cost 

effectiveness 

($/ton)

Incremental 

cost 

effectiveness 

($/ton)

NOx LNB 31,585 5,358 1,102 ---

SNCR 

w/LNB

43,960 11,595 1,987 6,413

SCR w/LNB 223,651 74,189 8,475 21,452

SO2 RSCR 0 0 0 ---

RSCR/DSI 22,932 17,541 b ---

DSI -1 22,932 17,541 3,375 3,611

DSI -2 22,932 17,541 c c

SDFGD 352,915 78,259 6,523 8,929

WFGD 417,837 101,336 7,670 19,005

PM FF 100,442 22,842 186,102 ---

a. PGE estimate August 27, 2010 (2010 dollars)

b. This value is not calculated because RSCR/DSI is a fallback limit in case the DSI-1 limit 

cannot be met due to negative impacts on mercury and fine particulate matter controls.

c. These values are not calculated because DSI-2 is required in 2018, which is after the 

BART compliance period (e.g., 5 years after SIP approval).
Addendum to DEQ BART Report for the Boardman Power Plant (November 11, 2010)

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SELECTION OF BART:

If adopted as proposed, the BART/Regional Haze rules would require closure of the coal-fired 

power plant by December 31, 2010, consistent with PGE’s request. Taking into consideration 

the remaining useful life of the control technologies associated with plant closure, DEQ has 

determined that the following control technologies satisfy the BART requirements for the 

reasons provided.

Nitrogen Oxides (NOx):

Low NOx burners with over-fire air (LNB) technology is considered BART because the 

technology is cost effective and provides significant visibility improvement (>1 dV in Mt. Hood 

wilderness area). In addition, LNB can be installed as soon as 2011, providing 9.5 years of 

emission reductions.

Selective non-catalytic reduction (SNCR) was considered, but rejected because the technology 

provides only an additional 0.18 dV improvement in the Mt. Hood wilderness area (less 

improvement in all other wilderness areas) as compared to LNB. In addition, there is concern 

that excess ammonia emissions could produce fine particulate matter emissions that may have an 

adverse impact on the fine particulate (PM2.5) ambient air quality.

Selective Catalytic Reduction (SCR) is not required because under the current rules adopted in 

2009, the technology is not required to be installed until July 1, 2017, and the technology would 

not be cost effective for 3.5 years of operation.

Sulfur dioxide (SO2):

Reduced sulfur coal restriction (RSCR) is not considered BART because it would only provide 

0.43 dV visibility improvement in the Mt. Hood wilderness area. This level of improvement is 

not considered significant enough to satisfy the BART requirements.

Dry sorbent injection is considered to meet the BART requirements because it is cost effective 

and will provide significant visibility improvement (>0.5 dV) in at least the Mt. Hood wilderness 

area. Based on installations on smaller boilers, DSI can achieve emission reductions of 30 to 

70%. Considering the size of the Boardman unit (duct geometry and exhaust gas flow), a DSI 

system may perform in the lower range of the control effectiveness, but the effectiveness could 

be improved with additional operating experience. Therefore, DEQ proposes a limit of 0.40 

lb/MMBtu (35% emission reduction) in 2014 to satisfy the BART requirements. The limit is 

lowered to 0.30 lb/MMBtu (51% emission reduction) in 2018. The limit in 2018 could be met 

by further refinements to the DSI system or in combination with ultra-low sulfur coal or 

supplemental fuels, such as biomass.

PGE has raised concerns that DSI could negatively impact the mercury controls scheduled to be 

installed in 2011 as required by other DEQ rules. In addition, PGE is concerned that DSI will 
Addendum to DEQ BART Report for the Boardman Power Plant (November 11, 2010)

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generate fine particulate matter that would result in a requirement to install a fabric filter. The 

limits proposed by DEQ are intended to be met with the existing electrostatic precipitator (ESP) 

PM control equipment. The addition of a fabric filter would be cost prohibitive considering 

closure of the plant by December 31, 2020, as shown above. In order to address PGE’s 

concerns, the proposed rules include provisions for conducting pilot studies prior to the 

compliance dates in 2014 and 2018. The studies will evaluate commercially available sorbents, 

injection zones, and ESP collection efficiency. If it is determined that the DSI system would 

negatively impact the mercury controls or require a fabric filter, PGE may propose an alternative 

limit that will be established in the permit. The alternative limit must be the lowest achievable 

emissions limit without negatively impacting the mercury controls or requiring a fabric filter, but 

may not exceed 0.55 lb/MMBtu in order to achieve at least 0.5 dV improvement in the Mt. Hood 

wilderness area. For purposes of BART, 0.5 dV is considered significant and less than 0.5 is not 

considered significant.

Semi-dry flue gas desulfurization (SDFGD) and wet flue gas desulfurization (WFGD) are not 

considered to meet the BART requirements because they are not cost effective considering 

closure of the plant in 2020. The cost effectiveness of WFGD is $7,670/ton and the incremental 

cost of SDFGD is $8,929/ton, both considered too high for BART.

Particulate Matter:

The current electrostatic precipitator (ESP) is considered BART for particulate matter. A fabric 

filter is not cost effective and reductions in PM emission do not provide a noticeable 

improvement in visibility.

REGIONAL HAZE/BART SUMMARY:

BART control 

technology

Compliance 

Date

Emission 

Reduction (NOx

and SO2 tons/yr)

Mt. Hood 

Visibility 

Impacts

Visibility 

Improvement

Baseline ---- --- 4.98 ---

LNB 7/1/11 4,756 3.54 1.44

DSI-1 7/1/14 9,944 2.57 2.41

DSI-2 7/1/18 10,917 TBD* TBD

Plant Closure 12/31/20 12,373 0 4.98

*Running model, results should be available by 11/19.
Addendum to DEQ BART Report for the Boardman Power Plant (November 11, 2010)

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SUPPLEMENTAL INFORMATION:

Provided below is a table showing the visibility improvement in all Class I areas due to low NOx

burners with and without selective non-catalytic reduction. As shown, SNCR does not provide 

significant visibility improvement. The maximum improvement is 0.18 dV in the Mt. Hood 

wilderness area.

LNB/SNCR visibility improvement:

22nd high dV:

Class I area

22nd High dV

SNCR 

Improvement

LNB

(0.23 lb/MMBtu))

SNCR

(0.19 lb/MMtu))

Alpinae Lakes 1.564 1.484 0.080

Diamond Peak 0.757 0.730 0.027

Eagle Cap 1.611 1.528 0.083

Glacier Peak 1.008 0.959 0.049

Goat Rocks 1.702 1.611 0.091

Hells Canyon 1.435 1.367 0.068

Mt. Adams 1.899 1.772 0.127

Mt. Hood 3.537 3.356 0.181

Mt. Jeffereson 2.355 2.251 0.104

Mt. Ranier 1.478 1.416 0.062

Mt. Washington 1.711 1.635 0.076

Norch Cascades 0.747 0.710 0.037

Strawberry Mountain 1.281 1.204 0.077

Three Sisters 1.622 1.563 0.059

Columbia River Gorge 2.787 2.641 0.146

Maximum 3.537 3.356 0.181

msf.11/10/10